If you have spent time online lately, you’ve probably seen marketing for lion’s mane mushroom supplements with claims of health-boosting and disease-preventing properties. But does the science support these products and claims, or are they just another fad?
What actually are lion’s mane mushrooms?
Lion’s mane, scientifically Hericium erinaceus, are big, shaggy-looking mushrooms. They are edible, with a mildly sweet flavour and tender texture, and are used in gourmet cooking. They also have an extensive history as a traditional medicine, which has attracted the attention of Western science and modern marketers.
There is a lot of research on lion’s mane – they've been noted in at least 410 research papers in the last 10 years.
At first, this sounds like a lot. However, only about a quarter of these studies have involved humans. The others used model systems like rodents or cell cultures (where extracts were applied directly to cells). Other mentions of Hericium erinaceus have been in review articles summarising ideas from other research projects.
In total, there have been just seven human clinical trials, the gold-standard study type for interventions. So, which, if any, of the claims found across the internet are backed by science?
Can Lion's mane mushrooms better your health?
Heart health
Around one in three adults in the UK have high blood pressure, and up to half have raised cholesterol. Both increase risks of cardiovascular disease, including stroke and heart attacks – some of the most common causes of death.
Lion’s manes extract has been shown to improve blood lipid levels in obese rodents and reduce oxidation in cell culture. Oxidation of lipids in the bloodstream contributes to hardening of the arteries. Lion’s mane also includes a compound, Hericenone B, which has been researched for its potential as an anti-clotting agent.
Diabetes
Diabetes impairs the regulation of blood sugar levels. The number of young people diagnosed with diabetes has been rising in recent years, and high blood sugar in the long term can damage vision, kidneys and nerves.
Studies have shown lion’s mane controls blood sugar in rodents. Cell studies have also shown that some parts of the lion’s mane inhibit an enzyme that breaks down sugars, so some researchers have hypothesised that this could reduce blood sugar. But, this hasn’t been demonstrated in any actual humans, let alone people with diabetes.
Cancer protection
Many chemotherapies have been developed from natural sources like bacteria and plants, so it makes sense to look for them in mushrooms too.
Multiple potential candidates that act on cancerous cells have been identified from lion’s mane. Some mouse studies have shown it can inhibit the growth of implanted tumours in the lungs and the colon. Extracts applied directly to cancer cells have reduced growth or killed cells from a variety of cancers, including liver, colon, stomach and blood cancers.
But inhibiting cancer cells in a test tube doesn’t translate into supplements doing the same thing. Cultures are simple systems compared to our bodies, and the doses used are typically high.
Killing or inhibiting cancer cells in the lab isn’t actually difficult; just adding water can slow their growth, for example. What is difficult is finding compounds that can get into the right cells without harming the rest, and that hasn’t been shown yet for any lion’s mane extract.
Mental health and cognition
Brain health isn’t just the absence of diseases like dementia or depression, it includes optimal cognition, such as executive function – mental skills such as memory, flexible thinking, and self-control. This is where some human study data on lion’s mane extracts are available.
Extracts applied directly to neuronal cells help them grow with less oxidation and inflammation, which can cause damage and are implicated in conditions like Alzheimer’s and dementia.
In mice, extracts have been shown to reduce plaques in the brain, a key feature of Alzheimer’s, and the mice given these extracts have been seen to perform better in memory tests.
Clinical trials of people with mild Alzheimer’s and with mild cognitive impairment found daily lion’s mane improved scores in cognitive tests. But, these studies were small (30-40 people), so we need to examine more people to know if this difference is true or just based on chance.
Similarly, small human trials have also shown lion’s mane might improve stress and mood in young adults and menopausal women. Mouse studies showing changes in behaviour also show changes in parts of the brain linked to emotion.
Ultimately, at the moment the evidence isn’t strong enough to recommend replacing medications or other treatments with supplements.
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Immunity and inflammation
Improving immunity and inflammation is a tricky claim. Both are necessary to fight infections and heal wounds, but too much or misdirected responses can cause harm and chronic conditions like diabetes, cancers, cardiovascular diseases and autoimmune diseases. Boosting immunity isn’t a straightforward benefit.
Cell culture testing shows that lion’s mane compounds can have antioxidant and anti-inflammatory effects – but this is true for all fruits, vegetables and whole grains. When tested against other mushrooms, lion’s mane didn’t have the most antioxidants (reishi mushrooms were the winners).
In cell and animal models, lion’s mane extracts increase signalling in immunity pathways, but it isn’t clear if this has any benefits. When mice were given a lethal dose of bacteria, lion’s mane kept them alive longer and with stronger immune responses. But more isn’t necessarily better, as harm can occur due to immune responses.
Supporting gastrointestinal health
Poor gastrointestinal health and symptoms can impact quality of life. The gut is also generally linked to health through its effects on gut microbes.
Lion’s mane limits the growth of Helicobacter pylori, the bacteria that causes stomach ulcers in cell and animal models. In animal models of alcohol-induced ulcers, inflammatory bowel disease and colitis lion’s mane helped prevent onset and reduce severity, possibly through changes in the gut microbes. But, these effects are not demonstrated in humans.
A small study of people with ulcerative colitis found lion’s mane supplementation, reduced symptoms. However, a similar study of people with Crohn's disease found no benefit.
So, can lion’s mane mushroom supplements help humans?
Most available products focus on extracts, capsules and powders, rather than whole mushrooms. That’s because they are easier to study, particularly when the aim is to develop new medications, not dietary recommendations.
Lion’s mane products also vary. Water-based extract contents differ from oil or alcohol tinctures, for example. Extracts are more concentrated, but powders (and pills made from powders) will contain a more diverse variety of compounds.
This variety and the nature of the data means it’s difficult to determine the recommended doses. It’s hard to scale from cell culture studies to ingestible amounts as cell culture studies apply concentrated forms directly and don’t account for digestion or metabolism.
Animal studies typically use 2-10mg of extract per kg of body weight – for a 70kg human this is 140-700mg. But mice aren’t humans, so it’s not that simple of an equation. In the human studies that have been done, doses range from 350mg to 5 grams.
Are there any side effects?
Lion’s mane is generally well tolerated but may cause gastrointestinal upset, nausea or skin rashes, and it can cause allergies and breathing difficulties. Care may be needed if taking other medications, as they may interact or enhance effects, even if supplements seem natural, so it’s always best to check with your doctor.
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