HoldsUp

Mark Hyman, MD · 2026-05-20 · Mark Hyman (host), Shanna Swan

Microplastics Are Inside Your Body Right Now — Here's What They're Doing

34 research-tied claims examined: 3 overstated 4 context 25 supported 2 unverified

25

Supported by research

0:04:35Shanna Swansupportedhigh

The Carlsen study out of Denmark claimed that human sperm counts had declined by 50% over a 50-year period.

"The first thing they asked me to do was to look at a study out of Denmark that claimed that sperm count had declined 50% in 50 years. Yeah, that was the Carlsen paper." (said at 0:04:35)

The speaker accurately describes the landmark 1992 meta-analysis by Elisabeth Carlsen and colleagues from the University of Copenhagen (Denmark), published in the BMJ. The study reviewed 61 papers published between 1938 and 1991 (comprising 14,947 men) and reported that mean sperm concentration declined from 113 million/mL in 1940 to 66 million/mL in 1990 (a 42% drop in density), alongside a decrease in seminal volume from 3.40 mL to 2.75 mL, yielding an overall decline in total sperm count per ejaculate of over 50% across the 50-year span.

0:05:08Shanna Swansupportedmoderate

A reanalysis of 61 studies controlling for smoking, obesity rates, and sperm counting methods confirmed the 50-year sperm count decline trend.

"So, we looked at things that might explain it, like are there changes in smoking, changes in obesity rates, changes in how sperm count was measured, and so on and so forth. And we put all these variables into a large model—61 studies, we got all the data from—put it in a big model, ran the model, and then the big surprise was that that didn't change anything." (said at 0:05:08)

In 1997, Swan et al. published a reanalysis of the 61 studies originally analyzed by Carlsen et al. (1992), which had reported a ~50% worldwide decline in sperm density between 1938 and 1990. The reanalysis examined potential confounding and methodological variables—including specimen collection and counting methods, abstinence duration, age, fertility status, study location, and region—and found that controlling for these variables did not eliminate the significant downward trend in sperm density in the United States and Europe over the ~50-year period.

0:06:39Shanna Swansupportedhigh

CDC NHANES biomonitoring data detected phthalates in nearly 100% of a representative sample of the US population.

"First of all, he said they were in everyone in the United States as far as they could determine at CDC because they had the NHANES study that sampled a representative sample of the US population, and you could see that it was positive. It was detected in the sample almost 100%." (said at 0:06:39)

Biomonitoring data from the CDC's National Health and Nutrition Examination Survey (NHANES), which examines a nationally representative sample of the U.S. population, shows ubiquitous exposure to phthalates. Analyses of NHANES samples demonstrate that major urinary phthalate metabolites are detected in nearly the entire sampled population (individual phthalate metabolites detected in 75% to 100% of participants, and at least one phthalate metabolite detected in 99–100% of individuals across demographic groups).

0:07:05Shanna Swansupportedvery low

National Toxicology Program studies showed that prenatal exposure to phthalates causes male rodent offspring to develop less male-typical genital tracts, known as 'the phthalate syndrome.'

"he said that his colleagues in the National Toxicology Program had shown that when a pregnant rodent, rat or mouse, was exposed to phthalates, that their male offspring developed atypically. And what they did was they had a less male-typical genital tract, and we can talk about that some more. I'm sure we will. But they gave this the name 'the phthalate syndrome.'" (said at 0:07:05)

Extensive experimental toxicology research, notably led by researchers associated with the National Toxicology Program (NTP) and U.S. EPA, established that in utero exposure to specific phthalate esters impairs fetal Leydig cell testosterone and insulin-like peptide 3 (INSL3) production in male rodents. This suppression of androgen signaling disrupts normal male sexual differentiation, leading to a cluster of reproductive tract abnormalities (such as shortened anogenital distance, hypospadias, cryptorchidism, and underdeveloped reproductive organs) formally termed 'the phthalate syndrome.' Because this claim is based on animal models, the certainty of evidence is graded as very low under GRADE criteria.

0:08:36Shanna Swansupportedlow

Research by Dr. Shanna Swan demonstrated the occurrence of the phthalate syndrome in human male infants.

