Quick answer
In the trials that found a difference, it took weeks. Adults over 50 taking about 3 g a day scored higher than placebo from week 8 of a 16-week trial, and the gain had faded 4 weeks after they stopped. Single doses tested within 2 hours gave mixed results.1,2,3,4
Key facts
- Differences from placebo were reported at weeks 8, 12 and 16 of the 16-week trial.1
- Scores dropped significantly in the 4 weeks after that trial ended.1
- A 4-week trial of 10 g a day in young adults found no change at all.5
- The longest trial ran 49 weeks, with checks at weeks 13, 25 and 49.6
What changed, and when
The trials checked people at very different points, from one hour after a single dose to almost a year of daily use. Arranged by time, the pattern is plain: the short checks found little, and the clearer results came after two months or more.1,2,6
| When checked | Amount and group | What was measured | Result |
|---|---|---|---|
| 1 hour | 1.8 g, adults aged 18 to 45 | Attention, memory and mood tasks | One task faster, word recall worse, most unchanged |
| 90 minutes | 3 g of extract, adults aged 18 to 35 | Thinking and mood | No overall change |
| 1 and 2 hours | 1 g, adults aged 18 to 50 | Reaction time and working memory | Small changes from baseline, not compared with placebo |
| 4 weeks | 10 g a day, college-age adults | Thinking under fatigue, fuel use | No change |
| 4 weeks | 2 g a day, women | Complaint, mood and sleep questionnaires | Two complaint items lower than placebo |
| 28 days | 1.8 g a day, adults aged 18 to 45 | Stress and mood ratings | A trend toward lower stress that was not significant |
| 8, 12 and 16 weeks | About 3 g a day, adults aged 50 to 80 | Cognitive scale | Higher than placebo at each check |
| 12 weeks | 3.2 g a day, adults over 50 | Three thinking tests | One slightly higher than placebo |
| 49 weeks | 1.05 g a day of mycelium, older adults under medical care | Thinking tests | Some better than placebo |
The effect behind the graded claim
May support memory and thinking test scores in adults over 50 at about 3 g a day of fruiting body powder; not shown in younger adults*1,2,4,5,8
Early evidence
Two small Japanese trials. In 30 adults aged 50 to 80 whose memory and thinking had been assessed as mildly below normal for their age, about 3 g a day of fruiting body powder for 16 weeks raised scores on a cognitive scale more than placebo at weeks 8, 12 and 16, and the gain faded within 4 weeks of stopping. In 31 adults over 50, 3.2 g a day for 12 weeks gave a slightly higher result than placebo on one screening test and no difference on two others. In younger adults, 10 g a day for 4 weeks changed nothing measured, and single doses of 1 to 3 g gave mixed results.
Amount studied: About 3 to 3.2 g a day of fruiting body powder for 12 to 16 weeks
In the 16-week trial, scores differed from placebo at week 8 and again at weeks 12 and 16, rising the longer people took it.1
Two small trials cannot say how many weeks are enough for any one person. They do show that the measured change came after weeks of taking it every day, not after a few days.1,8
What happens when you stop
Four weeks after that 16-week trial ended, the lion's mane group's scores had fallen significantly.1
That is the only trial we found that checked people after they stopped. If the effect is real, it seems to last only while lion's mane is being taken.1
Why it may take time
Little is known about how the human body handles lion's mane. The best figures come from rats, where only about 15% of one erinacine was absorbed from a mycelium extract, and the authors of a 28-day human trial note that no human absorption data exist.2,9
How long people have taken it
Daily use has been studied for up to 16 weeks in older adults, where laboratory tests showed no adverse effect, and for 49 weeks in older adults under medical care. In the 49-week trial, 3 people taking lion's mane stopped because of stomach discomfort, nausea or a skin rash. We found no long-term studies in healthy younger adults.1,6
Questions people ask
How long should you take lion's mane?
The fruiting body trials that found a difference ran 12 to 16 weeks at about 3 g a day. Shorter trials in younger adults found little, and in the one trial that followed people after stopping, the gain was gone within 4 weeks.1,5,8
Does lion's mane work immediately?
Not in any clear way. Single doses were tested 1 to 2 hours later, and the results were mixed: small changes on some tasks, none on others.2,3,4
Is it safe to take lion's mane every day?
Trials gave it daily for up to 16 weeks in older adults, with mild stomach complaints as the main problem, and NIH's LiverTox rates it an unlikely cause of liver injury. Longer daily use has been studied only in people under medical care, so ask your doctor if you plan to take it for months.1,6,12
See what we make
Every product shows its whole label and what its lab report covers. The store opens soon.
Sources
- Mori K, Inatomi S, Ouchi K, Azumi Y, Tuchida T. Improving effects of the mushroom Yamabushitake (Hericium erinaceus) on mild cognitive impairment: a double-blind placebo-controlled clinical trial. Phytother Res. 2009;23(3):367-372. Opened 2026-10-07.
- Docherty S, Doughty FL, Smith EF. 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;15(22):4842. Opened 2026-10-07.
- La Monica MB, Raub B, Ziegenfuss EJ, et al. Acute effects of naturally occurring guayusa tea and Nordic lion's mane extracts on cognitive performance. Nutrients. 2023;15(24):5018. Opened 2026-10-07.
- Surendran G, Saye J, Binti Mohd Jalil S, 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. Front Nutr. 2025;12:1405796. Opened 2026-10-07.
- Grozier CD, Alves VA, Killen LG, Simpson JD, O'Neal EK, Waldman HS. Four weeks of Hericium erinaceus supplementation does not impact markers of metabolic flexibility or cognition. Int J Exerc Sci. 2022;15(2):1366-1380. Opened 2026-10-07.
- Li IC, Chang HH, Lin CH, et al. Prevention of early Alzheimer's disease by erinacine A-enriched Hericium erinaceus mycelia pilot double-blind placebo-controlled study. Front Aging Neurosci. 2020;12:155. Opened 2026-10-07.
- Nagano M, Shimizu K, Kondo R, et al. Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake. Biomed Res. 2010;31(4):231-237. Opened 2026-10-07.
- Saitsu Y, Nishide A, Kikushima K, Shimizu K, Ohnuki K. Improvement of cognitive functions by oral intake of Hericium erinaceus. Biomed Res. 2019;40(4):125-131. Opened 2026-10-07.
- Hu JH, Li IC, Lin TW, et al. Absolute bioavailability, tissue distribution, and excretion of erinacine S in Hericium erinaceus mycelia. Molecules. 2019;24(8):1624. Opened 2026-10-07.
- Mori K, Kikuchi H, Obara Y, et al. Inhibitory effect of hericenone B from Hericium erinaceus on collagen-induced platelet aggregation. Phytomedicine. 2010;17(14):1082-1085. Opened 2026-10-07.
- Nakatsugawa M, Takahashi H, Takezawa C, et al. Hericium erinaceum (yamabushitake) extract-induced acute respiratory distress syndrome monitored by serum surfactant proteins. Intern Med. 2003;42(12):1219-1222. Opened 2026-10-07.
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Lion's Mane. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases. Last update January 5, 2024. Opened 2026-10-01.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.