What Is Lion's Mane? Uses, Research & Side Effects

What is Lion's Mane? It's an edible mushroom, Hericium erinaceus, that has gone from a niche ingredient to something you see in coffees, capsules, gummies and now gum. This guide covers what Lion's Mane looks and tastes like, how people use it, what the research does and doesn't show, possible side effects, and how to read a label before you buy.

What is Lion's Mane?

Lion's Mane is an edible mushroom with the scientific name Hericium erinaceus. It goes by many other names, including bearded tooth mushroom, monkey head mushroom, pom pom mushroom and, in Japan, yamabushitake. Memorial Sloan Kettering's integrative medicine database notes that it is used in East Asian cuisine and has a long history in traditional East Asian medical systems.

What does Lion's Mane look like?

Instead of a cap and stem, it grows as a spherical cluster of white, dangling spines that loosely resembles a lion's mane. According to the Royal Botanic Gardens, Kew, these fruiting bodies can grow as single spheres or as large groups of clusters reaching up to 30 cm across. Both parts of its scientific name come from Latin words for hedgehog, a nod to all those spines.

Where does Lion's Mane grow?

Kew describes Lion's Mane as a saprotroph, an organism that feeds on dead organic material. It grows mainly on dead or wounded trees in forests across North America, Europe and Asia, and is especially common on ash, beech, maple and oak.

What does Lion's Mane taste like?

Kew describes it as having a meaty texture and a mild natural flavor, which is why cooks add it to dishes such as stir-fries and stews.

What is Lion's Mane used for?

Lion's Mane is used in two quite different ways:

• As food. The fresh mushroom can be eaten raw, cooked or dried, and it is also used in tea.
• As a supplement ingredient. Lion's Mane is sold as capsules, powders, liquid extracts, gummies and drink mixes, and it appears in blends with other ingredients. It's often marketed for focus. WebMD's supplement overview notes that it is commonly used for many reasons, although its benefits are not well defined.

Supplements can be made from two parts of the fungus:

• the fruiting body, which is the visible mushroom, or
• the mycelium, the root-like network it grows from.

The two are not identical, so it is worth knowing which one a product uses.

What's in Lion's Mane?

Memorial Sloan Kettering lists several groups of naturally occurring compounds that researchers have found in Lion's Mane fruiting bodies and mycelia, including:

• polysaccharides, such as the beta-glucans common in mushrooms;
• hericenones and erinacines, two families of compounds that researchers studying Lion's Mane often focus on;
• phenolic acids, sterols and lactones.

These compounds are why researchers are interested in Lion's Mane, and why extracts are often described by how much of a particular compound they contain.

What does the research say?

This is where it pays to be careful, because online claims run far ahead of the evidence.

Most of the research so far is preclinical, meaning lab and animal studies. Those results are interesting to scientists, but they don't tell you what will happen when a person eats the mushroom or takes a supplement.

Human studies are few and mostly small. One of the better-designed recent examples is a 2023 pilot study from Northumbria University, published in Nutrients. Forty-one healthy adults aged 18 to 45 took either 1.8 g of Lion's Mane or a placebo:

• Sixty minutes after a single dose, the Lion's Mane group was faster on one attention task (the Stroop task).
• After 28 days, there was a trend toward lower self-reported stress, but it did not quite reach statistical significance.
• The researchers also reported null and some negative findings, and concluded that the results should be interpreted with caution because the sample was small.

In other words: early, mixed and promising enough to study further, but not settled. Be skeptical of any product that tells you Lion's Mane is "proven" to do something specific.

How much Lion's Mane per day, and how long does it take?

These are two of the most searched questions about Lion's Mane, and the honest answer to both is that there isn't a settled one. Lion's Mane isn't a nutrient with an official recommended daily amount, and studies have used different amounts, preparations and timeframes. If you use a Lion's Mane product, follow the suggested use on its label and ask your healthcare provider whether it's right for you.

Lion's Mane side effects and safety

Lion's Mane eaten as food is generally considered safe. Supplements are more concentrated than the mushroom you'd cook with, which is why Memorial Sloan Kettering recommends talking with your healthcare provider before taking them. Side effects reported in one clinical study included abdominal discomfort, nausea and skin rash. WebMD's overview adds that Lion's Mane seems to be well tolerated, but there isn't enough research to know what side effects it may cause, and that it's not known how it could affect pregnancy or whether it passes into breast milk.