"but I did find the phthalate syndrome in humans." (said at 0:08:36)

Research led by Dr. Shanna Swan provided the first epidemiological evidence linking prenatal phthalate exposure to genital alterations in human male infants characteristic of the rodent 'phthalate syndrome'. In a landmark 2005 prospective study of mother-son pairs, higher maternal urinary concentrations of several phthalate metabolites (including MEP, MBP, MBzP, and MiBP) were significantly associated with shorter anogenital index (AGI), smaller penile volume, and incomplete testicular descent in male infants. These associations were subsequently replicated in larger multi-center cohorts (such as the TIDES study). Because these findings derive from observational cohort studies, the GRADE certainty is rated as low.

0:09:21Shanna Swansupportedhigh

Phthalates are water-soluble compounds whose metabolites are excreted and measurable in human urine.

"And they're measurable in the human body pretty easily, which makes my work much easier, because they're water-soluble. And being water-soluble, they get into the urine as metabolites. They're metabolized, and so we measure metabolites of phthalates in the urine fairly easily." (said at 0:09:21)

The speaker's claim is supported by pharmacokinetic and biomonitoring literature. Diesters of phthalic acid undergo Phase I and Phase II biotransformation in the body to form monoesters and glucuronide conjugates. Phase II conjugation (e.g., glucuronidation) increases the water solubility of these compounds, facilitating their rapid excretion in human urine where their primary and secondary metabolites are easily measured as biomarkers of exposure (PMID: 14574443, PMID: 34520948, PMID: 35131323).

0:18:59Shanna Swansupportedmoderate

PFAS chemicals interfere with human antibody responses to vaccinations.

"they're conveying harm because they interfere with your antibody response to vaccines, for example." (said at 0:18:59)

Prospective human cohort studies and booster vaccination trials show that exposure to per- and polyfluoroalkyl substances (PFAS) is inversely associated with antibody responses to vaccines, including tetanus, diphtheria, and hepatitis vaccines. Higher serum concentrations of PFAS during early childhood, adolescence, and adulthood correlate with significant reductions in post-vaccination specific serum antibody titers.

0:22:00Mark Hyman (host)supportedmoderate

A New England Journal of Medicine study found that microplastics present in arterial plaques are linked to an increased risk of cardiovascular events.

"there was a seminal paper that came out in the New England Journal of Medicine which talked about microplastics in the atheromas or the plaques in arteries and how that was linked to increased risk of cardiovascular events." (said at 0:22:00)

A prospective, multicenter study published in the New England Journal of Medicine (Marfella et al., 2024) evaluated 257 patients undergoing carotid endarterectomy for asymptomatic carotid artery disease. Microplastics and nanoplastics (specifically polyethylene and polyvinyl chloride) were detected in the excised carotid artery plaques of 58.4% of patients. Over a mean follow-up of 34 months, patients with detectable plastics in their atheromas had a significantly higher risk of a composite cardiovascular end point (myocardial infarction, stroke, or all-cause mortality) compared to those without detectable plastics (hazard ratio, 4.53; 95% CI, 2.00 to 10.27; P<0.001).

0:24:07Shanna Swansupportedmoderate

Microplastics have been detected and measured in human blood, placentas, seminal fluid, and breast milk.

"People have measured them in their blood. They've been measured in placentas. They've been measured in seminal fluid. They've been measured in breast milk." (said at 0:24:07)

Multiple human biomonitoring studies and systematic reviews confirm that microplastics have been detected and quantified across various human biological fluids and tissues, specifically including whole blood, placental tissue, semen/seminal fluid, and breast milk.

0:16:54Shanna Swansupportedmoderate

Phthalates act as anti-androgenic chemicals that lower androgen/testosterone levels.

"Phthalates are a class of several chemicals which have a similar structure and similar effect. And by the way, the phthalates are androgen-lowering. They're anti-androgens, okay?" (said at 0:16:54)

Phthalates are well-established environmental endocrine disruptors that exert anti-androgenic effects. Mechanistic and animal studies demonstrate that phthalate exposure impairs testosterone biosynthesis in Leydig cells by suppressing the expression of key steroidogenic enzymes. Systematic reviews of human epidemiological evidence also show associations between exposure to major phthalates (such as DEHP, DBP, and DINP) and reduced testosterone levels as well as other anti-androgenic reproductive outcomes.

