Lion’s Mane (Hericium erinaceus) is a functional mushroom known for its shaggy appearance and brain health benefits. Lion's Mane has become a red-hot supplement in recent years due to growing interest in brain-boosting nootropics and mounting research showing it may support memory, focus, mood, and nerve regeneration. It is now considered one of the in the best nootropics on the market today.
As Lion’s Mane popularity continues to rise, more people are sharing their experiences. While many report improvements, there have also been reports of an unexpected side effect: Sleepiness.
In this article, we’ll explore this potential reaction, look at what the research says, and help you understand why Lion’s Mane might make some people feel sleepy instead of sharp. Let's get to it!
Key Takeaways
- Lion’s Mane is a popular functional mushroom known for its brain-boosting effects, especially on memory, focus, and mood.
- Many people report enhanced mental clarity and mood, but some users experience unexpected drowsiness or fatigue.
- This sleepy effect may be due to Lion’s Mane’s influence on brain function the nervous system, which can be calming for certain individuals.
- Sleepiness might also result from the mushroom's support for nerve regeneration, which can consume a good deal of energy and require recovery.
- Dose and timing matter. Some users report fewer sleepy effects when taking Lion’s Mane in the morning rather than at night.
- For others, it may make sense to take lion's mane mushroom at night and just roll with sleepy side effects. Its benefits occur over time, anyway.
Disclaimer
The information in this article is for educational purposes only and is not intended to replace professional medical advice, diagnosis, or treatment. Lion’s Mane and other supplements should always be taken under the guidance of a qualified healthcare provider, especially if you have a medical condition, take prescription medications, or are pregnant or breastfeeding. While Lion’s Mane is generally well-tolerated, individual reactions may vary. Always consult your doctor before starting any new supplement regimen.
What Is Lion’s Mane and Why Do People Take It?
Lion’s Mane (Hericium erinaceus) is a type of functional mushroom with long, white, shaggy tendrils that resemble a lion’s mane. It has been used for centuries in traditional Chinese medicine and Japanese herbalism to support brain and nerve health.
Today, Lion’s Mane is gaining popularity as a natural supplement for enhancing memory, focus, mood, and overall cognitive performance. Research suggests it may stimulate nerve growth factor (NGF), a protein involved in the growth and repair of brain cells that may confer neuroprotective properties. Many people take Lion’s Mane to:
- Support memory, focus, and cognitive performance
- Stimulate Nerve Growth Factor (NGF), aiding brain cell regeneration
- Enhance mood and reduce symptoms of anxiety and depression
- Support long-range brain health, especially in the context of age-related cognitive concerns
This is just a quick summary. If you want all the details, check out our in-depth article on Lion's Mane Benefits. But for now, let's get to the question at hand.
Does Lion’s Mane Make You Sleepy?
There is no solid clinical evidence that Lion’s Mane causes sedation or fatigue.
In fact, most research suggests it may enhance mood, and mental clarity. Of course, there have only been a few human clinical trials on Lion's Mane Mushroom, versus a lot of people taking it reporting their personal experiences.
So first, let's quickly summarize Lion's mane research studies and report on what, if any, side effects were reported by study authors. Then we'll cover some theories behind anecdotal reports of Lion's Mane and sleepiness.
