GradedHealth

Lion's mane mushroom for memory: what the trials found

Small trials suggest lion's mane may slightly improve memory test scores in older adults, but healthy young adults saw little benefit.

Published October 2026

Short answer

The evidence is early and mixed. A few small trials found slight gains on memory tests in older adults, especially those with mild memory problems, but most trials in healthy adults found no clear benefit. Evidence grade C (Limited). Several small randomised trials with mixed results; downgraded for small total sample (under 250 people) and inconsistency across tests, and no meta-analysis exists.

Key takeaways

  • In 30 older adults with mild memory problems, 16 weeks of lion's mane improved scores on a dementia rating scale, and scores slipped back after they stopped taking it [1].
  • A 12-week trial of 31 healthy adults over 50 found a small rise in one cognitive score (about 0.8 points of 30) with lion's mane, but two other memory tests showed no difference [2].
  • In 41 people with mild Alzheimer's disease, 49 weeks of an erinacine-rich mycelium extract kept daily-function scores higher than placebo, but the main thinking tests did not differ significantly between groups [3].
  • Trials in healthy younger adults were mostly null, though a single 1.8 g dose sped up one reaction-time task [4].
  • Side effects are usually mild — stomach upset, headache, and rarely allergic reactions [5].

The short version

Lion's mane is a mushroom sold as a supplement for memory and brain health, and the trials so far give a mixed picture [5]. In small studies it modestly improved scores on thinking tests in older adults, especially those with mild memory problems or early Alzheimer's disease [1][3]. Trials in healthy younger adults have mostly found no clear benefit [6][7].

What the studies show

In one of the earliest trials, 30 adults aged 50 to 80 with mild cognitive impairment took 3 g of dried lion's mane powder daily for 16 weeks [1]. Their scores on a dementia rating scale rose more than the placebo group's at weeks 8, 12 and 16, and slipped back down in the month after they stopped taking it [1].

A 12-week trial in 31 healthy adults over 50 compared 3.2 g a day of fruiting-body powder with a placebo [2]. Scores on one 30-point cognitive scale rose slightly more with lion's mane — 29.19 to 30.00, versus 28.73 to 29.53 on placebo — but two other memory tests showed no difference between the groups [2].

In 41 people with mild Alzheimer's disease, a 49-week trial tested a mycelium extract rich in erinacine A [3]. The extract group's scores on one thinking test improved slightly, and their daily-function scores held up better than the placebo group's, but the main thinking tests did not differ significantly between groups [3].

Trials in healthy younger adults have been mostly null. In a 28-day study of 41 adults aged 18 to 45, a single 1.8 g dose sped up one reaction-time task (688 ms versus 738 ms), but other thinking tests did not improve, and the placebo group did better on one memory task at the end [4]. A 2025 crossover trial in 18 adults found no overall change in cognition or mood from a single 3 g extract dose [6], and 10 g a day for 4 weeks had no effect in a study of 24 college-age adults [7]. A crossover trial of 40 adults did see small improvements on a few attention measures after a single 1 g dose [8].

Smaller trials have also looked at mood and sleep. A 4-week placebo-controlled trial in 30 menopausal women found lower depression and symptom scores with lion's mane [9]. An 8-week study in 77 adults with overweight or obesity reported better depression, anxiety and sleep scores in the supplement group, but there was no significant between-group difference on its depression scale [10].

The nuances

The positive results come from older adults who already had some cognitive trouble, not from healthy young people [1][3]. The trials used very different products too: dried fruiting-body powder, erinacine-rich mycelium extracts, cookies and baked muffins, at daily amounts from 1.8 g to 10 g [2][3][7]. Fruiting bodies and mycelium contain different active compounds, so supplements are not interchangeable [3].

Side effects in the trials were mostly mild: stomach discomfort, nausea, diarrhea and headache [5]. Four people in the Alzheimer's trial stopped because of abdominal discomfort, nausea or a skin rash [3]. Rare allergic reactions have been reported, so people with a mushroom allergy should avoid lion's mane [5]. There is no safety data for pregnancy or breastfeeding, and the trials excluded pregnant and breastfeeding women [2]. No human studies have tested interactions with medicines; if you take prescription drugs, ask a doctor or pharmacist first.

What this means for you

Lion's mane is not an established memory treatment — it is a supplement with early, mixed evidence, and the best results so far come from people with existing cognitive problems [3][5]. The Alzheimer's study was designed as a pilot, and its authors called for a larger trial to confirm the findings [3]. If you try it, know that studies used 1.8 g to 10 g a day, but products vary and a given supplement may not match what was tested [2][7]. For memory problems that affect daily life, seeing a doctor is the safer first step.

Go deeper

  • Lion's Mane — Small trials suggest lion's mane mushroom may slightly improve memory and thinking in older adults, especially those with mild memory problems or early Alzheim…

References

  1. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial.. Phytother Res, 2009.
  2. Improvement of cognitive functions by oral intake of Hericium erinaceus.. Biomed Res, 2019.
  3. Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study.. Front Aging Neurosci, 2020.
  4. The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study.. Nutrients, 2023.
  5. Benefits, side effects, and uses of Hericium erinaceus as a supplement: a systematic review.. Front Nutr, 2025.
  6. Acute effects of a standardised extract of Hericium erinaceus (Lion's Mane mushroom) on cognition and mood in healthy younger adults: a double-blind randomised placebo-controlled study.. Front Nutr, 2025.
  7. Four Weeks of Hericium erinaceus Supplementation Does Not Impact Markers of Metabolic Flexibility or Cognition.. Int J Exerc Sci, 2022.
  8. Acute Effects of Naturally Occurring Guayusa Tea and Nordic Lion's Mane Extracts on Cognitive Performance.. Nutrients, 2023.
  9. Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake.. Biomed Res, 2010.
  10. Hericium erinaceus Improves Mood and Sleep Disorders in Patients Affected by Overweight or Obesity: Could Circulating Pro-BDNF and BDNF Be Potential Biomarkers?. Evid Based Complement Alternat Med, 2019.