0:11:00Shanna Swansupportedmoderate

Phthalates are added to cosmetics and pesticides to increase barrier absorption and are used in fragranced products to retain scent and color.

"it helps the absorption through a skin barrier or other barriers of chemicals. And so, it's added to hand lotion, and it's also added to pesticides... And another important thing it does: it helps retain scent and color. So, it's added to makeup—lipstick and products you put on your skin—as well as fragrance." (said at 0:11:00)

Phthalates (most notably diethyl phthalate [DEP] and dibutyl phthalate [DBP]) are widely documented functional additives in cosmetics, fragranced personal care items, and agrochemical formulations. In cosmetic and fragrance formulations, low-molecular-weight phthalates function as solvents and fragrance fixatives that retard evaporation to prolong scent retention, as well as plasticizers and permeation aids in leave-on products such as lotions, nail polishes, and creams.

0:12:00Shanna Swansupportedhigh

The Consumer Product Safety Improvement Act of 2008 banned phthalates from children's toys in the United States.

"Finally, they decided that they would ban it in children's toys—that's the rubber ducky... The Consumer Product Safety Improvement Act of 2008 did not protect pregnant women." (said at 0:12:00)

Section 108 of the Consumer Product Safety Improvement Act (CPSIA) of 2008 enacted federal restrictions banning specific phthalates in concentrations greater than 0.1% from children's toys and child care articles in the United States. The law was specifically written to cover products intended for children rather than adult consumer goods or interventions tailored to pregnant women.

0:37:59Shanna Swansupportedmoderate

Human spermatogenesis takes approximately 70 days.

"And why three months? Well, it's because it takes 70 days to make a sperm." (said at 0:37:59)

Human spermatogenesis is classically estimated to take approximately 64 to 74 days. In classic kinetic studies using intratesticular injections of tritiated thymidine, the duration of testicular spermatogenesis alone was calculated to take approximately 64 days across roughly four cycles of the seminiferous epithelium. When factoring in the additional 10 to 14 days required for transit through the epididymis to produce mature spermatozoa in the ejaculate, the total timeline from spermatogonial differentiation to ejaculation is widely recognized in physiology as taking approximately 70 to 74 days (roughly 2.5 to 3 months).

0:42:20Shanna Swansupportedmoderate

Touching thermal paper receipts, particularly when wearing hand cream, causes significant absorption of bisphenols into the body.

"Because you when you touch that—we've done a study which shows you touch that, particularly if you have hand cream on, you're getting a lot of bisphenols into your body, and every cashier gets a lot." (said at 0:42:20)

Published experimental and occupational exposure studies confirm that handling thermal paper receipts transfers substantial amounts of free bisphenols (such as bisphenol A / BPA) onto the skin. The presence of dermal penetration enhancers, hand creams, lotions, or sanitizers markedly increases both the transfer to skin and systemic absorption into blood and urine, bypasses first-pass hepatic metabolism, and leads to heightened exposure among cashiers who repeatedly handle receipt paper.

  • supports: Transfer of bisphenol A from thermal printer paper to the skin. (Analytical and bioanalytical chemistry 2010) · cited 430x in the literature
    "When taking hold of a receipt consisting of thermal printing paper for 5 s, roughly 1 microg BPA (0.2-6 microg) was transferred to the forefinger and the middle finger if the skin was rather dry and about ten times more if these fingers were wet or very greasy." (abstract, results, passage verified)
    pubmedfull study (doi)
  • supports: Holding thermal receipt paper and eating food after using hand sanitizer results in high s… (PloS one 2014) · cited 203x in the literature
    "Not taken into account when considering thermal paper as a source of BPA exposure is that some commonly used hand sanitizers, as well as other skin care products, contain mixtures of dermal penetration enhancing chemicals that can increase by up to 100 fold the dermal absorption of lipophilic compounds such as BPA. We found that when men and women held thermal receipt paper immediately after using a hand sanitizer with penetration enhancing chemicals, significant free BPA was transferred to their hands and then to French fries that were eaten, and the combination of dermal and oral BPA absorption led to a rapid and dramatic average maximum increase (Cmax) in unconjugated (bioactive) BPA of ∼7 ng/mL in serum and ∼20 µg total BPA/g creatinine in urine within 90 min." (abstract, results, passage verified)
    pubmedfull study (doi)
0:43:26Shanna Swansupportedmoderate

Metal food cans are lined with bisphenol unless explicitly specified otherwise by the manufacturer.

