Supplement: Ergothioneine

What It Is

Ergothioneine is a sulfur-containing amino acid, and every molecule comes from the diet. Fungi and certain soil bacteria build it, and plants and animals take it up from there and pass it along the food chain.

The biochemist Bruce Ames proposed the name "longevity vitamin" in 2018 for a small group of diet-derived compounds not strictly essential for survival but possibly important for a long, healthy life.

What It Does

Three separate groups of people have been followed over time. Those who started with more ergothioneine in the blood went on to die at lower rates, to develop fewer heart problems, and to lose cognitive function more slowly. Among older adults, a low reading predicted faster decline in thinking and memory.

The Research & Studies

Everything here is based on the research we have collected and checked, sorted into groups and ordered with the strongest evidence first. Click any claim to open the studies behind it.

How it works

The body has a dedicated transporter (OCTN1 / SLC22A4) that actively concentrates ergothioneine in tissuesModerate · mixed

In plain terms

Humans have a specific, gene-encoded pump that grabs ergothioneine from food and stores it in tissues, which is why researchers suspect the body needs it for something.

In detail

Ergothioneine is taken up by a specific transporter, OCTN1, encoded by the gene SLC22A4, shown in 2005 to carry ergothioneine with high affinity. The body absorbs it avidly, excretes little (under 4 percent of an oral dose in the urine), and concentrates it in tissues under oxidative stress such as red blood cells, the liver and the lens of the eye. A dedicated transporter is the main argument that ergothioneine plays a physiological role, not passing through as an inert food component. A dedicated transporter shows the body handles ergothioneine deliberately; on its own it does not prove a health benefit or that supplementing helps.

The study · 1

Grundemann et al., Discovery of the ergothioneine transporter · Proc Natl Acad Sci USA 2005;102(14):5256-5261

Longevity And Mortality

Higher blood ergothioneine tracked with about 14% lower all-cause and 21% lower cardiovascular death per 1 SDPreliminary

In plain terms

Swedish adults with more ergothioneine in their blood were less likely to die, or to develop or die from heart disease, over the next roughly 20 years, about 14 to 21% lower risk for each step up in level.

In detail

In 3,236 Swedish adults free of cardiovascular disease and diabetes at baseline, each 1 standard-deviation higher plasma ergothioneine was associated with a 14% lower risk of death from any cause (hazard ratio 0.86), 21% lower cardiovascular mortality (0.79) and 15% lower risk of coronary disease (0.85), over a median 21.4 years, after adjustment for age, sex, body-mass index, blood lipids, blood pressure, smoking and alcohol. Measured in: 3,236 adults (61% women), mean age 57, from the population-based Malmo Diet and Cancer study, Sweden. What could explain it instead: Ergothioneine was the metabolite most tightly linked to a health-conscious food pattern (fish, vegetables, whole grains), so a higher level may mark a better overall diet and the healthier life around it, not an effect of the compound. Reverse causation is also possible: early or hidden illness can lower the level, making a low reading look more harmful than it is.. One observational cohort measuring the level already in the blood; nobody was given ergothioneine, so this cannot show the compound caused the lower death rate.

The study · 1

Smith et al., Ergothioneine is associated with reduced mortality and decreased risk of cardiovascular disease · Heart 2020;106(9):691-697

Cognition

Lower plasma ergothioneine predicted faster cognitive and functional decline in older adultsPreliminary

In plain terms

Older adults with less ergothioneine in their blood tended to think and function worse at the start and to slip faster over the following years, across memory and several other mental skills.

In detail

Among 470 older adults attending memory clinics in Singapore, lower plasma ergothioneine at baseline predicted poorer cognition to start and faster decline over follow-up across memory, executive function, attention, processing speed and language, as well as faster functional decline. The longitudinal link held in people who were not yet demented. Measured in: 470 older adults attending memory clinics, Singapore. What could explain it instead: Being unwell lowers ergothioneine, so a low level in a declining person may be a consequence of failing health, not a cause of it (reverse causation). Diet quality and general health also differ between people with high and low levels.. An observational cohort of people already attending memory clinics; it measured the level, it did not supplement anyone, so it cannot show that raising ergothioneine would slow decline.

The study · 1

Wu et al., Low Plasma Ergothioneine Predicts Cognitive and Functional Decline in an Elderly Cohort Attending Memory Clinics · Antioxidants (Basel) 2022;11(9):1717

A Marker, Not Yet a Medicine

Every one of those findings measured ergothioneine already in the blood; none gave the compound to anyone. The level rises with a diet rich in mushrooms, fish, vegetables and whole grains, the same health-conscious eating pattern that tracks with lower disease on its own. In the largest study, ergothioneine was the single metabolite most tightly linked to that pattern. So the diet may account for part of the tie between a high level and a longer life. Illness can also lower the level.

A low reading can therefore be a result of poor health as well as a possible driver of it.

The strongest argument that ergothioneine has a real role is biological. The body evolved a specific transporter just for ergothioneine, and a molecule with its own transporter usually has a function. That is a reason to keep studying it. It does not show that a capsule extends anyone's life.

What would settle the question is a randomized trial: some people given ergothioneine, others a placebo, real outcomes followed over years. None has been run for lifespan, heart disease or dementia. When purified ergothioneine was given to healthy adults, it did not clearly change markers of oxidative damage or inflammation. One early study finding nothing may simply mean a healthy body has little to fix.

How It Works

Ergothioneine enters through a carrier protein, works as an antioxidant in the lab, and gathers in the tissues under most oxidative strain.

