Jonathan Jarecki

Arturo Herrera's hypothesis proposes that hydrated melanin in the skin absorbs light to break water molecules into oxygen and hydrogen, producing four free electrons that enter the mitochondrial electron transport chain to produce ATP.

"there was a—there's a researcher named Arturo Herrera out of Mexico, and he has a lab called the Human Photosynthesis Lab, where he studies this idea of quite literally human photosynthesis... essentially, you know, we all have melanin in our skin, and melanin is a semiconductor. So, it absorbs light, and then it can use that light to basically break bonds of molecules. And all the melanin in our body is hydrated... when melanin absorbs light, it can break the water bond, so the H2O. It breaks the H2O into oxygen and hydrogen, leaving four free electrons left over, which those electrons can go down the electron transport chain in your mitochondria, and then ultimately produce ATP." (said at 0:05:57)

The speaker accurately summarizes the hypothesis proposed by Mexican researcher Arturo Solís Herrera (director of the Human Photosynthesis Research Center). Solís Herrera has published narrative hypothesis papers claiming that hydrated melanin absorbs light energy to split water into hydrogen, oxygen, and high-energy electrons (analogous to chlorophyll in plant photosynthesis) to generate cellular energy. However, this concept is purely a fringe hypothesis by that author, lacking rigorous empirical validation or acceptance in mainstream biochemistry and cellular bioenergetics.

• supports: Unsuspected Intrinsic Property of Melanin to Dissociate Water Can Be Used for the Treatmen… (CNS & neurological disorders drug targets 2016) · cited 4x in the literature

  "The unexpected intrinsic property of melanin to absorb light energy and transform it into chemically based free energy can explain normal adhesion of the sensory retina to the pigment epithelium." (abstract, conclusions, passage verified)

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• supports: Cerebrospinal Fluid, Brain Electrolytes Balance, and the Unsuspected Intrinsic Property of… (CNS & neurological disorders drug targets 2018) · cited 11x in the literature

  "The discovery of the unsuspected intrinsic ability of melanin to dissociate and reform water molecules, similar to the role of chlorophyll in plants, was confirmed in the study of ISF and CSF biology." (abstract, conclusions, passage verified)

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Mature human red blood cells do not contain mitochondria, unlike other human cell types.

"besides red blood cells cuz they don't have mitochondria, but every single other one of your cells have thousands of mitochondria inside of one single cell." (said at 0:08:43)

Mature human red blood cells (erythrocytes) do not contain mitochondria. During the final stages of human erythropoiesis and reticulocyte maturation, developing red blood cells undergo programmed organelle clearance (mitophagy) and enucleation, producing mature erythrocytes that are entirely devoid of mitochondria and rely exclusively on anaerobic glycolysis for energy.

• supports: Mitochondrial clearance by autophagy in developing erythrocytes: clearly important, but ju… (Cell cycle (Georgetown, Tex.) 2010) · cited 62x in the literature

  "Erythrocytes are anucleated cells devoid of organelles. Expulsion of the nucleus from erythroblasts leads to the formation of reticulocytes, which still contain organelles. The mechanisms responsible for the final removal of organelles from developing erythroid cells are still being elucidated. Mitochondria are the most abundant organelles to be cleared for the completion of erythropoiesis." (abstract, passage verified)

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• supports: Mitochondrial regulation of erythropoiesis in homeostasis and disease. (British journal of haematology 2024) · cited 17x in the literature

  "The end stages of the erythroid cell maturation process primarily include chromatin condensation and nuclear polarization, followed by nuclear expulsion called enucleation and clearance of mitochondria and other organelles to finally generate mature RBCs. While healthy RBCs are devoid of mitochondria, recent evidence suggests that mitochondria are actively implicated in the processes of erythroid cell maturation" (abstract, passage verified)

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Cytochrome c oxidase absorbs red and infrared light, which triggers the release of nitric oxide and helps pump protons across the mitochondrial gradient to increase ATP production.

"One of the protein complexes is called cytochrome c oxidase. Cytochrome c oxidase is basically this chromophore. Chromophore is just something that absorbs light. Cytochrome c oxidase absorbs red and infrared light, releasing nitric oxide, allowing electrons and protons to funnel through, push protons against the gradient, have a higher charge on the mitochondria, producing more ATP." (said at 0:10:37)

The speaker accurately describes the leading mechanistic model of photobiomodulation (PBM). Cytochrome c oxidase (complex IV of the mitochondrial electron transport chain) contains heme and copper chromophores that absorb red and near-infrared light (approx. 600–1000 nm). Photon absorption leads to the photodissociation/release of inhibitory nitric oxide bound to the catalytic centre, which restores electron transport, accelerates proton pumping across the inner mitochondrial membrane (increasing the mitochondrial membrane potential / charge gradient), and increases ATP synthesis.