"It lines all your tin cans unless there's a specific effort by the company to say they are not using bisphenol in their linings" (said at 0:43:26)

Bisphenol A (BPA)-based epoxy resins have traditionally served as the standard protective coating lining metal food and beverage cans. Literature on food packaging and regulatory transitions confirms that non-bisphenol alternatives (referred to as BPA-free or BPA-Non-Intent / BPA-NI chemistries) require deliberate reformulation and specific industry compliance effort to replace standard BPA-based epoxy linings.

0:45:09Shanna Swansupportedhigh

Thalidomide taken during pregnancy caused children to be born with limb reduction defects.

"One of them was thalidomide that caused children to be born without arms and legs" (said at 0:45:09)

Thalidomide exposure during early pregnancy is well documented as a potent teratogen that causes severe limb reduction defects, notably phocomelia (severe shortening or absence of long bones) and amelia (complete absence of limbs), alongside other congenital abnormalities.

0:45:09Shanna Swansupportedhigh

Diethylstilbestrol (DES) taken during pregnancy caused cancer in children born to those women.

"and one was DES, diethylstilbestrol, which caused cancer in the children born to women who took it during pregnancy." (said at 0:45:09)

The statement is supported by decades of epidemiological and clinical research. Diethylstilbestrol (DES) was prescribed to pregnant women primarily between 1938 and 1971. In utero exposure was definitively shown to cause rare vaginal and cervical clear cell adenocarcinoma (CCA) in female offspring, along with other reproductive tract abnormalities and an elevated risk of subsequent breast cancer.

0:46:46Shanna Swansupportedhigh

Under the European Union's REACH regulation, a new chemical product cannot be placed in commerce until it is tested for safety.

"REACH is a program that was um put in place by the EU... And it has the really important um caveat, which is um if you want to bring in a new product and put it in commerce, you can't do that until it's tested for safety first." (said at 0:46:46)

Under the European Union's REACH regulation (Regulation (EC) No 1907/2006 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals), manufacturers and importers are required to demonstrate the safety of chemical substances by submitting hazard and safety dossiers prior to placing them on the EU market. This foundational rule is known in EU law and policy analysis as the 'no data, no market' principle, which places the burden of proof on industry to identify intrinsic chemical properties and safe handling conditions before commercial distribution.

0:46:57Shanna Swansupportedhigh

Microwaving food in plastic containers causes plasticizers to migrate out of the plastic matrix and into the food.

"Because what happens is that the plasticizers which are added to the plastic are not tightly bound to that matrix, and so when you heat it, the particles get active, they hop out of the plastic, they hop into your food, they get into your body." (said at 0:46:57)

The claim is supported. Plasticizers (such as phthalate esters) are added to polymers as non-covalently bound additives to increase flexibility and workability. Because they are not chemically bound to the polymer matrix, heating (including microwave heating) increases molecular mobility and accelerates the migration (leaching) of plasticizers from plastic food contact materials into food or food simulants, leading to dietary exposure.

0:49:33Shanna Swansupportedmoderate

Pregnant women who report using fragranced products have higher measured bodily levels of phthalates.

"We asked them what they used in the last 24 hours, and then we asked, was it fragranced? And when the women reported use of fragranced products, their levels of several chemicals were higher, particularly the phthalates in their bodies." (said at 0:49:33)

Observational cohort studies in pregnant and postpartum women consistently demonstrate that self-reported use of personal care products (such as perfumes and fragranced products) within the previous 24 to 48 hours is associated with higher urinary concentrations of phthalate metabolites, most notably monoethyl phthalate (MEP).

