HPC › Nutrition › Glossary
Lion's Mane (Hericium erinaceus) is an edible medicinal fungus whose fruiting-body compounds, hericenones, and mycelial compounds, erinacines, stimulate the synthesis of nerve growth factor in glial cells, promoting neuronal survival, maintenance, and regeneration. This NGF-induction mechanism underpins ongoing research into Lion's Mane as a dietary supplement for cognitive ageing, neurodegeneration, and mood disturbance.
The compound family that crosses the blood-brain barrier differs by extract source: erinacines (mycelium) show stronger central nervous system effects than hericenones (fruiting body).
How it works
Hericium erinaceus produces two families of neuroactive compounds. Hericenones, found in the fruiting body, and erinacines, concentrated in the mycelium, both stimulate NGF biosynthesis in glial cells. Erinacines cross the blood-brain barrier via passive diffusion and produce more potent central nervous system effects than hericenones. Among the erinacines, erinacine A promotes NGF gene expression through JNK signalling and raises the NGF-to-proNGF ratio; in rodent models this increases neuronal progenitor proliferation and new neuron formation in the hippocampal dentate gyrus. 1
The most-cited human trial randomised 30 adults aged 50 to 80 with mild cognitive impairment to either 3 g per day of Hericium erinaceus dry powder or placebo for 16 weeks. Cognitive function scale scores were significantly higher in the treatment group at weeks 8, 12, and 16 (p < 0.05), but returned toward baseline within four weeks of cessation, confirming that the effect depends on continued supplementation. 2 A pilot trial in healthy adults aged 18 to 45 found faster processing speed on the Stroop task at 60 minutes post-dose, yet also reduced delayed word recall versus placebo; the cognitive profile is therefore not uniformly positive across populations or endpoints. 3
Example
A 45-year-old professional noticing mild attentional drift selects a Lion's Mane supplement marketed as full-spectrum. The product uses fruiting-body extract, which is rich in hericenones but contains negligible erinacines, the fraction more likely to cross the blood-brain barrier. A mycelial extract would deliver the more CNS-active compounds. The label makes no mention of the distinction.
Without knowing the extract source, a consumer cannot assess whether they are purchasing the fraction supported by the strongest mechanistic evidence.
Why it matters
A 2025 systematic review of 26 studies found that Hericium erinaceus supplementation enhanced BDNF and pro-BDNF production, promoted hippocampal neurogenesis, and reduced measures of depression, anxiety, and sleep disturbance. 4 Pooled data from RCT and PCT trials showed a mean MMSE improvement of 1.17 points over placebo, a modest but consistent signal across methodologically varied studies.
The evidence base carries important limits. Human trials to date are small, short, and not always conducted in populations with cognitive impairment. Cognitive benefits observed in MCI populations have not been reliably reproduced in healthy young adults. Potential side effects, including stomach discomfort, headache, and allergic reactions, are uncommon but documented. 4 Those making supplementation decisions should weigh mechanistic plausibility and modest human evidence against the absence of large-scale confirmatory trials.
What does Lion's Mane do for the brain?+
Lion's Mane stimulates the synthesis of nerve growth factor via its bioactive compounds, hericenones and erinacines. {{cite:10.1080/21501201003735556}} In adults with mild cognitive impairment, supplementation for 16 weeks produced significant improvements in cognitive function scores versus placebo, though scores declined once supplementation stopped. {{cite:10.1002/ptr.2634}}
How long does Lion's Mane take to work?+
In the landmark 16-week RCT in adults with mild cognitive impairment, significant cognitive improvements emerged by week 8. {{cite:10.1002/ptr.2634}} A separate pilot trial found processing-speed changes within 60 minutes of a single dose in healthy adults, though effects on delayed memory measures were mixed. {{cite:10.3390/nu15224842}} Sustained benefits appear to require consistent daily use.
What is the best dose of Lion's Mane?+
The most-cited RCT used 3 g per day of Hericium erinaceus dry powder (four 250 mg tablets three times daily) for 16 weeks, with no serious adverse events recorded. {{cite:10.1002/ptr.2634}} No consensus optimal dose exists; a 2025 systematic review found benefits across varied doses, but emphasised that extract type matters as much as quantity. {{cite:10.3389/fnut.2025.1641246}}
Does Lion's Mane have side effects?+
Side effects are uncommon. Reported adverse events include stomach discomfort, headache, and allergic reactions. Existing clinical trials have small sample sizes and short durations, so rare or long-term effects cannot be fully characterised from current evidence. {{cite:10.3389/fnut.2025.1641246}} No serious adverse events were recorded in the landmark 16-week RCT in adults with mild cognitive impairment.