• supports: Proposed Mechanisms of Photobiomodulation or Low-Level Light Therapy. (IEEE journal of selected topics in quantum electronics : a publication of the IEEE Lasers and Electro-optics Society 2016) · cited 1612x in the literature

  "One of the most important chromophores is cytochrome c oxidase (unit IV in the mitochondrial respiratory chain), which contains both heme and copper centers and absorbs light into the near-infra-red region. The leading hypothesis is that the photons dissociate inhibitory nitric oxide from the enzyme, leading to an increase in electron transport, mitochondrial membrane potential and ATP production." (abstract, results, passage verified)

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• supports: Molecular Mechanisms of Photobiomodulation in Retinal Diseases: Cytochrome c Oxidase, Mito… (International journal of molecular sciences 2026)

  "At the molecular level, PBM acts primarily through photon absorption by cytochrome c oxidase (CcO, complex IV of the mitochondrial electron transport chain), whose four metal centres-two copper (CuA and CuB) and two heme groups (heme a and heme a 3 )-absorb light across approximately 600-1000 nm. Photon capture promotes photodissociation of inhibitory nitric oxide (NO) from the binuclear CuB-heme a 3 centre, accelerates electron transfer, restores the proton-motive force and increases ATP synthesis." (abstract, results, passage verified)

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Dr. Martin Picard published a paper on the energy resistance principle, proposing that disease fundamentally arises when mitochondrial energy resistance and electron flow deviate from an optimal homeostatic zone.

"Dr. Martin Picard out of Columbia University, he's published a great paper with his wife Nirosha where it's called the energy resistance principle. If we have too much energy resistance in a system, if energy cannot flow properly, that's what is fundamentally at the root cause of every single disease. If energy resistance is too high, you have disease. If energy resistance is too low, you also have disease." (said at 0:11:13)

Dr. Martin Picard and colleagues published a 2025 review article in Cell Metabolism titled 'The energy resistance principle.' The paper outlines the Energy Resistance Principle (ERP), proposing that energy resistance (éR) regulates biological energy transformation from food-derived electron flux to oxygen. The authors propose that while a baseline level of resistance is essential to capture energy for cellular work, excess resistance drives reductive and oxidative stress, inflammation, and molecular damage characteristic of aging and disease, framing bioenergetic resistance along a health-disease continuum. Because this represents a theoretical conceptual framework and narrative review rather than empirical clinical trial data, the GRADE certainty for the principle itself is very low.

• supports: The energy resistance principle. (Cell metabolism 2025) · cited 12x in the literature

  "The energy resistance principle (ERP) describes behavior and transformation of energy in the carbon-based circuitry of biology. We show how energy resistance (éR) is the fundamental property that enables transformation, converting into useful work the unformed energy potential of food-derived electrons fluxing toward oxygen. Although éR is required to sustain life, excess éR directly causes reductive and oxidative stress, heat, inflammation, molecular damage, and information loss-all hallmarks of disease and aging." (abstract, results)

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A study by Glen Jeffery showed that shining red light on 4% of participants' backs after glucose ingestion resulted in an almost 30% reduction in total blood glucose levels compared to controls.

"There was a great paper published by Dr. Glen Jeffery where he basically shined red light on participants. He basically gave these participants a big gulp of glucose. So, a big bottle of glucose, they drank the glucose, he shined red light on 4% of the total body surface area, so a very small portion of these people's backs. And he monitored their blood glucose over time... compared to the control group, the people who got shined the red light on their backs had an almost 30% reduction in total blood glucose levels" (said at 0:13:23)

The claim accurately describes the findings of a 2024 study led by Glen Jeffery's laboratory (Powner et al., PMID 38378043). In healthy participants undergoing an oral glucose tolerance test, a 15-minute exposure of dorsal skin to 670 nm red light reduced the post-challenge integrated blood glucose elevation by 27.7% (almost 30%) over two hours compared to the unexposed control condition, with a 7.5% reduction in peak glucose spike. GRADE certainty is rated low because this is a single preliminary study with a small sample size.

• supports: Light stimulation of mitochondria reduces blood glucose levels. (Journal of biophotonics 2024) · cited 27x in the literature

  "A 15 min exposure to 670 nm light reduced the degree of blood glucose elevation following glucose intake by 27.7%, integrated over 2 h after the glucose challenge. Maximum glucose spiking was reduced by 7.5%." (abstract, results)

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A study by Glen Jeffery in bees found that red light exposure reduced blood glucose levels, whereas blue light exposure increased blood glucose levels compared to controls.

"Glen Jeffery also, before he did this paper with the participants where shining the red light on their backs, he first did it on bees cuz he didn't want to go straight into humans. So, he took bees, he had three groups. He had a control group, he had a red light group, and then he had a blue light group. What he saw is that compared to the control group, the red light group had a blunted glucose, reduced blood glucose in the bees. When he looked at the blue light group, there was an increase in blood glucose from shining the blue light on these bees." (said at 0:15:18)

The speaker accurately describes a 2022 study by Glen Jeffery's research group using a bumblebee model. In the study, bees received a glucose challenge and were exposed to control conditions, 670 nm (red) light, or 420 nm (blue) light. Exposure to 670 nm red light resulted in a significant 50% reduction in circulating glucose concentration, whereas 420 nm blue light exposure increased systemic glucose levels by over 50% compared to baseline. Because this evidence is derived entirely from an insect model, the GRADE certainty is very low.