Lion's Mane for Depression and Anxiety
A 2010 placebo controlled study involving 30 menopausal women found that daily Lion’s Mane (2g/day in cookies for 4 weeks) significantly reduced symptoms of depression and anxiety compared to placebo. No adverse effects were reported, and no dropouts occurred due to side effects during the trial.(1)
Learn more about adaptogens for perimenopause and menopause
Review: Lion's Mane Mushroom for Depression
One 2020 systematic review analysed three randomized, double-blind, placebo-controlled human clinical trials on Hericium erinaceus. Researchers reported that Lion's Mane appeared to hold potential for helping with depression, with brain-supportive and mood-lifting benefits. Hericium erinaceus was generally well-tolerated, with no serious safety concerns reported.(2)
Learn more about nootropics for depression
Lion's Mane Mushroom for Memory and Cognition in MCI
Researchers studied whether Lion’s Mane mushroom (Yamabushitake) could help improve mild cognitive impairment (MCI, a type of cognitive decline) in older adults. They gave 30 participants (ages 50–80) either Lion’s Mane tablets or a placebo for 16 weeks. The group taking Lion’s Mane showed steady improvement in memory and thinking skills over time compared to placebo. No adverse effects or side effects were reported during the study, and no safety issues emerged during that follow-up period either.(3)
Learn more about nootropics for memory
Lion's Mane for Age-Related Cognitive Concerns
Researchers tested whether Lion’s Mane mycelia (mycelia are kind of like mushroom "roots") capsules could help people with mild Alzheimer’s. In the 49-week study, 49 participants were split into two groups: one took three capsules a day (350 mg each, with 5 mg/g erinacine A) or placebo. The group taking Lion’s Mane showed improved memory and thinking, better daily functioning, and better contrast vision compared to placebo.
Side effects: This is the one study that linked lion's mane to side effects. It was mostly well tolerated, but four subjects dropping out due to mild side effects: Digestive discomfort, nausea, skin rash. Still, overall the researchers concluded that Lion's Mane was safe and well-tolerated.(4)
Theories Why Lion’s Mane Might Cause Fatigue in Some People
Although not supported by clinical trials, some individuals report drowsiness or fatigue after taking Lion’s Mane. Possible explanations include:
- Nervous system calming: Lion’s Mane may support parasympathetic activity ("rest and digest"), making some users feel more relaxed or even sleepy.
- Synergy with other supplements: If taken with calming herbs, sleep aids, or medications, Lion’s Mane might contribute to a more sedative effect.
- Individual response: People with low cortisol or thyroid activity may be more likely to feel fatigued when taking relaxing or adaptogenic supplements.
Note: Correlation is not always causation. In other words, just because you experience a side effect while taking a supplement, does not mean that supplement is responsible for the side effect. So people feeling sleepy on Lion's Mane may also be overworked, stressed, struggling with sleep disorders, consuming too much caffeine, or simply not getting enough deep regenerative sleep.
Learn more about today's top natural sleep supplements
Tips for Reducing Sleepiness from Lion’s Mane
- Take it at night: If it causes drowsiness, you can take Lion's Mane before bed or in the evening instead of during the day. This can help align with your sleep wake cycle, and may even help improve sleep quality.
- Lower the dose: Start with a lower dosage (e.g., 250–500 mg/day) and increase gradually only if needed. Sometimes the sleepiness fades as your body adjusts. Learn more about Lion's Mane mushroom dosage
- Split the dose: Try dividing your daily intake into two smaller doses, one in the morning and one in the evening, to prevent a strong sedative effect all at once.
- Avoid combining with other calming supplements: Lion’s Mane may interact with other herbs or supplements with sedative effects (like ashwagandha, L-theanine, or melatonin). Try taking Lion’s Mane by itself to see if that reduces drowsiness.
- Choose a different form: Some people react differently to fruiting body vs. mycelium-based supplements. If you’re getting sleepy from one form, try switching to another to see if it makes a difference.
- Eat something with it: Taking Lion’s Mane with food might slow its absorption and soften its effects, making drowsiness less noticeable.
- Lion's mane can be consumed in many forms, such as raw, cooked, or as a tea or supplement - we, of course, would recommend our Mind Lab Pro supplement!
Best Supplement with Lion's Mane Mushroom
Mind Lab Pro®
If you want to try a high quality Lion's Mane supplement with minimal risk of sleepy side effects, consider Mind Lab Pro®. It's a full-spectrum brain booster that enhances many different cognitive functions. And it includes caffeine-free energizers to counteract any drowsiness or mental fatigue you may experience from Lion's Mane.
