Lion’s mane (Hericium erinaceus) is a mushroom belonging to the Hericiaceae family, recognized by its soft pendant projections (spines) measuring 1–4 cm in length. Lion’s mane typically requires a substrate like dead wood to grow, but it can also be cultivated on other substrates such as artificial logs or in a liquid matrix for larger-scale production. Lion’s mane can be used for both culinary and medicinal purposes. Its mature fruiting body has a fleshy, tough, and watery texture, and it’s known for its seafood-like flavor, reminiscent of crab, shrimp, or lobster.^[5][6]

Lion’s mane contains a range of bioactive compounds, including high-molecular-weight substances like polysaccharides (e.g., beta-glucans) and low-molecular-weight compounds such as terpenoids, which usually require the use of solvents such as methanol or ethyl acetate to be extracted due to their limited solubility in water.^[5][6]

Notably, lion’s mane has been used for a long time in traditional Chinese medicine in Asia, but it was initially described in North America and later in Europe.^[5]

Lion’s mane has gained recent popularity due to its potential neuroprotective and antioxidant properties, which may improve cognitive function and symptoms associated with neurodegenerative conditions such as dementia and Alzheimer’s disease. However, the existing clinical trial evidence supporting these claims remains limited.

In one randomized controlled trial (RCT), individuals with mild Alzheimer's disease were given three 350 mg capsules daily of Hericium erinaceus mycelia enriched with 5 mg/g of erinacine (an active compound in lion’s mane) for 49 weeks. Although the group taking lion’s mane scored higher than the placebo group in the Instrumental Activities of Daily Living (IADL) test compared to baseline, no significant differences were observed in other tests used to assess mild to moderate dementia (MMSE, CASI, and NPI).^[2] Another clinical study, using 3 g of lion's mane powder in capsule form, showed notable improvements in cognitive function for individuals with general mild cognitive decline. Cognitive improvement relative to the control group was observed, with the degree of improvement increasing over time. However, cognitive function reverted to baseline levels 4 weeks after the discontinuation of lion’s mane treatment, suggesting the need for a continuous intake to maintain its effect.^[1] Additionally, one RCT involving healthy participants taking 3.2 g of lion’s mane daily demonstrated improved scores in the Mini-Mental State Examination (MMSE) test compared to the placebo group. Although this may indicate lion’s mane’s potential for preventing cognitive decline in older adults, other tests of cognitive function in this study did not yield similar results.^[3]

Lion’s mane is also being investigated for its potential to reduce symptoms of anxiety and depression. Two studies, one involving menopausal women^[4] and another including overweight or obese individuals,^[7] reported improvements following supplementation with lion's mane. However, both studies had limitations in their design and targeted people belonging to specific demographic groups rather than the general population.^[8]

The side effects of lion’s mane are still under investigation, but adverse effects have not typically been seen at the recommended dosage. The symptoms reported by study participants have included nausea, abdominal discomfort, diarrhea, and skin rash.^[2][1]

Lion’s mane contains several bioactive compounds that contribute to its properties. Notably, hericenones (primarily found in the mushroom’s fruiting body) and erinacines (concentrated in the mushroom’s mycelia) have been shown to stimulate the synthesis of nerve growth factor (NGF) in astrocytes (a type of non-neuronal brain cell) located in the hippocampus.^[9] NGF is responsible for regulating neuronal cell differentiation, proliferation, and survival in the brain, and increased NGF levels have been associated with improved neurogenesis and neuroplasticity. There are different types of hericenones, and most of them appear to contribute to the biosynthesis of NGF. Hericenone B has also demonstrated potential in preventing thrombosis (blood clots) and increasing blood flow, both of which play a role in dementia.^[3][8] Additionally, lion’s mane has shown the capacity to enhance the myelination (production of myelin sheath) of neurons in vitro.^[10]

Another key compound in lion’s mane is beta-glucan. In vitro studies have suggested that beta-glucans may have two beneficial effects: a cholesterol-lowering effect and an antitumor effect. The latter is due to the activation of macrophages, which are crucial components of the innate immune system and which play a role in the neuroregeneration processes within the central nervous system.^[3]

Animal studies have also observed that lion’s mane might exhibit antidepressant-like effects by restoring depleted serotonin, norepinephrine, and dopamine levels in the hippocampi of restraint-stressed mice. However, the precise mechanism through which lion’s mane modulates the concentrations of these neurotransmitters remains unclear.^[8]