• supports: Systemic glucose levels are modulated by specific wavelengths in the solar light spectrum … (PloS one 2022) · cited 12x in the literature

  "Increasing mitochondrial activity with 670 nm light at the peak of circulating glucose, resulted in a significant 50% reduction in concentration measured. Exposure to 420nm light that retards mitochondrial respiration elevated systemic glucose levels by over 50%." (abstract, results, passage verified)

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A study by Glen Jeffery published in Scientific Reports demonstrated that placing a 60-W incandescent bulb on participants' desks in an LED-only environment for two weeks improved visual function/color contrast by almost 30%.

"another study by Glen Jeffery published in Nature, one of the most prestigious journals out there, Nature Scientific Reports... He took a 60-W incandescent light bulb, he placed it on these participants' desks... And he put it on for two weeks. So, 60-W incandescent light bulb for two weeks. He tested their color contrast. So, color contrast is essentially sort of this function to see visual function... And what he saw was an almost 30% improvement in these participants' visual function simply by adding a 60-W incandescent light bulb on their desk." (said at 0:19:44)

Glen Jeffery and colleagues published a study in Scientific Reports examining the impact of supplementing standard LED lighting environments with broad-spectrum light (400-1500+ nm, such as incandescent light) for 2 weeks. The authors found significant improvements in cone-mediated color contrast sensitivity that persisted after the intervention was removed.

• supports: LED lighting (350-650nm) undermines human visual performance unless supplemented by wider … (Scientific reports 2026) · cited 1x in the literature

  "Here we supplement LED light with broad spectrum lighting (400–1500 nm+) for 2 weeks and test colour contrast sensitivity. We show significant improvement in this metric that last for 2 months after the supplemental lighting is removed." (abstract)

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Standard commercial LED lighting emits light that drops off at around 700 nanometers and contains virtually no near-infrared or far-infrared radiation.

"when we look at the LED light spectrum, there's a huge spike in the blue, there's some, you know, some green, some orange, some red, and then it stops at around 700 nanometers, which is when the visual spectrum sort of stops. And then beyond that is infrared, near-infrared and far-infrared, and these LED lights have none of that, right?" (said at 0:19:44)

Standard commercial white LED lighting operates via a blue-emitting diode (typically GaN-based, ~450 nm) coated with phosphor materials that convert part of the blue light into broad visible wavelengths (green, yellow, red), sharply attenuating near 700 nm. Unlike thermal sources such as sunlight or incandescent bulbs, commercial white LEDs emit light confined to the human visible spectrum and do not emit meaningful near-infrared or far-infrared radiation.

• supports: Advantages of white LED lamps and new detector technology in photometry (Light Science & Applications 2015) · cited 218x in the literature

  "Because the spectra of white LEDs are limited to the visible wavelength range, a novel method for the realization of photometric units based on the predictable quantum efficient detector (PQED) can be utilized." (abstract, passage verified)

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Retinal tissue has the highest concentration of mitochondria of any tissue in the human body.

"our eyes, our retina, is the tissue in our body that has the most mitochondria. So, our retina are very mitochondrial dense. The reason for that is because they need to function a lot, so they need a lot of energy. And so, the mitochondria are providing that." (said at 0:21:01)

Published literature confirms that retinal tissue, particularly its photoreceptor cells, has the highest density of mitochondria of any tissue or cell type in the body to meet its exceptionally high metabolic and energy demands.

• supports: Dyslipidemia in retinal metabolic disorders. (EMBO molecular medicine 2019) · cited 95x in the literature

  "The light-sensitive photoreceptors in the retina are extremely metabolically demanding and have the highest density of mitochondria of any cell in the body." (abstract, results, passage verified)

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• supports: Near infrared spectroscopy reveals instability in retinal mitochondrial metabolism and hae… (Journal of biophotonics 2022) · cited 10x in the literature

  "Mitochondrial density is highest in the retina, and they exhibit a prominent optical absorption around 420 nm arising from the Soret band of their porphyrins, including in cytochrome-c-oxidase in their respiratory chain." (abstract)

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• supports: VDAC in Retinal Health and Disease. (Biomolecules 2024) · cited 9x in the literature

  "The retina is unique in that it is continuously exposed to light and has the highest metabolic rate and demand for energy amongst all the tissues in the body." (abstract, passage verified)

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Glen Jeffery previously demonstrated that shining a narrow-band 670-nm red light into human eyes improved visual function by approximately 15%.

"Glen Jeffery has also—he published some research earlier where he shined a red light device, just simply a 670-nm red light, in participants' eyes. And he also saw an improvement in visual function. Now, keep in mind that's just a narrow-band, single-wavelength red light. That percentage of improvement was around, I want to say, 15%." (said at 0:21:27)

Glen Jeffery and colleagues (Shinhmar et al., 2020; PMID 32596723) published research demonstrating that exposing human eyes to narrow-band 670-nm deep-red light (3 minutes daily for 2 weeks) significantly improved photoreceptor performance in participants aged 40 and older. Specifically, color contrast sensitivity along the tritan (blue) axis improved by approximately 17–20%, alongside significant improvements in scotopic rod dark-adaptation thresholds. The GRADE certainty is low due to the small sample size (n=24) and preliminary nature of the pilot intervention.