Anatomy of the Practice

1A dedicated transporter pulls it from food (shown in humans)

Ergothioneine is absorbed and retained by a specific transporter, OCTN1, encoded by the gene SLC22A4, identified in 2005 as its carrier. The body absorbs it avidly and excretes very little: under 4 percent of an oral dose in the urine. It then concentrates the rest in tissues under oxidative stress: red blood cells, the liver and the lens of the eye. This handling is well established in people.

2It behaves as an antioxidant and cytoprotectant (mostly cells and animals)

In the laboratory ergothioneine scavenges reactive oxygen species, binds metal ions that would otherwise drive oxidation, and protects cells under stress. This chemistry is well characterized in cells and animal models. Whether it translates into a measurable health effect in a living person is the step that has not been demonstrated.

3It accumulates where the body is under strain (mixed evidence)

The transporter switches on in tissues under inflammation and oxidative stress, so ergothioneine builds up right where that strain is greatest. The build-up is documented. Whether more of it actually protects those tissues over a lifetime is the open question the population studies raise.

Do It Yourself

Mushroom content spans a wide range, from about 0.15 to 7.3 milligrams per gram of dry weight depending on the species.

Ways to Do It

The rungs run from everyday food to a purified supplement, with a plain note on what is and is not known about the last one.

1

Eat a variety of mushrooms regularlyFreeEasy

Mushrooms are the highest dietary source by a wide margin. Specialty types (oyster, shiitake, king oyster and porcini) carry the most, and common white button, cremini and portobello carry less but still contribute across a week. A mix of common and specialty types covers the range. This is the route behind essentially all of the evidence that ergothioneine tracks with better health, because that evidence comes from people who ate mushrooms.

2

Cook them, and eat the whole mushroomFreeEasy

Ergothioneine is heat-stable, so cooking keeps most of it, and cooking also makes mushrooms easier to digest and safer than raw. There is no special preparation to preserve it: saute, roast, or add them to soups and stews as usual.

3

Organ meats and beans as minor sources$Easy

Liver, kidney, black and red beans, and oat bran add small amounts, useful if they are already part of how you eat. Mushrooms have several times more, so keep them as the main source.

4

A purified L-ergothioneine supplement$$Easy

Purified L-ergothioneine is sold as a capsule, usually in low milligram doses. You are buying a nutrient with a promising marker profile and no proven benefit. No trial has shown that taking it lengthens life, protects the heart or slows cognitive decline. It is well tolerated at these doses and well absorbed. A capsule can sit on top of a good diet as an experiment for someone who wants it.

Go Deeper

• Medicinal mushrooms: the wider tradition and evidence for mushrooms as food and medicine, where ergothioneine is one thread among many.
• Mediterranean diet: the whole-food eating pattern that carries ergothioneine along with everything else linked to a longer life.
• Dementia: where the cognitive findings fit, and what has and has not been shown to protect the aging brain.
• NMN and NR: another diet-adjacent compound sold for longevity, and a useful comparison for how far a mechanism and marker carry before trials weigh in.

Cautions For This Practice

Extra restraint

Everything to be aware of is here, in one place. This practice suits most healthy people; a few situations call for real care.

A 90-day rat study found no adverse effects at the highest dose, and ergothioneine was not mutagenic

In a 90-day oral toxicity study, Sprague-Dawley rats given up to 1,600 mg/kg/day, the highest dose tested, showed no adverse effects (a no-observed-adverse-effect level at that dose), and ergothioneine was negative in a bacterial reverse-mutation (Ames) test. This toxicology package supports its acceptance as a novel food in Europe and its safe status for food use. An animal toxicology study funded by a supplement manufacturer (Mironova Labs); it speaks to short-term safety, not to any benefit, and long-term safety in people taking a concentrated supplement is untested.Marone et al., A Safety Evaluation of a Nature-Identical L-Ergothioneine in Sprague Dawley Rats

Safe at the doses studied; long-term human safety is unmeasured

Ergothioneine has passed short human studies, and it has been accepted as a novel food in Europe and for food use in the United States. What has not been studied is taking a concentrated supplement for years. Food carries no such open question.

Pregnancy and breastfeeding: get it from food

The transporter for ergothioneine is active in the placenta, and the compound concentrates in the developing baby. Supplementation during pregnancy or breastfeeding has not been studied, so ordinary food such as cooked mushrooms is the safer choice at these times.

It is not a replacement for treatment that works

Because a high blood level tracks with better heart and brain health, a supplement can look like protection. It is not a substitute for the measures with real evidence: managing blood pressure and cholesterol, diet, and activity.

Forage only what you can identify

Eating more mushrooms means cultivated or store-bought ones. Some wild mushrooms are poisonous and easily confused with edible ones. The danger is picking the wrong mushroom, so leave wild foraging to people trained to identify what they pick.

Start slow, be smart, read the research, and consult a professional if you have any concerns. This is here to inform your choice, not make it for you.

Common Questions

Is ergothioneine a vitamin?

Not in the official sense. A vitamin is a compound the body cannot make and must get from food, and its lack produces a defined deficiency disease. Ergothioneine meets one half of that definition, since the body cannot make it, but low levels cause no known deficiency disease. The "longevity vitamin" phrase names a proposed category, and no official body has adopted it.

Is it safe?

At the amounts studied, it looks very safe. It was not mutagenic in a standard genetic test. A 90-day animal study found no harm even at the highest dose tested.