Ergothioneine: The Mushroom 'Longevity Vitamin' Your Body Can't Make on Its Own

The Oasis Health Journal · Submitted July 4, 2026 · 2:15 PM ET

A mushroom just got a promotion. For 16 weeks, 147 adults between the ages of 55 and 79 took either a placebo or a small daily dose of ergothioneine, an antioxidant the human body cannot make on its own and can only get from food, mostly mushrooms. The 2025 results, published in the journal Nutraceuticals, found the group on 25 mg a day slept better, reported sharper day-to-day memory, and showed improved liver markers. Nobody grew gills. Still a solid showing for a compound most people have never heard of.

Ergothioneine has been quietly on the clock since 1909, when chemists first isolated it from ergot fungus and named it accordingly. It took about a century for anyone to notice it might matter. In 2005, researchers found something odd: the human body has a dedicated transporter protein, OCTN1, whose entire job seems to be hunting down ergothioneine and stuffing it into the tissues that take the most oxidative abuse, including the liver, the eyes, the brain, and bone marrow. Evolution does not build a specialized delivery service for a nutrient it does not care about. Nobody has a transporter this committed to, say, potato chips.

That kind of biological main-character energy is why Bruce Ames, the UC Berkeley biochemist who spent decades studying aging, proposed calling ergothioneine a 'longevity vitamin' in a 2018 paper in the Proceedings of the National Academy of Sciences. His argument: nutrients the body clearly prioritizes for long-term upkeep, yet that are not officially classified as essential, might be exactly what quietly runs short as we age. Blood ergothioneine levels do decline with age, and lower levels have been linked to faster cognitive and functional decline in older adults seen at memory clinics. Correlation, not proof, but a consistent enough pattern that a 2025 review in Proceedings of the Nutrition Society called for larger trials to settle whether raising ergothioneine levels actually slows any of this down, rather than just riding along with it.

That same review connects ergothioneine to a longer list of body systems than a compound this size has any right to be involved in: cardiovascular, metabolic, gut, eye, hearing, liver, kidney, immune, skin, even lung health show up in early research. That does not mean one mushroom molecule is secretly running your entire body. It means researchers are still mapping how far a single well-placed antioxidant can reach, and the map keeps growing.

Back to the 16-week trial. Participants took 10 mg or 25 mg of ergothioneine a day, and plasma levels rose accordingly, up to sixteen-fold in the higher-dose group by the end, so the capsules were clearly not decorative. The 25 mg group reported improved sleep initiation and better day-to-day memory, both statistically significant. A lab measure of overall memory improved at the four-week mark but did not hold at sixteen weeks, the kind of detail a press release would leave out and a journal would not. Reaction time improved in both dose groups over time. Liver function markers moved in a favorable direction, and researchers noted a small rise in telomere length in the lower-dose group, particularly among women, an early signal that needs its own dedicated trial before it belongs on a label as a promise.

None of this makes ergothioneine a cure for anything, and nobody studying it claims otherwise. It is sold in the U.S. as a dietary supplement, not a drug, and the research so far is best described as promising, early, and worth watching rather than settled. The average American plate is not exactly overflowing with mushrooms, which is part of why researchers keep pointing at the gap between what we eat and what our OCTN1 transporters are clearly hoping for.

If you already reach for mushroom-based supplements for the immune and cognitive support their compounds are known for, this research is one more reason to keep the habit going. Pair it with an antioxidant formula for general oxidative stress support, a brain health blend if memory and focus are the goal, or a sleep support option if the trial's sleep finding is the part that caught your eye. As always: sourced fresh per order, not pulled off a warehouse shelf that has seen better days. The wait is the price of potency that has not been sitting around losing it.

This article is for educational purposes only and is not medical advice. Talk to a healthcare provider before starting any new supplement.

Sources

1. Zajac et al., Effect of Ergothioneine Supplementation on Cognitive Function, Memory, and Sleep in Older Adults with Subjective Memory Complaints: A Randomized Placebo-Controlled Trial, Nutraceuticals (2025)
2. May-Zhang et al., Ergothioneine for Cognitive Health, Longevity and Healthy Ageing: Where Are We Now?, Proceedings of the Nutrition Society (2025)
3. Ames, Prolonging Healthy Aging: Longevity Vitamins and Proteins, PNAS (2018)
4. Cheah et al., Ergothioneine Levels in an Elderly Population Decrease with Age and Incidence of Cognitive Decline, Biochemical and Biophysical Research Communications (2016)
5. Wu et al., Low Plasma Ergothioneine Predicts Cognitive and Functional Decline in an Elderly Cohort Attending Memory Clinics, Antioxidants (2022)
6. Beelman et al., Is Ergothioneine a Longevity Vitamin Limited in the American Diet?, Journal of Nutritional Science (2020)