• supports: Optically Improved Mitochondrial Function Redeems Aged Human Visual Decline. (The journals of gerontology. Series A, Biological sciences and medical sciences 2020) · cited 51x in the literature

  "Here, we use 670-nm light to improve photoreceptor performance and measure this psychophysically in those aged 28-72 years. Rod and cone performance declined significantly after approximately 40 years of age. 670-nm light had no impact in younger individuals, but in those around 40 years and older, significant improvements were obtained in color contrast sensitivity for the blue visual axis (tritan) known to display mitochondrial vulnerability." (abstract, results, passage verified)

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Exposing cultured cells in vitro to blue light causes an increase in reactive oxygen species.

"if we shine blue light on cells in a petri dish, we see an increase in reactive oxygen species. Reactive oxygen species are these reactive molecules, these free radicals that basically cause damage if they're in excess in our body. They cause damage to our cells. And when we shine blue light, you have an increase in reactive oxygen species." (said at 0:23:44)

The claim is supported by in vitro experimental literature. Exposure of various cultured mammalian cell lines (such as retinal pigment epithelial cells and retinal ganglion cells) to blue light consistently demonstrates a marked increase in intracellular and mitochondrial reactive oxygen species (ROS). Because the evidence base consists of in vitro cell culture and preclinical laboratory models, the GRADE certainty is rated as very low.

• supports: Differential protective effects of blue light (BL)-exposed retinal pigment epithelial cell… (Experimental eye research 2026)

  "Exposure of RPE cells to BL significantly increased the levels of cellular ROS and mitochondrial superoxide anion." (abstract, results, passage verified)

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• supports: Blue Light Induces Retinal Ganglion Cell Damage by Stimulating Drp1-Dependent Mitochondria… (Investigative ophthalmology & visual science 2026)

  "This disruption promoted the nuclear translocation and phosphorylation of p65, which subsequently enhanced NOX4 transcription and increased mitochondrial reactive oxygen species (ROS) production." (abstract, results, passage verified)

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Exposing the body to red and infrared light stimulates the production of endogenous antioxidants that counteract reactive oxygen species.

"when we shine red and infrared light, it creates and it produces antioxidants within the body which then are able to combat those reactive oxygen species." (said at 0:24:05)

Photobiomodulation (PBM) using red and near-infrared light (typically in the 600–1000 nm range) is well-documented to stimulate the endogenous antioxidant defense system. Mechanistically, photon absorption by mitochondrial cytochrome c oxidase triggers transient signaling reactive oxygen species (ROS) that activate the Nrf2/Keap1/ARE pathway, upregulating endogenous antioxidant enzymes including superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), and heme oxygenase-1 (HO-1). Both preclinical and randomized human clinical trials consistently demonstrate increased levels of endogenous antioxidants (such as glutathione and SOD) and reduced markers of oxidative stress following red and near-infrared light exposure.

• supports: The effect of low-level laser therapy on the oxidative stress level and quality of life in… (Free radical research 2024) · cited 4x in the literature

  "Improvements in glutathione levels and quality of life were significantly higher in the active treatment group than in the sham-controlled group. LLLT was found to be more effective on OS and quality of life in patients with HT than in patients in the sham-controlled group." (abstract, results, passage verified)

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• supports: Effects of Low-Level Light Therapy (LLLT) on Oxidative Stress in the Cutaneous Healing Pro… (Journal of lasers in medical sciences 2026)

  "Nine studies were included, and all the articles presented significant modulation of oxidative stress, with reductions in oxidizing markers (superoxide anion) and apoptosis activators (cytochrome c), and mainly, increases in antioxidant enzymatic defense (catalase, superoxide dismutase, and glutathione peroxidase)." (abstract, results, passage verified)

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• supports: Molecular Mechanisms of Photobiomodulation in Retinal Diseases: Cytochrome c Oxidase, Mito… (International journal of molecular sciences 2026)

  "These primary events trigger a coordinated molecular programme that includes (i) transient mitochondrial reactive oxygen species (ROS) bursts that activate the Nrf2/Keap1/ARE axis and upregulate phase II antioxidant enzymes (HO-1, NQO1, GCLC, SOD2, catalase, GPx)" (abstract, results, passage verified)

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Observational cohort studies show that increased sun exposure increases the risk of developing basal cell and squamous cell carcinomas.

"when we look at the observational studies on this, we do see an association where if we do increase sun exposure, we do increase these the risks of getting these basal cell and squamous cell carcinomas." (said at 0:34:06)

Observational cohort studies and systematic reviews consistently demonstrate that increased solar ultraviolet (UV) radiation and cumulative sun exposure (as well as severe sunburns) are associated with elevated risks of developing both basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (SCC).

