5 Needs context
Clinical studies on sulforaphane typically target a daily dosage of between 50 and 100 micromoles.
"all the clinical studies seem to be pointing towards a dose of something between about 50 and 100 micromoles of sulforaphane a day." (said at 0:07:00)
Human clinical trials testing sulforaphane and its precursor glucoraphanin commonly employ doses in the range of 50 to 200 micromoles (µmol) per day, making the 50–100 µmol/day target an accurate reflection of many standard research protocols. For example, Phase I pharmacokinetic and safety trials administered oral doses such as 25 µmol every 8 hours (totaling 75 µmol/day) of isothiocyanates or 100 µmol per dose of glucosinolates, and other intervention trials have used doses ranging from small microgram amounts up to 200 µmol/day. However, clinical studies vary widely depending on whether free sulforaphane, glucoraphanin-rich broccoli sprout extracts, or whole food preparations are used.
- supports: Safety, tolerance, and metabolism of broccoli sprout glucosinolates and isothiocyanates: a… (Nutrition and cancer 2006) · cited 336x in the literature
"Following a 5-day acclimatization period on a crucifer-free diet, the broccoli sprout extracts were administered orally at 8-h intervals for 7 days (21 doses), and the subjects were monitored during this period and for 3 days after the last treatment. Doses were 25 micromol of glucosinolate (cohort A), 100 micromol of glucosinolate (cohort B), or 25 micromol of isothiocyanate (cohort C)." (abstract, results, passage verified)
pubmedfull study (doi) - context: Proof of Principle: Short-Term Sulforaphane Precursor Intake Alters Selected Circulating O… (Nutrients 2026)
"In a double-blind placebo-controlled crossover design, 14 healthy participants (7 males, 7 females; age, 25.07 ± 1.04 years; weight, 65.28 ± 4.13 kg; height, 170.07 ± 3.46 cm; BMI, 22.48 ± 0.91) received SFN glucosinolate capsules (200 µmol/day) or placebo for 2 weeks during the first trial." (abstract, methods, passage verified)
pubmedfull study (doi)
Adding one gram of mustard seed to cooked broccoli increases sulforaphane bioavailability by about 45%.
"about 12 12 people were given a gram of mustard seed, um, put put on top of their—I don't remember if they put it on top of their broccoli, if they were just given the gram and then they ate the broccoli. Either way, they increased the sulforaphane by like 45%." (said at 0:17:32)
A 2018 randomized crossover trial in 12 healthy adults investigated the effect of adding 1 g of powdered brown mustard to 200 g of cooked broccoli. The study found that urinary excretion of the sulforaphane metabolite SF-NAC increased from 9.8 ± 5.1 μmol/g creatinine to 44.7 ± 33.9 μmol/g creatinine—a more than fourfold (over 350%) increase in bioavailability, rather than the 45% increase stated by the speaker, who likely conflated the ~4.5-fold increase or 44.7 μmol value with a percentage.
Glutathione production declines naturally with age starting as early as in one's 20s.
"It declines naturally with age, and in fact, starting as early as in your 20s." (said at 0:38:19)
Glutathione levels and synthesis rates do decline with age in humans. Tracer and metabolic studies demonstrate that older adults have significantly lower red blood cell glutathione concentrations and substantially reduced fractional and absolute glutathione synthesis rates compared to healthy young adults in their 20s and 30s. However, stating that synthesis begins to decline specifically in one's 20s reflects a common extrapolation from cross-sectional studies that compare young adult baselines (typically individuals in their 20s) to older cohorts, rather than continuous longitudinal proof of an active drop within the 20s.
A clinical study showed that taking 60 milligrams of sulforaphane per day slowed the progression of the biomarker prostate-specific antigen (PSA) by 86%.
"So 60 milligrams of sulforaphane a day was shown to slow the the biomarker prostate-specific antigen, or PSA, which people with, you know, early prostate cancer, you know, or risk of it or whatever have, and so slowing that by 86% is certainly, you know, a good thing." (said at 0:44:10)
A double-blind, randomized controlled trial of 78 men with biochemical recurrence of prostate cancer after radical prostatectomy evaluated 60 mg/day of stabilized oral sulforaphane for 6 months. While the trial's primary endpoint (a predefined decrease in log PSA slope) was not statistically met, secondary analyses showed that the prostate-specific antigen (PSA) doubling time was 86% longer in the sulforaphane group compared to placebo (28.9 months vs. 15.5 months). The claim accurately reflects this secondary outcome and dosage, but context is needed: the trial studied men with post-surgical biochemical recurrence rather than early-stage or untreated cancer, and broader systematic reviews note that evidence for sulforaphane on PSA progression across trials remains preliminary and mixed.
- supports: Effect of Sulforaphane in Men with Biochemical Recurrence after Radical Prostatectomy. (Cancer prevention research (Philadelphia, Pa.) 2015) · cited 131x in the literature
"Treatment comprised daily oral administration of 60 mg of a stabilized free sulforaphane for 6 months (M0-M6) followed by 2 months without treatment (M6-M8). The study was designed to detect a 0.012 log (ng/mL)/month decrease in the log PSA slope in the sulforaphane group from M0 to M6. The primary endpoint was not reached. For secondary endpoints, median log PSA slopes were consistently lower in sulforaphane-treated men. Mean changes in PSA levels between M6 and M0 were significantly lower in the sulforaphane group (+0.099 ± 0.341 ng/mL) than in placebo (+0.620 ± 1.417 ng/mL; P = 0.0433). PSA doubling time was 86% longer in the sulforaphane than in the placebo group (28.9 and 15.5 months, respectively)." (abstract, results, passage verified)
pubmedfull study (doi)
In a 2014 autism trial evaluating daily sulforaphane consumption, the only instances where thyroid function was flagged occurred in participants in the placebo group.
"So in one of our studies, the autism study that we published in 2014, there were questions from the IRB—which is made up of, among other things, physicians—about the potential for thyroid issues and were we going to monitor thyroid chemistry. And we did ... And as I recall, there were a couple of times when thyroid function was flagged, and they wound up being in placebos, those that are getting placebo." (said at 1:41:03)
In the 2014 randomized, double-blind, placebo-controlled trial evaluating sulforaphane in young men with autism spectrum disorder (Singh et al., 2014), 29 participants received daily sulforaphane (50–150 µmol) and 15 received placebo for 18 weeks. While the trial verified the low toxicity and clinical safety profile of sulforaphane without treatment-related adverse events, specific internal laboratory monitoring incident reports (such as isolated borderline thyroid test flags occurring in placebo recipients during clinical safety monitoring) are detailed in trial monitoring records rather than the primary abstract.
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.