Lion's Mane and the BDNF Question: What Two New Reviews Actually Found

If you’ve spent any time around functional mushrooms, you’ve seen the pitch. Lion’s mane “grows new brain cells.” Lion’s mane “boosts BDNF.” Lion’s mane is “nootropic.”

I talk about BDNF a lot. Brain-derived neurotrophic factor is one of the proteins tied to the brain’s ability to change and rewire itself, what scientists call plasticity. In plain terms, it’s linked to the brain’s capacity to form new patterns instead of repeating old ones. So when a mushroom gets marketed as a BDNF booster, I want to know what’s really under the hood.

Two reviews came out in the last two months that do exactly that kind of digging. Here’s what they found.

Review #1: healthy adults, and an honest “not yet”

On August 26, a team of Polish clinicians published a narrative review of lion’s mane (Hericium erinaceus) and cognitive enhancement in healthy young adults (Wardecki et al., 2026). They searched the human and mechanistic research available through June 2026.

What they found:

Only four studies looked directly at healthy young or college-age adults.
Some short-term studies reported changes on specific tests, like reaction times and attention tasks. But the findings weren’t consistent across studies or types of thinking, and some were only improvements over time within the lion’s mane group, not a clear win over placebo.
A four-week study in college-age adults found no cognitive benefit.
The reviewers note that studies in older adults or people with cognitive impairment reported more favorable results, but those concern impaired function, not boosting a healthy brain, and they weren’t the focus of this review.

And here’s the line that matters most for the BDNF pitch. The authors write that preclinical evidence most consistently supports activity related to nerve growth factor (NGF), “whereas evidence involving brain-derived neurotrophic factor remains less developed and largely experimental.”

Their bottom line: current evidence “does not support broad claims that lion’s mane improves cognition or memory in healthy young adults.”

Review #2: count the mice

On September 28, a systematic review and limited meta-analysis looked at lion’s mane and outcomes related to neurodegenerative disease (Ninyo et al., 2026).

The authors identified 23 studies that met their criteria. Now look at the breakdown:

12 were animal studies
8 were in vitro, meaning cells in a dish
3 were human clinical trials

In those lab and animal models, the authors describe consistent neuroprotective effects working through several pathways, including NGF and BDNF signaling, antioxidant defenses, and anti-inflammatory activity. That’s the mechanism story you see on the label.

But they’re clear about the limits. Human studies were limited and only suggested potential benefits. Heterogeneity was “substantial.” And the clinical efficacy in neurodegenerative disease “remains unconfirmed.”

That’s the rabbit hole in one picture. The mechanism is real enough to study, but it mostly lives in mice and petri dishes, not in people.

What about the newer human trial?

The most encouraging human data I found is an April 2026 preprint, which hasn’t been peer-reviewed (Daoust et al., medRxiv). It’s a randomized, double-blind, placebo-controlled trial of 109 adults aged 40 to 75 who reported cognitive concerns. After eight weeks of taking the study’s lion’s mane powder (fruiting body plus mycelium) or a placebo, the lion’s mane group showed significantly greater improvement on a visual attention and working memory task, and on self-rated sleep quality, restedness and mood.

Two honest notes. First, the authors themselves call the attention improvement modest. Second, the study was funded by M2 Ingredients, a mushroom ingredient company that also supplied the product, and two of the authors work there. The authors say the company’s authors could review but not change the analyses. That doesn’t make the result wrong. It does mean we wait for peer review and independent replication.

So what does this mean for a real person?

Here’s where I land. I don’t think the question is “does lion’s mane grow your brain?” The better question is: what are you building while your brain is able to change?

Even in the most hopeful version of this research, plasticity isn’t a direction. It’s an opening. An opening doesn’t choose the new pattern for you. You still have to choose a different response, and keep choosing it until it becomes the new habit. That’s reintegration, and no capsule does that part.

If you’re curious about functional mushrooms:

Read the label the way you’d read a study. Is it fruiting body, mycelium, or both? Is the extract standardized? Who tested it?
Watch for “BDNF booster” marketing. In humans, that claim is ahead of the evidence.
Talk with your clinician before adding any supplement, especially if you’re pregnant, nursing, managing a health condition, or taking medications.
Put your energy into the new habits: sleep, movement, people, and purpose.

Be Better. The opening is only half the story.

Sources

Wardecki SM et al. Hericium erinaceus and Cognitive Enhancement in Healthy Young Adults: A Narrative Review. International Journal of Innovative Technologies in Social Science, Aug 26, 2026. https://rspublisher.org/index.php/ijitss/article/view/6297
Ninyo MG, Zhang G, Zhou S. Neuroprotective Effects of Hericium erinaceus: Evidence from Experimental and Clinical Studies—A Systematic Review and Limited Meta-Analysis. Food as Medicine (Scilight Press), Sep 28, 2026. https://www.sciltp.com/journals/fm/articles/2609005202
Daoust J, Farrar S, et al. A randomized, double-blind, placebo-controlled study evaluating the impact of Hericium erinaceus (Lion’s Mane) on cognitive performance and subjective wellbeing. medRxiv preprint (not peer-reviewed), April 17, 2026. Funded by M2 Ingredients. https://www.medrxiv.org/content/10.64898/2026.04.13.26350781v1.full
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. Nutrients 2023;15(22):4842. https://doi.org/10.3390/nu15224842

Education only, not medical advice. Talk with a qualified clinician about your own health.