• supports: Patterns of Ultraviolet Radiation Exposure and Skin Cancer Risk: the E3N-SunExp Study. (Journal of epidemiology 2018) · cited 149x in the literature

  "A history of severe sunburns <25 years was associated with increased risks of all skin cancers (melanoma: OR 2.7; BCC: OR 1.7; SCC: OR 2.0 for ≥6 sunburns vs. none), while sunburns ≥25 years were associated with BCC and SCC only. While high-sun protection factor sunscreen use before age 25 was associated with lower BCC risk (P trend = 0.02), use since age 25 and reapplication of sunscreen were associated with higher risks of all three types of skin cancer. There were positive linear associations between total UV score and risks of BCC (P trend = 0.01) and SCC (P trend = 0.09), but not melanoma." (abstract, results)

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• supports: Global evidence on occupational sun exposure and keratinocyte cancers: a systematic review… (The British journal of dermatology 2021) · cited 89x in the literature

  "Eighteen of the 19 studies reported effect estimates suggesting an increased risk of basal cell carcinoma (BCC) and/or squamous cell carcinoma (SCC) among outdoor workers." (abstract, results, passage verified)

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DNA repair mechanisms and tumor suppressor genes in the human body are regulated by circadian biology.

"our our DNA repair mechanisms and our tumor suppressor genes in our body are all under circadian control." (said at 0:34:40)

Preclinical and mechanistic molecular biology studies demonstrate that the circadian clock directly modulates major DNA repair pathways (including nucleotide excision repair and transcription-coupled repair) and regulates key tumor suppressor networks such as p53 (via direct interactions with core clock factors like PER2 and CRY2). While stating that 'all' such genes are under clock control is a broad colloquial generalization, the regulatory relationship between circadian biology, DNA repair mechanisms, and tumor suppressors is well established.

• supports: The circadian factor Period 2 modulates p53 stability and transcriptional activity in unst… (Molecular biology of the cell 2014) · cited 132x in the literature

  "Overall our findings place hPer2 directly at the heart of the hp53-mediated response by ensuring that basal levels of hp53 are available to precondition the cell when a rapid, hp53-mediated, transcriptional response is needed." (abstract, passage verified)

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• supports: The tumour suppressing role of the circadian clock. (IUBMB life 2019) · cited 35x in the literature

  "This review summarises the important role the circadian system plays in regulating cellular processes, including the cell cycle, apoptosis, DNA repair, the epithelial-to-mesenchymal transition, metabolism and immunity and how its dysregulation has widespread implications and could be a critical player in the development of cancer." (abstract, passage verified)

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A significant number of melanoma cases occur on anatomical sites that do not receive sun exposure, such as the waist, palms, and soles of the feet.

"a lot of melanoma cases are actually in parts of the body that don't even receive sun exposure. So, think like the the waist area. Think like the palms of your hands, the bottom of your feet. Like people are getting melanoma in areas that don't even get any sun exposure." (said at 0:36:37)

Epidemiological evidence confirms that a meaningful proportion of melanomas develop on anatomical sites with little to no sun exposure, including the palms, soles of the feet, and subungual sites (acral lentiginous melanoma), as well as mucosal and uveal sites. Overall, approximately 10% of all primary melanomas occur on sun-shielded or non-sun-exposed areas, and in populations with darker skin phototypes, these non-sun-exposed subtypes represent the predominant form of melanoma.

• supports: Sun exposure and melanomas on sun-shielded and sun-exposed body areas. (Advances in experimental medicine and biology 2014) · cited 19x in the literature

  "About 10% of primary melanomas arise from sites not exposed to sun. Acral lentiginous melanoma, mucosal melanoma (in the oral cavities, nasal sinuses, genital tract and rectum) and uveal melanoma are all on non-sun-exposed tissues." (abstract, passage verified)

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• supports: Characteristics, rates, and trends of melanoma incidence among Hispanics in the USA. (Cancer causes &amp; control : CCC 2016) · cited 45x in the literature

  "Results suggest Hispanics and providers need education to increase awareness about the characteristics of melanoma among Hispanics, including types that occur on non-sun-exposed areas (ALM and NM)." (abstract, conclusions, passage verified)

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In a 20-year Swedish cohort study of 30,000 women, higher sun exposure was associated with a dose-dependent reduction in all-cause mortality.

"They took 30,000 Swedish women... tracked these women for 20 years and what they saw at the end of it was that the women that got the most amount of sun exposure had the lowest mortality rate... What's really interesting here is that it was dose-dependent." (said at 0:37:55)

The speaker accurately describes the findings of the Melanoma in Southern Sweden (MISS) cohort study led by Dr. Pelle Lindqvist. The prospective study followed 29,518 Swedish women for approximately 20 years (recruited 1990-1992) and found an inverse, dose-dependent relationship between sun exposure habits and all-cause mortality, with the lowest mortality observed in women with the highest sun exposure habits. Because this is observational prospective cohort data subject to potential residual confounding (such as general physical activity and socioeconomic factors), the GRADE certainty is rated as low.

