Ergothioneine

The verdict

Is Ergothioneine worth taking?

Ergothioneine is the compound in this guide with the widest gap between how interesting the biology is and how little the human trial record supports it. It is graded Emerging, and that grade has nothing to do with the mechanism.

The mechanism is unusually strong. A September 2025 review in the Proceedings of the Nutrition Society concluded that ergothioneine meets the criteria for a longevity vitamin: a compound the body cannot make, actively transports inward, and concentrates in the tissues carrying the heaviest oxidative load. The body built a dedicated transporter for it, OCTN1. It does not do that for antioxidants in general. Across multiple cohorts, people with low blood ergothioneine show more cognitive impairment, more cardiovascular disease, more frailty and higher mortality.

What is missing is the trial that would move the grade. The largest one run so far put 147 adults aged 55 to 79 with subjective memory complaints on 10 mg, 25 mg or placebo for sixteen weeks. Its primary outcome was composite memory. On that measure, the only movement was a within-group improvement at 25 mg at week four that did not hold to the end of the trial. Self-reported prospective memory and time to fall asleep did improve dose-dependently and reached significance at 25 mg, and liver markers improved. That is a mixed result on mostly self-reported endpoints. A good deal of the coverage of this trial reported it as confirmed cognitive benefit. It was not.

Two details explain the outcome better than the compound does. The participants started with slightly above-average cognition and a median plasma ergothioneine around 1,150 nM, so they were neither impaired nor short of it. The authors say as much: longer trials in people with lower baseline ergothioneine or lower cognitive function are warranted. That trial has not been run.

So the file reads: a compound the body clearly wants, a deficiency signal that tracks nearly every outcome that matters, and no demonstration yet that supplementing it changes an outcome in a healthy person. Emerging is the honest grade. Eating mushrooms regularly is worth doing either way, and costs nothing.

What it does

What Ergothioneine does in the body

Neuroprotection, cognitive function support, longevity promotion through mitochondrial function enhancement and oxidative stress mitigation, anti-inflammatory activity, and cardiovascular protection. Ergothioneine is a unique sulfur-containing amino acid produced exclusively by certain fungi and soil bacteria and obtained by humans entirely through diet. It accumulates in tissues with the highest oxidative stress burden through the OCTN1 transporter, and its specific accumulation pattern strongly suggests a physiological protective role that the body prioritizes maintaining.

The evidence

What the research actually shows

Observational data is the strongest part of the file. Low blood ergothioneine is consistently associated with cognitive impairment, cardiovascular disease, frailty and increased mortality across independent cohorts. That consistency is real, and it is also the limit of what observational data can do: people who eat more mushrooms differ from people who do not in a hundred other ways.

Mechanistic work keeps strengthening. A 2025 Cell Metabolism study found ergothioneine accumulating in muscle mitochondria during exercise training and enhancing mitochondrial respiration through MPST enzyme activation. Earlier work established the OCTN1 transporter and the tissue distribution pattern that follows oxidative load.

Human retention is remarkable and well documented. In a 2017 pharmacokinetic study in 45 people, 96 to 99 percent of a single oral dose was retained rather than excreted, and whole blood concentrations were still rising three weeks after the last dose. In a year-long pilot in mild cognitive impairment, plasma was still climbing at week 52. Whatever else is unsettled, the body does not treat this as something to flush.

Interventional evidence is thin. The 147-person trial described above is the largest, and it was funded by the company that makes the branded ergothioneine used in it, which is worth knowing without being disqualifying. Beyond it there are small pilots and open-label studies. Nothing yet has shown a hard outcome changing.

Strong mechanism, strong epidemiology, thin trials. That combination is exactly what Emerging is for.

Worth checking

The one-month half-life that was never measured in humans

Almost every article about ergothioneine states that its half-life in humans is roughly one month. A 2026 review in Biotechnology Advances puts it plainly. Supplement pages, longevity newsletters and research foundations all repeat it.

Follow the citation. The figure is generally traced to a 2018 review, which in turn cites a 1982 paper. That 1982 paper is three pages on lactate and phosphate handling in rat red blood cells. It contains no half-life for ergothioneine, and its seven-day design could not have produced a one-month one.