Mind Lab Pro® Ingredients: Citicoline (CDP Choline) dosage 250mg per serving, Phosphatidylserine (PS) 100mg (from sunflower lecithin), Bacopa monnieri 150mg (24% bacosides), Organic Lion's Mane Mushroom 500mg (fruit and mycelium), Maritime Pine Bark Extract 75mg (95% proanthocyanidins), N-Acetyl L-Tyrosine 175mg, L-Theanine 100mg per serving, Rhodiola rosea 50mg (3% rosavins and 1% salidrosides), NutriGenesis® Vitamin B6 (2.5 mg), Vitamin B9 (100 mcg), Vitamin B12 (7.5 mcg)
Mind Lab Pro® (MLP®) is today's best nootropic supplement. It is also backed by three well-designed human clinical trials where researchers suggested it:
- Was linked with significant improvements (compared to placebo) in information processing speed.(5)
- Improved performance across all memory functions tested (versus placebo), especially immediate and delayed recall memory.(6)
- Helped the brain's different regions work together more efficiently.(7)
Read all the details on Mind Lab Pro clinical studies
Summary
Lion’s Mane is a popular functional mushroom. The benefits of lion's mane mushroom supplements include support for brain health, sharper memory, mood balance and anxiety reduction. It may even boost mental clarity and enhance focus. While most research highlights its neurological and cognitive benefits, some users report feeling sleepy or drowsy after taking it.
Clinical studies generally do not list sedation as a side effect, and many people actually take Lion’s Mane to boost focus and bust brain fog.
So does Lion's Mane make you sleepy? Everybody's physiology is different, so the best answer is that yes, in some cases consuming lion's mane might make you sleepy. But that shouldn't discourage you from trying this remarkable nootropic mushroom.
Instead, consider some of the practical tips in this guide to reduce risk of sleepy side effects, such as careful dosing, taking Lion's Mane before bed, or making sure you take it from a premium-quality stack like Mind Lab Pro.
If sleepiness persists or interferes with daily life, it may be worth switching to another nootropic or adaptogen, or consulting a healthcare professional to tailor your supplementation plan.
References
- Nagano, M., Shimizu, K., Kondo, R., & Hayashi, C. (2010). Reduction of depression and anxiety by 4 weeks Hericium erinaceus intake. Biomedical Research, 31(4), 231–237. Link
- Chong PS, Fung ML, Wong KH, Lim LW. Therapeutic Potential of Hericium erinaceus for Depressive Disorder. Int J Mol Sci. 2019 Dec 25;21(1):163. Link
- Mori, K., Inatomi, S., Ouchi, K., Azumi, Y., & Tuchida, T. (2009). Improving cognitive function with Lion’s Mane mushroom: A double-blind placebo-controlled clinical trial. Phytotherapy Research, 23(3), 367–372. Link
- Li IC, Chang HH, Lin CH, Chen WP, Lu TH, Lee LY, Chen YW, Chen YP, Chen CC, Lin DP. Prevention of Early Alzheimer's Disease by Erinacine A-Enriched Hericium erinaceus Mycelia Pilot Double-Blind Placebo-Controlled Study. Front Aging Neurosci. 2020 Jun 3;12:155. Link
- Utley A, Gonzalez Y, Imboden CA. The Efficacy of A Nootropic Supplement on Information Processing in Adults: A Double Blind, Placebo Controlled Study. Biomed J Sci & Tech Res 49(1)-2023. BJSTR. MS.ID.007746. Link
- Abbott-Imboden C., Gonzalez Y., Utley A. (2023). Efficacy of the nootropic supplement Mind Lab Pro on memory in adults: Double blind, placebo-controlled study. Human Psychopharmacology: Clinical and Experimental, e2872. Link
- O’Reilly, D., Bolam, J., Delis, I., & Utley, A. (2025). Effect of a Plant-Based Nootropic Supplement on Perceptual Decision-Making and Brain Network Interdependencies: A Randomised, Double-Blinded, and Placebo-Controlled Study. Brain Sciences, 15(3), 226. Link