• supports: Avoidance of sun exposure is a risk factor for all-cause mortality: results from the Melan… (Journal of internal medicine 2014) · cited 114x in the literature

  "We assessed the avoidance of sun exposure as a risk factor for all-cause mortality for 29 518 Swedish women in a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort... We found that all-cause mortality was inversely related to sun exposure habits. The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group" (abstract, methods and results)

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• supports: Avoidance of sun exposure as a risk factor for major causes of death: a competing risk ana… (Journal of internal medicine 2016) · cited 149x in the literature

  "Women with active sunlight exposure habits experience a lower mortality rate than women who avoid sun exposure... We assessed the differences in sun exposure as a risk factor for all-cause mortality in a competing risk scenario for 29 518 Swedish women in a prospective 20-year follow-up of the Melanoma in Southern Sweden (MISS) cohort." (abstract, background and methods)

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In the Swedish cohort study, women with high sun exposure who smoked had the same mortality rate as women who avoided sun exposure and did not smoke.

"what they saw was that the women who got the most amount of sun exposure and smoked had the same mortality as women who got the least amount of sun exposure and did not smoke." (said at 0:39:15)

In the Melanoma in Southern Sweden (MISS) prospective cohort study of 29,518 women followed for 20 years (Lindqvist et al., 2016), nonsmokers who avoided sun exposure were found to have a life expectancy and mortality profile comparable to smokers in the highest sun exposure group. Because this finding originates from an observational cohort subject to potential residual confounding, the certainty of evidence is low according to GRADE.

• supports: Avoidance of sun exposure as a risk factor for major causes of death: a competing risk ana… (Journal of internal medicine 2016) · cited 149x in the literature

  "Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking." (abstract, results, passage verified)

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Analysis of 400,000 UK Biobank participants showed a dose-response reduction in mortality with higher sun exposure.

"Dr. Richard Weller took this and he took uh UK Biobank data. 400,000 participants... And what he saw was the exact same thing. Dose-response curve, the more sun exposure people got, the lower their mortality was." (said at 0:39:50)

A 2024 cohort analysis of UK Biobank participants led by Richard Weller and colleagues evaluated ultraviolet (UV) light exposure (measured via annual average residential solar radiation and solarium use) and subsequent mortality. The study found that higher UV exposure was inversely associated with all-cause, cardiovascular disease, and cancer mortality in a dose-dependent fashion.

• supports: Higher ultraviolet light exposure is associated with lower mortality: An analysis of data … (Health &amp; place 2024) · cited 21x in the literature

  "The UV exposures were inversely associated with all-cause, cardiovascular disease (CVD) and cancer mortality. Solarium users were also at a lower risk of non-CVD/non-cancer mortality. The benefits of UV exposure may outweigh the risks in low-sunlight countries." (abstract, results, passage verified)

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In a preprint by Dr. Richard Weller, statistical modeling indicated that for every 1 skin cancer death prevented by reducing sun exposure, 75 lives are lost from cardiovascular disease and non-skin cancers.

"if we were to put everybody in the high UV category and we put them into the low UV category, so we made them get less sun exposure, for every one life that we would save from a skin cancer death... we would lose 75 lives from cardiovascular disease and non-skin cancer cancers." (said at 0:42:20)

The speaker accurately describes the modeling findings from Dr. Richard Weller and colleagues' UK Biobank cohort investigation (initially released as a preprint and subsequently published in Health & Place, PMID: 39094281). In their risk-benefit modeling of moving individuals between UV exposure categories, the authors estimated that the reduction in cardiovascular and non-skin cancer deaths with higher UV exposure vastly exceeds the increase in skin cancer mortality (calculating approximately 75 to 80 non-skin cancer and cardiovascular lives lost for every 1 skin cancer death prevented by shifting to low UV exposure). Because this is observational epidemiology and statistical modeling subject to potential confounding, the overall certainty of evidence is low.

• supports: Higher ultraviolet light exposure is associated with lower mortality: An analysis of data … (Health &amp; place 2024) · cited 21x in the literature

  "The UV exposures were inversely associated with all-cause, cardiovascular disease (CVD) and cancer mortality. Solarium users were also at a lower risk of non-CVD/non-cancer mortality. The benefits of UV exposure may outweigh the risks in low-sunlight countries." (abstract, results, passage verified)

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UVA light mobilizes stored nitric oxide from the dermis of the skin into the bloodstream.

"in our dermis of the skin, we have nitric oxide stores. So, our our skin stores nitric oxide. And when UVA light, or UV light in general, is shined on our skin, these nitric oxide molecules get mobilized, and they are able to now go into the bloodstream" (said at 0:44:40)

The speaker's statement accurately reflects human experimental research. Controlled human studies demonstrate that human skin contains pre-formed stores of nitric oxide (NO) metabolites and that exposure to UVA light mobilizes NO bioactivity from cutaneous stores into the systemic circulation independently of nitric oxide synthase (NOS) activity, increasing circulating nitrite and causing vasodilation.

• supports: UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure i… (The Journal of investigative dermatology 2014) · cited 286x in the literature

  "UVA irradiation of the forearm caused increased blood flow independently of NO synthase (NOS) activity, suggesting involvement of pre-formed cutaneous NO stores." (abstract, results, passage verified)

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Randomized controlled human trials by Dr. Richard Weller demonstrate that shining UVA light on skin increases blood nitric oxide levels and lowers blood pressure.