No human elimination half-life for ergothioneine has ever been measured.

What has been measured in humans points in the same direction without needing the number. Nearly all of an oral dose is retained rather than excreted. Whole blood is still rising three weeks after the last dose and peaks around day 28. Plasma was still climbing at week 52 in the year-long pilot. The body clearly holds on to this compound for a long time.

So "about a month" is a reasonable estimate. It is an estimate drawn from a rodent study that did not report it, and it has been repeated as a measurement for the better part of a decade. If you see a product page citing a human half-life for ergothioneine, that number does not exist yet.

The open question

Daily, or a few times a week?

If a compound accumulates for a year without plateauing, dosing frequency should matter less than it does for most supplements. Nobody has tested that.

No trial has compared daily ergothioneine with intermittent ergothioneine. The 147-person trial used 10 mg and 25 mg daily. A separate year-long study used 25 mg three times a week and gave no stated rationale for the interval. Both raised blood levels substantially. Neither tells you which schedule is better, or whether the distinction matters at all.

That is the honest answer to "how often should I take ergothioneine," and it is not the answer most pages give.

Food first

Getting Ergothioneine from food

Mushrooms are effectively the only meaningful dietary source, because fungi and a few soil bacteria are the only organisms that make it. But species matters enormously here, far more than most food lists admit.

A 2026 analysis in microPublication Biology measured ergothioneine in mushrooms bought off the shelf. Converted to milligrams per 100 grams as sold:

Mushroom, as sold	Ergothioneine, mg per 100 g
Porcini, dried	90
Oyster, dried	51
Morel, dried	21
Shiitake, dried	17
Lion's mane, dried powder	14
Lobster mushroom, dried	3.9
Oyster, fresh	2.5
Shiitake, fresh	2.4
White button, dried	1.9
White button, canned	0.7
Chanterelle, dried	0.2
White button, fresh	0.02
Matsutake, dried	below detection
Lion's mane, capsules	below detection

Two caveats, then the part that is actually useful. That study tested one product per line, so the ranking is more reliable than any single number. And published figures for the same species differ by more than tenfold between studies, depending on growing substrate and analytical method, so the fresh white button figure above sits well below what others report. What survives across all of them is the shape: oyster and porcini high, white button at the bottom, chanterelle and matsutake essentially nothing. Compare dried to dried and fresh to fresh, since most of the gap between the two states is water.

Two findings from that study matter more than the numbers. Frying and pressure-cooking shiitake and oyster mushrooms raised the measured ergothioneine rather than destroying it, which suggests cooking frees some that solvent extraction alone misses. Cooking mushrooms is not a compromise with this compound. And the lion's mane capsules tested below the limit of quantitation while loose dried powder of the same species measured around 14 mg per 100 g, which is a reminder that the species on a mushroom supplement label and the contents of the capsule are two separate claims.

The practical version, from a kitchen rather than a lab: oyster mushrooms are cheap, widely available, cook in minutes and sit near the top of the list. Dried porcini rehydrated into a braise, a ragu or a risotto delivers more per gram than anything else in the table. Ergothioneine is water-soluble, so keeping the soaking liquid and using it in the dish is the prudent move, though no study has measured how much of it ends up there.

What the guide adds

The part that is not on this page

Everything above is the assessment. What the guide adds for Ergothioneine is the protocol:

• Optimal Form
• Bioavailability
• Purity Red Flags
• Stack With / Avoid

147 entries across nine categories, every one graded against the clinical literature the same way.

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About the author

Who graded this

Daniel Edlund is a Le Cordon Bleu-trained private chef in Los Angeles, a certified personal trainer and strength coach, and an internationally licensed massage therapist. Thirty years of strength training and fifteen years cooking in private estate kitchens. He is the author of The Complete Supplement Guide, which grades 147 entries against the clinical literature, and of The EASY Way to Organic Cooking, first published in 2013.

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This page is information, not medical advice. Supplements interact with prescription medication and with each other, and the right answer depends on your own bloodwork and history. Talk to your doctor before starting anything, particularly if you are pregnant, nursing, managing a health condition, or already taking medication.

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