We Were Wrong About Sulforaphane and Astaxanthin?

Summary

The video reassesses claims that sulforaphane and astaxanthin activate the body’s NRF2 pathway and provide major health benefits. The presenter concludes that the evidence is more modest and uncertain than some supplement claims suggest. Eating a varied diet rich in vegetables—and getting astaxanthin from foods such as salmon—is presented as more worthwhile than buying either supplement.

Sulforaphane: Promising Biology, Mixed Human Evidence

• What it is and how it forms: Broccoli and other cruciferous vegetables contain glucoraphanin, a stable precursor. When the plant is crushed or chewed, the enzyme myrosinase can convert it into sulforaphane. Heat destroys myrosinase, so cooking can substantially reduce sulforaphane formation.
• Why it attracted interest: Animal studies found fewer tumors after sulforaphane exposure. Later research linked some of its protective effects to NRF2, a pathway involved in regulating many genes, including those related to the body’s defenses and detoxification.
• Getting it into the body matters: In one comparison described in the video, raw chopped broccoli led to much more sulforaphane entering the blood and urine than cooked broccoli.
• A caution about NRF2 drugs: A large trial of the NRF2-activating drug bardoxolone methyl in people with type 2 diabetes and progressive kidney disease was stopped early. The drug did not protect kidney function and was associated with more heart failure, particularly among people already at risk. The presenter notes that this was a drug trial, not a test of broccoli sprouts or sulforaphane.
• Human detox findings: In a 12-week study in a heavily polluted region of China, people who drank a broccoli-sprout beverage excreted more benzene breakdown products in their urine than those given a placebo. This suggests an effect on one detoxification-related outcome, but does not establish broader health benefits.
• The prostate-cancer-marker claim needs context: A small trial in 87 men with rising PSA after prostate surgery reported an 86% slower rate of PSA doubling with stabilized sulforaphane. However, the main result did not reach statistical significance, so it is suggestive rather than conclusive.
• Diet associations do not prove sulforaphane is responsible: One large observational study linked higher cruciferous-vegetable consumption with lower mortality. But people who eat more of these vegetables may differ in many other ways, so the association cannot establish that sulforaphane caused the difference.
• Blood-sugar results have weakened: An early 2017 study reported lower fasting blood sugar and HbA1c in people with type 2 diabetes. Later studies produced less encouraging results:
  • A 2025 trial found a statistically significant but small reduction in blood sugar that fell short of the researchers’ target; HbA1c did not change.
  • A 2026 trial found no difference in fasting blood sugar, insulin, or HbA1c, despite sulforaphane being detected in participants’ blood.

Overall assessment: The presenter says that human evidence for NRF2 activation by sulforaphane is limited, and the apparent blood-sugar benefit now looks small or absent. Individual responses may vary, possibly in part because gut bacteria differ.

Astaxanthin: Limited Skin Evidence and Inconsistent Mouse-Lifespan Results

• What it is: Astaxanthin is a red pigment found in foods such as salmon. Unlike sulforaphane, it is relatively stable and has been measured in people’s blood after supplementation. The presenter says evidence for its effects on NRF2 in humans is limited.
• Skin studies: Trials have reported possible improvements in skin moisture or elasticity, but the evidence is weak:
  • A 2017 study in 65 women found no significant differences between the astaxanthin and placebo groups on the measured outcomes when compared directly.
  • A 2018 sunburn-related study involved only 22 people and was funded by a supplement company. One measure favored astaxanthin, but the groups ultimately needed about the same UV exposure before their skin reddened.
  • A 2021 review of studies involving about 300 people found signals for improved moisture and elasticity, but not a significant reduction in wrinkles. The authors described the findings as preliminary and noted industry involvement in several studies.
  • A 2025 review of supplements for sun-damaged skin found insufficient evidence to recommend astaxanthin.
• Mouse lifespan studies: In a National Institute on Aging testing program, astaxanthin added to the diets of middle-aged mice was reported in 2023 to extend male mice’s lives by about 12% across three laboratories; female mice did not benefit. A 2026 follow-up tested a lower dose rather than repeating the exact same conditions and found no lifespan benefit. Possible explanations include a dose- or age-specific effect, or that the original finding was a chance result.

Overall assessment: The presenter considers the human skin benefits too minor or uncertain to justify buying astaxanthin for that purpose. The mouse results are interesting but do not establish a benefit in people.

Practical Takeaways

• Eat a variety of vegetables, including cruciferous vegetables. The video favors getting sulforaphane-related compounds through food rather than supplements.
• Include astaxanthin-containing foods, such as salmon, if they fit your diet.
• Treat supplement claims cautiously, especially when evidence comes from small trials, results are not significant between groups, or studies are funded by supplement companies.
• The presenter also cautions that high antioxidant intake may interfere with exercise adaptations in some circumstances, while noting that antioxidants can sometimes help training outcomes when used appropriately.

Speakers and Sources Featured

• Dr. Brad Stanfield — The video’s presenter and narrator, who evaluates the research and gives the practical conclusions. He also includes promotional messages for his health roadmap and potassium-and-fiber drink.
• Dr. Rhonda Patrick — Quoted through past talks and a 2016 video as an advocate for sulforaphane and cruciferous vegetables.
• Researchers and study teams referenced — These include researchers at Johns Hopkins University, the Lund University team, authors of human-trial reviews, and the U.S. National Institute on Aging’s mouse-testing program. No individual researchers are identified by name in the subtitles.