"He he has he has a clinical uh uh randomized placebo-controlled trials in in humans, where he shines UVA light on participants. He measured blood nitric oxide levels, blood nitric oxide levels increase, he measures blood pressure, blood pressure drops." (said at 0:45:15)

Dr. Richard Weller and colleagues published a randomized human crossover trial demonstrating that whole-body UVA irradiation mobilizes cutaneous nitric oxide stores into the systemic circulation (manifested as an increase in circulating plasma nitrite concentrations) and causes a significant reduction in systemic blood pressure.

• supports: UVA irradiation of human skin vasodilates arterial vasculature and lowers blood pressure i… (The Journal of investigative dermatology 2014) · cited 286x in the literature

  "In 24 healthy volunteers, irradiation of the skin with two standard erythemal doses of UVA lowered blood pressure (BP), with concomitant decreases in circulating nitrate and rises in nitrite concentrations." (abstract, results, passage verified)

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UV light causes DNA breaks in skin cells, which activates p53 to bind DNA and produce the prohormone pro-opiomelanocortin (POMC).

"when UV light hits the skin, it does break DNA. So, DNA gets broken and via that broken DNA our body produces P53... P53, it will bind to our DNA to produce this prohormone, this pro-opiomelanocortin, POMC for short." (said at 0:48:40)

The speaker accurately describes the established molecular pathway of UV-induced pigmentation and POMC production. UV radiation causes DNA damage in epidermal keratinocytes, activating the p53 transcription factor, which directly binds to the promoter of the pro-opiomelanocortin (POMC) gene to stimulate POMC expression. POMC is subsequently cleaved into peptides such as alpha-MSH (which stimulates melanin production) and beta-endorphin.

• supports: Central role of p53 in the suntan response and pathologic hyperpigmentation. (Cell 2007) · cited 644x in the literature

  "UV-induced pigmentation (suntanning) requires induction of alpha-melanocyte-stimulating hormone (alpha-MSH) secretion by keratinocytes. alpha-MSH and other bioactive peptides are cleavage products of pro-opiomelanocortin (POMC). Here we provide biochemical and genetic evidence demonstrating that UV induction of POMC/MSH in skin is directly controlled by p53. Whereas p53 potently stimulates the POMC promoter in response to UV, the absence of p53, as in knockout mice, is associated with absence of the UV-tanning response." (abstract, passage verified)

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• supports: Skin pigmentation and its control: From ultraviolet radiation to stem cells. (Experimental dermatology 2021) · cited 193x in the literature

  "The delayed tanning pathway occurs as UVB produces keratinocyte DNA damage, causing p53-mediated expression of the pro-opiomelanocortin (POMC) gene that is processed to release alpha-melanocyte-stimulating hormone (alpha-MSH)." (abstract)

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Pro-opiomelanocortin (POMC) produced in response to UV light is cleaved into beta-endorphin.

"And then POMC gets cleaved, so our body basically cuts POMC up at specific areas. It gets cleaved into other peptides. And one of the peptides is beta-endorphin and beta-endorphin is an endogenous opioid." (said at 0:49:15)

Pro-opiomelanocortin (POMC) is a precursor polypeptide that is induced in epidermal keratinocytes following UV radiation (via a p53-dependent pathway). It is subsequently cleaved by prohormone convertases into several biologically active peptide derivatives, including melanocyte-stimulating hormone (alpha-MSH) and the endogenous opioid beta-endorphin.

• supports: Central role of p53 in the suntan response and pathologic hyperpigmentation. (Cell 2007) · cited 644x in the literature

  "alpha-MSH and other bioactive peptides are cleavage products of pro-opiomelanocortin (POMC). Here we provide biochemical and genetic evidence demonstrating that UV induction of POMC/MSH in skin is directly controlled by p53... The same pathway produces beta-endorphin, another POMC derivative, which potentially contributes to sun-seeking behaviors." (abstract, passage verified)

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• supports: Skin &#x3b2;-endorphin mediates addiction to UV light. (Cell 2014) · cited 295x in the literature

  "Following UV exposure, epidermal keratinocytes synthesize proopiomelanocortin (POMC) that is processed to melanocyte-stimulating hormone, inducing tanning. We show that, in rodents, another POMC-derived peptide, β-endorphin, is coordinately synthesized in skin, elevating plasma levels after low-dose UV." (abstract, passage verified)

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Morning sunlight entering the eyes stimulates the HPA axis to produce a higher cortisol awakening response peak.

"Now, the way we spike that cortisol more is to get morning sunlight. So if you can get morning sunlight into the eyes, it has an effect on our hypothalamic-pituitary-adrenal axis, our HPA axis, and that is allowing our body to produce more cortisol in the morning, having a higher spike." (said at 0:54:26)

Multiple controlled laboratory studies demonstrate that ocular exposure to morning bright light and short-wavelength (blue) light stimulates the hypothalamic-pituitary-adrenal (HPA) axis, leading to a significantly higher cortisol awakening response (CAR) and peak morning cortisol levels compared to dim light or red light controls.

