Lion's Mane Mushroom: The Evidence-Based Nootropic for…

Understanding Lion's Mane

Lion's Mane (Hericium erinaceus) is a white mushroom with long spines that resemble a lion's mane. It has been used for centuries in traditional Chinese and Japanese medicine (Int J Mol Sci review, 2023).

Two groups of compounds get most of the attention: hericenones, found in the fruiting body, and erinacines, found in the mycelium (Nutrients review, 2025). Some of them have been reported to cross the blood-brain barrier, mainly in lab and animal work. In lab and animal studies they stimulated nerve growth factor (NGF) and BDNF pathways (Nagano 2010; mouse study, 2021). Effects in human brains have not been measured.

Takeaway: the human evidence is a handful of small, short trials. Lion's Mane is a reasonable thing to discuss with a clinician, not a proven memory booster.

What the research found

Older adults with mild cognitive impairment. A 2009 randomized, double-blind, placebo-controlled trial gave 30 Japanese adults aged 50 to 80 four 250 mg tablets three times a day (3 g a day) for 16 weeks. The Lion's Mane group scored significantly higher on a cognitive function scale at weeks 8, 12 and 16. Four weeks after stopping, scores fell significantly. This suggests benefits may need continued use, but the trial did not test maintenance (Mori 2009). A 12-week randomized trial also reported improved MMSE scores (Saitsu 2019).
Healthy adults. In a 28-day trial of 41 healthy adults taking 1.8 g a day, only one acute test of speed (the Stroop task) reached significance (p = 0.005). The stress result was a trend (p = 0.051). Benefits for memory or focus in healthy people are not established (Docherty 2023).
Mood. In a 4-week trial, 30 women ate cookies with Lion's Mane or placebo. Depression scores fell from baseline in the Lion's Mane group. Compared with placebo, only two anxiety-related items differed significantly, and the abstract reports no significant sleep result (Nagano 2010).
Nerve repair. In rats with a crushed peroneal nerve, a water extract of fresh fruiting bodies helped hind-limb function return about 4 to 7 days sooner than in untreated controls (Wong 2011). No human nerve-injury trial was found.
Gut. In lab fermentation tests with stool from eight older donors, Lion's Mane was one of four beta-glucan-rich mushrooms tested (Mitsou 2020). No human gut trial was found.

What to look for in a product

Which part of the mushroom. Hericenones come from the fruiting body and erinacines from the mycelium. Whether a product with both works better than either alone has not been tested. Amounts vary: one review reports hericenones in fruiting bodies from under 20 to 500 µg/g dry weight and erinacines in mycelium at about 150 µg/g, so labels that do not say which part or how much tell you little (Nutrients review, 2025).
Third-party testing. Choose a brand that publishes a certificate of analysis. See the glossary entries on a COA, hericenones and erinacines.

Doses used in the trials

3 g a day (four 250 mg tablets three times daily) for 16 weeks in older adults with mild cognitive impairment (Mori 2009).
1.8 g a day for 28 days in healthy adults (Docherty 2023).
No trial we found tested 500 to 1,000 mg a day, and timing of the dose has not been studied.

Safety

Trials of up to 16 weeks reported no adverse effects on lab tests, and one author group calls oral intake safe. Long-term safety has not been studied. The trial abstracts we checked do not report side-effect rates.
People with known mushroom allergies should avoid it (Nutrients review, 2025).
In lab tests a Lion's Mane compound slowed platelet clumping, and rat studies found lower blood sugar (Mori 2010). Effects in people are not established, and no human drug-interaction study was found. Ask a doctor before use if you take blood thinners or diabetes medicines, or have surgery planned.
No safety studies in pregnancy or breastfeeding were found in the sources we checked; ask a doctor first.

Sources

Mori K et al. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment. Phytother Res 2009. PubMed 18844328
Nagano M et al. Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake. Biomed Res 2010. PubMed 20834180
Wong KH et al. Neuroregenerative potential of lion's mane mushroom in the treatment of traumatic nerve injury. Evid Based Complement Alternat Med 2011. PubMed 21941586
Saitsu Y et al. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomed Res 2019. PubMed 31413233
Docherty S et al. The acute and chronic effects of lion's mane mushroom supplementation on cognitive function, stress and mood in young adults. Nutrients 2023. PubMed 38004235
Lion's Mane review, Int J Mol Sci 2023. PubMed 37958943
Lion's Mane narrative review, Nutrients 2025. PubMed 40284172
Mori K et al. 2010, Phytomedicine: lab study of hericenone B and platelet aggregation. PubMed 20637576
Mitsou EK et al. 2020: in vitro fermentation of edible mushrooms with stool from older donors. PubMed 32570735
Li et al. 2021: mouse study of erinacine A-enriched Lion's Mane mycelium after sleep disruption. PubMed 34865649

This article is general information, not medical advice. Talk to a clinician before using Lion's Mane, especially if you take blood thinners or diabetes medicines.