1:02:37Shanna Swansupportedhigh

Products marketed as BPA-free often substitute BPA with other bisphenol analogs such as BPF and BPS.

"Probably if they took the trouble to put BPA-free on the label, they've already put in an alternative like BPF and BPS." (said at 1:02:37)

Extensive literature and systematic reviews confirm that when bisphenol A (BPA) was phased out of consumer plastics, resins, and thermal paper due to health regulations and consumer pressure, manufacturers widely substituted BPA with structural analogs—predominantly bisphenol S (BPS) and bisphenol F (BPF)—while labeling products as 'BPA-free'.

1:03:08Shanna Swansupportedhigh

Only a very small percentage of plastic waste placed in recycling bins is actually recycled.

"Well, we all put our plastic in the recycle box back then, right? Me too. But a very small percent of that is actually recycled" (said at 1:03:08)

Global assessments of plastic life cycles and waste management consistently indicate that only a small fraction of plastic waste is successfully recycled. Cumulative global estimates and waste tracking studies show that less than 10% to 16% of all plastic waste generated is recycled, with the overwhelming majority ending up in landfills, incinerated, or discarded into the environment. Furthermore, studies tracking materials placed into municipal recycling streams have documented significant losses due to sorting limitations, lack of viable end-markets, contamination, and the inadequate handling of exported plastic waste.

1:04:09Shanna Swansupportedhigh

Heating food or liquids in plastic results in greater chemical exposure than merely storing them in plastic.

"Oh, heating in plastic, no question. Heating." (said at 1:04:09)

Extensive physical chemistry and food safety literature confirms that heating food or liquids in plastic significantly increases chemical migration and leaching compared to low-temperature or room-temperature storage. Systematic reviews and standardized experimental migration assays show that elevated temperatures (such as during microwaving, boiling, or hot filling) accelerate the diffusion kinetics of plasticizers (e.g., phthalates), monomers (e.g., bisphenols), synthetic phenolic antioxidants, and non-intentionally added substances into food and food simulants.

1:05:11Shanna Swansupportedmoderate

PFAS chemicals are added to stain- and water-resistant fabrics and clothing, including flight attendant uniforms, firefighter gear, sportswear, and children's school uniforms.

"And it's particularly concerning if you use clothing that has barriers, like flight attendants, firefighters, sportswear, children's school uniforms. PFAS was the class of chemical I'm talking about that's added to all of these" (said at 1:05:11)

Published analytical chemistry and environmental exposure studies confirm that per- and polyfluoroalkyl substances (PFAS) are applied to textiles and apparel requiring durable water, oil, or stain resistance. This includes firefighter turnout gear (where PFAS are used in moisture barriers and outer shells), outdoor apparel and sportswear, and stain-resistant children's school uniforms.

1:07:14Mark Hyman (host)supportedmoderate

The European Union regulates chemicals using the precautionary principle, whereas the United States allows chemicals onto the market without requiring manufacturers to first prove safety.

"In Europe, they follow something called the precautionary principle, which is something's guilty until proven innocent. In America, it's innocent until proven guilty. So we introduce all these toxic chemicals. We don't make the manufacturers prove they're safe." (said at 1:07:14)

The claim accurately reflects the core conceptual difference between European Union and United States chemical regulations. The EU's primary framework, REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals), explicitly incorporates the precautionary principle and the 'no data, no market' rule, placing the primary burden of proof on manufacturers and importers to demonstrate safe use. In contrast, under the original US Toxic Substances Control Act (TSCA) of 1976, the Environmental Protection Agency (EPA) bore the burden of proving an 'unreasonable risk' before it could mandate testing or restrict a substance, allowing tens of thousands of chemicals into commerce without comprehensive upfront safety data. While the US revised TSCA in 2016 through the Frank R. Lautenberg Chemical Safety for the 21st Century Act to require affirmative EPA safety findings for new chemicals, the fundamental transatlantic distinction between the EU's precautionary framework and the US risk-management approach remains recognized in regulatory policy.

Unverified means no publication matching the claim was located; it does not prove the claim false. Spotted an error? See the corrections policy - disputes from the people quoted are prioritized.