Skip Lion's Mane, or ask your provider first, if you are pregnant or nursing, take medication, have a mushroom allergy, or are thinking of giving it to a child.

It's also worth knowing how supplements are regulated in the U.S. The NIH Office of Dietary Supplements explains that the FDA does not determine whether dietary supplements are effective before they are marketed. Companies are responsible for having evidence that their products are safe and that their claims are truthful.

Lion's Mane vs. L-theanine

The two often appear side by side, but they are very different things. Lion's Mane is a mushroom. L-theanine is an amino acid found naturally in tea leaves. Some products, including MyCellIQ, combine them. If you're comparing products, check the amount of each per serving rather than just the ingredient names. For more on how these ingredients show up in caffeine-free routines, see our guide to caffeine alternatives for focus.

How to read a Lion's Mane label

Because Lion's Mane products vary so much, the label matters more than the marketing. Look for:

1. The species name. Hericium erinaceus.
2. The part used. Fruiting body, mycelium, or both.
3. The amount in milligrams per serving, and how many servings are suggested per day. "Proprietary blend" without amounts tells you very little.
4. What an extract ratio means. A "10:1 extract" usually means 10 parts of dried mushroom went into 1 part of extract. A ratio says nothing about which compounds ended up in the extract, so a stated beta-glucan percentage is more informative.
5. Third-party testing. The NIH Office of Dietary Supplements notes that independent organizations such as U.S. Pharmacopeia, NSF International and ConsumerLab.com test supplements for identity and contaminants. Their seals don't guarantee that a product is safe or effective, but they do confirm what's in the package.
6. Caffeine. Many "mushroom coffee" products contain real coffee. If you want to avoid caffeine, check for a stated caffeine amount.

Why Lion's Mane is in MyCellIQ

We built MyCellIQ around Lion's Mane because people are interested in it as a caffeine-free ingredient, and because a gum is an easy way to make it part of the moment you sit down to work. (Curious how gum fits into all this? Read our guide to focus gum.)

Each 2.5 g piece contains 125 mg of Lion's Mane fruiting body extract, an ingredient chosen to support focus*. It also contains L-theanine, which supports calm focus*; saffron; and niacinamide and vitamin B12, which support normal energy metabolism*. There is no caffeine in it. Suggested use is 1 piece as needed, up to 4 pieces per day. (This is the target formula. The final label is confirmed before shipping.)

To be clear about the evidence: MyCellIQ has not been tested in its own clinical studies, and the Northumbria results above don't carry over to it. That study used 1.8 g of Lion's Mane a day. One piece of MyCellIQ has 125 mg, and even the maximum suggested use of 4 pieces a day adds up to 500 mg, well under a third of the study amount, in a different product. We'd rather tell you that plainly than borrow results from research on something else.

MyCellIQ is in development, with the first batch targeted to ship in Q1 2027. You can reserve a founding preorder for a $2 refundable deposit, join the waitlist to hear when it launches, or see the full product page.

The short version

• Lion's Mane (Hericium erinaceus) is an edible mushroom with white, shaggy spines, a meaty texture and a mild flavor.
• It's used in cooking and as a supplement ingredient. Supplements may use the fruiting body, the mycelium or both.
• Human research is early and small, with no settled daily amount or timeline. Be skeptical of bold claims.
• Read labels for species, part used, milligrams per serving, caffeine and testing.
• Talk with your healthcare provider before starting any supplement.

Sources

• Memorial Sloan Kettering Cancer Center, About Herbs. Lion's Mane Mushroom
• Royal Botanic Gardens, Kew. Lion's mane mushroom: King of the jungle?
• WebMD. Lion's Mane Mushroom: Overview, Uses, Side Effects, Precautions
• 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. PMC10675414
• BBC Good Food. Lion's mane benefits
• NIH Office of Dietary Supplements. Dietary Supplements: What You Need to Know
• U.S. Food and Drug Administration. Dietary Supplements