Can Lion’s Mane Improve Cognitive Function?

Lion’s mane is yet another contribution from East Asian traditions that has found its place in Western wellness culture. Today, it’s commonly described as a nootropic, and many supplement products associate it with benefits like sharper focus, better memory, or overall improvements in mental performance.

While lion’s mane can also be enjoyed as food (and yes, lion’s mane steaks can be surprisingly good), this article focuses on its use as a supplement, and looks at what PubMed has to say about the lion’s mane latte that promises a special brain boost.

What is lion’s mane?

It goes by many names: monkey head, bearded tooth, pom-pom mushroom, *Yamabushitake, ‘*mountain priest mushroom’ in Japanese.

Lion’s mane (Hericium erinaceus) is a white, shaggy mushroom that has long been consumed both as food and as a traditional tonic, primarily in China and Japan. In traditional Eastern medicine, it has been used to support digestion, nerves, and overall health. Today, its potential role in brain health is what draws the most attention.

Lion’s mane supplements are available in many forms, including capsules, powders, tinctures (or drops), and even tea and coffee blends.

What is cognitive function?

Cognitive function is a broad umbrella term for the mental processes that help us understand, navigate, and adapt to the world. It includes a wide range of mental tools, from basic ones like attention and working memory to more complex abilities such as learning, reasoning, and problem-solving.

For something so broad that there’s an entire field of cognitive neuroscience dedicated to it, it’s easy for the definition of cognitive function to get a bit murky. This is especially true given how many different ways there are to measure it. Some studies zoom in on specific abilities, like memory or attention, while others use broader screening tools that combine several tests to capture overall cognitive status.

How is lion's mane thought to work?

Most of what we know about how lion’s mane might affect the brain comes from preclinical research, meaning studies in cell cultures and animal models.

The main bioactive compounds involved are:

• Erinacines, found mainly in the mycelium (the root-like structure of the fungus)
• Hericenones, found primarily in the fruiting body (the visible, edible part of the mushroom)

Neuronal growth factors

One of the most discussed mechanisms behind lion’s mane’s potential cognitive effects is its influence on neuronal growth factors, particularly nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF).

In cell and animal studies, erinacines and hericenones have been shown to increase the production of these growth factors, often accompanied by improvements in learning or memory tasks. Neuronal growth factors help brain cells survive, repair themselves, and form new connections, processes that underlie brain plasticity and are central to learning and memory.

There is preliminary evidence suggesting that lion’s mane supplementation might increase BDNF levels in humans as well. But at this point, we don’t know how consistent this effect is, how strong it might be, or whether it meaningfully translates into better cognitive performance.

Anti-inflammatory and antioxidant effects

Preclinical studies also suggest lion’s mane may have anti-inflammatory and antioxidant properties. Chronic inflammation and oxidative stress can interfere with communication between neurons and have been linked to brain aging and cognitive decline. Reducing these processes could, in theory, help protect brain function over time and support cognitive health.

Altogether, this makes a biologically plausible case for how lion’s mane might support cognition, with rodent studies backing up that idea. Still, plausibility isn’t proof. What works in mice doesn’t always translate to humans, which is why clinical studies are essential.

Evidence from clinical trials

Human research on lion’s mane and cognition is still early and limited, and the existing studies are relatively small.

Potential benefits in older adults

So far, the most promising results come from older adults with impaired cognition.

• One of the earliest controlled trials, published in 2009, studied older adults with mild cognitive impairment. Participants who took lion’s mane daily for four months showed improvements in a cognitive screening score compared to placebo. While promising, it’s important to keep in mind that the study was small and relied on relatively coarse cognitive measures, so the results should be interpreted with caution.
• Another pilot trial in which people with early Alzheimer’s took lion’s mane for nearly a year also reported some benefits. While lion’s mane did not consistently outperform placebo across all cognitive tests, participants taking it tended to show slower decline or small improvements relative to their own baseline, particularly in measures related to daily functioning.

While age-related cognitive decline is much subtler than in disease, cognition does tend to get worse with age, so support may also be relevant for healthy older adults.

A recent clinical trial in 33 healthy adults over 50 reported improvements in information processing speed after two months of lion’s mane supplementation, while other cognitive measures showed no significant changes. While it would be ambitious to draw firm conclusions about overall cognitive improvement, the findings do hint at a small, subtle effect.

Taken together, while it’s too early to draw any prescriptive conclusions from so few studies, the existing evidence offers a signal that long-term lion’s mane supplementation may help support cognitive function in older adults, particularly those experiencing decline beyond what’s considered healthy aging.

Little support for benefits in healthy young adults

While for older adults lion’s mane is most relevant as long-term support to keep the brain as healthy and well-working as possible, its appeal for younger people is often about boosting performance.

Here, the evidence is much less convincing. One small study in 24 healthy college athletes and a larger trial in 41 healthy young participants found no improvements in cognitive function compared to placebo after a month of daily supplementation. The latter also looked at short-term effects and found no differences in overall cognition one hour after supplementation, although the supplement group performed slightly better on a specific mental processing task.

Similarly, another small trial found no improvement in global cognition 90 minutes after taking lion’s mane, but did observe improvement in a specific motor task.

What these isolated findings mean is still unclear. The evidence so far suggests that in healthy young brains, lion’s mane has not been shown to produce measurable cognitive benefits and does not currently live up to the idea of a meaningful brain booster.

Does lion’s mane help ADHD?

This is a popular topic online, but the evidence simply isn’t there.

Despite frequent claims that lion’s mane can improve attention or executive function in ADHD, there are no clinical trials testing lion’s mane in people diagnosed with ADHD. Existing claims are based on animal studies, mechanistic theories, or extrapolation from cognitive impairment research.

At this point, there is no scientific basis to support lion’s mane as a treatment for ADHD.

Why are these findings hard to interpret?

Does this mean lion's mane has no potential? Not necessarily. For now, there just isn’t a strong enough evidence base to support confident recommendations.

Most of the available studies are small pilot trials, and the effects observed so far tend to be on the modest side. On top of that, studies vary widely in the form of lion’s mane used, the doses given, and the cognitive tests chosen, which makes results hard to compare or combine.

Some studies also involve industry participation. That doesn’t automatically invalidate the findings, but it’s important to keep in mind, as well as appreciate independent replication.

At this stage, the research is still too early and too limited to support strong, clear guidance, and it’s best viewed as an early signal rather than anything close to a definitive answer.

Is it safe to use?

Lion’s mane is generally considered safe and well-tolerated, and it has a long history of use. In clinical studies, reported side effects have been rare and mostly mild. A few studies have noted digestive discomfort or allergic reactions, so consult a healthcare professional if you have concerns.

If you do consider taking a supplement, keep in mind that quality can vary widely. Formulations are not yet standardized, and we don’t really know which form or dose, if any, is optimal. Looking for transparent sourcing and avoiding excessive doses may be a sensible approach.

As always, it’s a good idea to discuss supplements with a healthcare professional, especially if you have underlying conditions or take medications.

Bottom line

Lion’s mane is an interesting candidate for further research, especially in the context of cognitive decline. For now, though, it’s best viewed as a potential supportive tool, not a proven nootropic, as it lacks solid evidence to support common claims around boosting focus, productivity, or ADHD symptoms.

As with many supplements, science is still evolving. We not only need larger, long-term studies, but also standardized formulations and doses.

And as for the lion’s mane latte, at least for now, a PubMed-informed take would say the most likely brain boost in that cup is still the caffeine.