Ergothioneine Benefits: What It Is, Food Sources, Dosage and Safety

Ergothioneine is an antioxidant your body gets only from food, mostly mushrooms, and it has its own dedicated transporter that pulls it into cells and holds it there. Blood levels fall after age 60, and in human studies daily ergothioneine improved sleep quality while ergothioneine-rich mushrooms supported memory in older adults. This guide covers what ergothioneine is, what the research shows, food sources, dosage and safety.

It is educational, not medical advice.

Key Takeaways

• Diet only: the body cannot make ergothioneine; it absorbs it from food through a transporter called OCTN1 and keeps it in tissues.
• Levels fall with age: whole blood ergothioneine drops significantly after 60, and lower plasma levels track with faster decline in memory and thinking in older adults.
• Sleep: 8 mg a day for 16 weeks improved subjective sleep quality compared with placebo in a double-blind trial.
• Memory: eating ergothioneine-rich oyster mushrooms four times a week for 12 weeks improved delayed word recall in adults aged 60 to 80.
• Safety: the European Food Safety Authority judged synthetic L-ergothioneine safe, including for pregnant and breastfeeding women.

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What Is Ergothioneine?

Ergothioneine (often written L-ergothioneine or EGT) is a sulfur-containing amino acid made by fungi and some bacteria. Humans cannot make it, so all of it comes from diet. In 2005, researchers found that a protein called OCTN1 is a dedicated ergothioneine transporter: cells that carry it absorb ergothioneine efficiently and hold on to it, while cells without it barely take any up (Gründemann 2005). Researchers who gave it to volunteers noted that the way the body takes it up and retains it suggests an important physiological role (Cheah 2017).

How Ergothioneine Works

Ergothioneine is an antioxidant that works inside cells. It tends to build up in tissues exposed to more oxidative stress and inflammation (Cheah 2016). When healthy volunteers took pure ergothioneine, it was absorbed readily, blood levels rose and stayed high, little was lost in urine, and markers of oxidative damage trended down (Cheah 2017). It works alongside the body's main antioxidant, glutathione; see Best Glutathione Supplement by Form. For how the two antioxidants differ, see our guide to ergothioneine vs glutathione.

Ergothioneine Benefits: What Human Studies Show

Healthy brain aging

In older adults, whole blood ergothioneine fell significantly beyond age 60, and people with memory decline had lower plasma levels than others of the same age (Cheah 2016). In 470 older adults followed for up to five years, lower plasma ergothioneine was linked to faster decline in memory, attention, processing speed and daily function (Wu 2022). These studies measured the levels people already had; the trials below gave ergothioneine or ergothioneine-rich food.

Memory and mood

In a 12 week randomized trial of 80 healthy adults aged 60 to 80, eating four portions a week of oyster mushrooms, which are rich in ergothioneine, improved delayed word recall and word recognition and kept mood steadier compared with placebo (Cha 2026).

Sleep quality

An earlier trial found that 20 mg of ergothioneine a day for four weeks improved sleep quality. A follow-up double-blind trial then tested a lower dose: 8 mg a day for 16 weeks improved subjective sleep quality compared with placebo (Okumura 2025).

Food Sources of Ergothioneine

Mushrooms are the richest dietary source, and levels vary widely by species, from 0.15 to 7.27 mg per gram of dried mushroom in one analysis (Kalaras 2017). Oyster mushrooms, used in the memory trial above, are one rich source. For the mushrooms themselves, see Adaptogenic Mushrooms: What They Are, Benefits and How to Take Them.

Shiitake is one of the mushrooms that contains ergothioneine; our guide to shiitake mushroom benefits covers what trials in healthy adults measured.

How Much Ergothioneine to Take

The sleep trials used 5 to 20 mg a day, and effects were measured after 4 to 16 weeks. Because the body keeps ergothioneine in tissues, levels build over weeks of steady use, so daily consistency matters more than timing.

