The short answer
Not convincingly. Five small trials in healthy adults have been published. Two found a slightly quicker response on one or two tasks an hour after a single dose, and three found no overall effect, including the only one to give a large daily dose for four weeks. There is no good evidence it sharpens focus in healthy people.
Weak evidence
Mixed or very small human studies, or studies without a proper placebo group. How we grade
On this page
What did the trials in healthy adults find?
Five trials have tested lion’s mane on focus, memory or thinking speed in healthy adults. Taken together they point to little or no effect:
| Trial | Who | Dose | Result |
|---|---|---|---|
| Docherty 2023, UK | 41 adults aged 18 to 45 | 1.8 g a day for 28 days | Faster on the Stroop attention test 60 minutes after the first dose; no lasting improvement after 28 days |
| La Monica 2023, USA | 40 adults aged 18 to 50 | 1 g, single dose | Faster reaction times on some tasks over 2 hours |
| Surendran 2025, UK | 18 adults aged 18 to 35 | 3 g of a 10:1 extract, single dose | No overall effect on thinking or mood; one dexterity test improved |
| Grozier 2022, USA | 24 college-age adults | 10 g a day for 4 weeks | No effect on thinking tasks |
| Evans 2026, USA | 10 adults aged 18 to 55 | 2 g a day for 28 days | No significant change in attention or task switching |
Why is the evidence graded weak?
Because the positive findings are small, scattered across different tasks, and not repeated. When a study runs a dozen cognitive tests, one or two will often come out “significant” by chance, and the authors of the UK pilot trial said their results should be read with caution. The two trials that found something both tested a single dose over one to two hours, and the four-week trials found nothing lasting. One of the positive single-dose trials was part-funded by an ingredient supplier.
The most telling result may be Grozier 2022: 10 g a day, three to ten times the dose in other trials, for four weeks, with no effect on thinking.
Why might it work better in older adults?
The trials that found memory benefits were in older people with some decline, where there is more room to improve. In healthy young adults, performance on these tests is already near its best, so a modest effect is harder to detect and may not exist. See memory in older adults for those trials.
What should you take from this?
If you want sharper focus for work or study, the evidence for lion’s mane is no better than for many cheaper habits, and much weaker than for sleep, exercise or a cup of coffee. If you try it anyway, use a dose that matches the trials (1 to 3 g a day) and judge it honestly over a month. See dosage.
Keep reading
- Lion's mane for anxiety and depression: the evidence
Two small studies suggest lion's mane may ease anxiety and low mood, but neither is strong. What they found, their limits and who should be careful.
Weak - Lion's mane for nerve damage and neuropathy: what the evidence shows
Lion's mane helped injured nerves recover in rats and mice, but it has never been tested for nerve damage or neuropathy in people. What the studies found.
None - Does lion's mane help memory? What the trials show
Three small trials in older adults found modest memory gains with lion's mane. What they tested, the doses used, and why the evidence is still thin.
Moderate
Common questions
Is lion's mane a nootropic?
It is sold as one, but the trials in healthy adults do not support the label. The effects seen were small, limited to one or two tasks, and not repeated in other studies.
Does lion's mane mushroom coffee help you focus?
Any effect on focus from mushroom coffee is almost certainly the caffeine. Most products contain far less lion's mane than the 1 to 3 g used in trials, and even those doses did little for healthy adults.
Can lion's mane help with ADHD?
No trial has tested lion's mane in people with ADHD. Do not stop or change prescribed ADHD medication in favour of it.
References
- Docherty S et al. 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.pubmed.ncbi.nlm.nih.gov
- La Monica MB et al. Acute effects of naturally occurring guayusa tea and Nordic lion's mane extracts on cognitive performance. Nutrients, 2023.pubmed.ncbi.nlm.nih.gov
- Surendran G et al. 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. Frontiers in Nutrition, 2025.pubmed.ncbi.nlm.nih.gov
- Grozier CD et al. Four weeks of Hericium erinaceus supplementation does not impact markers of metabolic flexibility or cognition. International Journal of Exercise Science, 2022.pubmed.ncbi.nlm.nih.gov
- Evans C et al. A pilot proof-of-concept study to evaluate the physiological and cognitive impacts of Hericium erinaceus on healthy adults. Nutrients, 2026.pubmed.ncbi.nlm.nih.gov
First published 3 November 2026. Spotted an error? Tell us and we'll correct it. Read our editorial policy.