• supports: The effects of post-awakening light exposure on the cortisol awakening response in healthy… (Psychoneuroendocrinology 2019) · cited 38x in the literature

  "Specifically, an increased CAR was found after exposure to bright (vs. dim) light (study I; (F (3.7, 106.4) = 11.93, p < .001, η² p = .29) and following blue and green (vs. red) light exposure (study II; F (4.9, 194.6) = 2.49, p = .037, η² p = .10). Our findings illustrate the crucial role of light intensity and wavelength for expression of the CAR, in line with current theoretical knowledge of underlying neurobiological mechanisms." (abstract, results)

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• supports: Increase in cortisol concentration due to standardized bright and blue light exposure on s… (Stress (Amsterdam, Netherlands) 2021) · cited 20x in the literature

  "This study shows that bright light and blue light affect the cortisol response in contrast to dim light and red light conditions. The HPA axis showed a stimulatory effect by bright versus dim light and different wavelengths of light exposure." (abstract, results, passage verified)

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Intrinsically photosensitive retinal ganglion cells express melanopsin to drive the central circadian clock and cortisol regulation pathways.

"which then stimulates your intrinsically photosensitive retinal ganglion cells, which have melanopsin in them, and you have this whole pathway in your brain that produces cortisol and basically controls every single one of your cells." (said at 0:56:10)

The speaker's statement accurately describes established circadian neurobiology. Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin, detecting environmental light and transmitting signals along the retinohypothalamic tract directly to the suprachiasmatic nucleus (SCN), the master circadian pacemaker in the brain. The SCN coordinates neuroendocrine rhythms—including the hypothalamic-pituitary-adrenal axis regulating cortisol production—and synchronizes cell-autonomous peripheral clocks across peripheral tissues.

• supports: Clinical Chronobiology: Circadian Rhythms in Health and Disease. (Seminars in neurology 2025) · cited 17x in the literature

  "The suprachiasmatic nucleus (SCN) in the hypothalamus is the mammalian master clock that synchronizes all other tissue-specific peripheral clocks, primarily through gamma-aminobutyric acid (GABA) and vasoactive intestinal polypeptide (VIP). The SCN follows Earth's 24-hour cycle by light entrainment through the retinohypothalamic tract." (abstract, results, passage verified)

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• supports: Retinal light perception and biological rhythms: The role of light in sleep and mood from … (Molecular medicine reports 2026) · cited 5x in the literature

  "Beyond its canonical function in image formation, the retina operates as a primary irradiance detector through a specialized class of neurons, the intrinsically photosensitive retinal ganglion cells (ipRGCs), which utilize the photopigment melanopsin. These cells convey environmental light information directly to the suprachiasmatic nucleus (SCN), the brain's master circadian pacemaker, thereby synchronizing the body's internal timekeeping with the external solar cycle." (abstract, results, passage verified)

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Cortisol follows a circadian rhythm and fluctuates throughout the day.

"cortisol again has a circadian rhythm, so it fluctuates throughout the day." (said at 1:01:12)

Cortisol exhibits a well-established diurnal circadian rhythm under the control of the central circadian pacemaker (the suprachiasmatic nucleus) and the hypothalamic-pituitary-adrenal axis. In healthy individuals, cortisol levels peak sharply in the early morning shortly after waking (cortisol awakening response) and gradually decline throughout the day to a nadir around midnight.

• supports: "Feeding the Rhythm"-Effects of Food and Nutrients on Daily Cortisol Secretion: From Molec… (International journal of molecular sciences 2025) · cited 2x in the literature

  "Cortisol secretion exhibits one of the largest endocrine amplitudes, with an early morning peak and late-evening nadir driven by the suprachiasmatic nucleus and hypothalamus-pituitary-adrenal axis, representing the most robust endocrine output of the circadian system." (abstract, passage verified)

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The physiological sigh (a deep inhale followed by a second quick inhale and a slow, soft exhale) lowers heart rate and reduces acute stress.

"Before I did that presentation, I did what's called the physiological sigh. So, it's a deep inhale in followed by another sort of squeeze in that inhale, as much more as you can get in, and then a very soft slow exhale out, sort of lowering your heart rate, destressing you in that scenario." (said at 1:04:00)

Randomized trials demonstrate that the physiological sigh (cyclic sighing, characterized by two sequential inhales followed by a prolonged, slow exhalation) effectively reduces acute state anxiety, improves mood, and lowers physiological arousal compared to controls or mindfulness meditation.

• supports: Brief structured respiration practices enhance mood and reduce physiological arousal. (Cell reports. Medicine 2023) · cited 276x in the literature

  "Using a mixed-effects model, we show that breathwork, especially the exhale-focused cyclic sighing, produces greater improvement in mood (p < 0.05) and reduction in respiratory rate (p < 0.05) compared with mindfulness meditation. Daily 5-min cyclic sighing has promise as an effective stress management exercise." (abstract, results)

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• supports: Simply breathing anxiety away? A pilot, just-in-time ecological momentary intervention stu… (Anxiety, stress, and coping 2026)

  "During acute threat situations, 47 participants completed a short questionnaire assessing state anxiety. They were subsequently assigned to one of three conditions: box breathing, cyclic sighing or a passive control condition. Five minutes later, state anxiety and attention were measured. Compared with the control condition, both box breathing and cyclic sighing were associated with greater reductions in state anxiety." (abstract, results, passage verified)

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