Ergothioneine Side Effects and Safety

The European Food Safety Authority judged synthetic L-ergothioneine safe as a novel food, including for infants, young children and pregnant and breastfeeding women at the intended use levels, with wide safety margins (EFSA 2017). Talk to a clinician first if you take medication or have a medical condition.

Taking Ergothioneine With Other Supplements

Ergothioneine is often paired with other brain and energy nutrients. PQQ supports mitochondria; see PQQ Benefits. Citicoline supports acetylcholine and brain cell membranes; see Citicoline vs Alpha GPC. Glutathione works as a partner antioxidant (see our glutathione ingredient page), and our Glutathione Nasal Spray delivers it directly. For the bigger picture, read our cognitive health and mental clarity hub and Best Anti-Aging Supplements Backed by Human Research.

Coming soon from Synchronicity: our Brain Energy Capsules are planned with L-ergothioneine 25 mg plus citicoline 500 mg and PQQ 20 mg per serving, with no caffeine. Join the waitlist on the product page to hear when they launch; no payment is taken.

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Citicoline 500 mg, PQQ 20 mg and L-ergothioneine 25 mg per serving, with no caffeine or other stimulants.

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Frequently Asked Questions

What does ergothioneine do?

It is an antioxidant the body absorbs from food and stores in tissues with a dedicated transporter. It is studied for healthy brain aging, sleep quality and protection from oxidative stress.

What foods are high in ergothioneine?

Mushrooms are the richest source, with levels that vary widely by species; oyster mushrooms are one rich source.

When is the best time to take ergothioneine?

Any time of day. It builds up in tissues over weeks, so taking it daily matters more than timing.

Is ergothioneine safe to take?

The European Food Safety Authority judged synthetic L-ergothioneine safe, including for pregnant and breastfeeding women.

Does ergothioneine help with aging?

Levels fall after 60, and lower levels are linked to faster decline in memory and thinking. Ergothioneine-rich mushrooms improved memory in adults over 60 in a 12 week trial.

How much ergothioneine should I take?

Trials used 5 to 20 mg a day. Use the amount on your product's label.

Is ergothioneine the same as glutathione?

No. Both are sulfur-containing antioxidants, but the body makes glutathione and must get ergothioneine from food.

Sources

• Gründemann D, and others. Discovery of the ergothioneine transporter. Proc Natl Acad Sci U S A. 2005. PubMed 15795384
• Cheah IK, and others. Ergothioneine levels in an elderly population decrease with age and incidence of cognitive decline. Biochem Biophys Res Commun. 2016. PubMed 27444382
• Cheah IK, and others. Administration of pure ergothioneine to healthy human subjects: uptake, metabolism, and effects on biomarkers of oxidative damage and inflammation. Antioxid Redox Signal. 2017. PubMed 27488221
• Wu LY, and others. Low plasma ergothioneine predicts cognitive and functional decline in an elderly cohort attending memory clinics. Antioxidants (Basel). 2022. PubMed 36139790
• Cha S, and others. A randomised controlled study to investigate the cognitive, mood, metabolic and anti-inflammatory effects of oyster mushroom in older adults. Food Funct. 2026. PubMed 42299921
• Okumura H, and others. Estimation and validation of an effective ergothioneine dose for improved sleep quality using a physiologically based pharmacokinetic model. Food Sci Nutr. 2025. PubMed 40475978
• Kalaras MD, and others. Mushrooms: a rich source of the antioxidants ergothioneine and glutathione. Food Chem. 2017. PubMed 28530594
• EFSA Panel on Dietetic Products, Nutrition and Allergies. Statement on the safety of synthetic L-ergothioneine as a novel food. EFSA J. 2017. PubMed 32625352

These statements have not been evaluated by the Food and Drug Administration. This content is for education and is not medical advice. Our products are not intended to diagnose, treat, cure or prevent any disease. Talk with a healthcare provider before starting a new supplement if you are pregnant, breastfeeding or taking medication.