The Fungus That can Cross the Blood Brain Barrier: Lion's Mane & the BBB
- Mar 22
- 3 min read
Updated: Mar 30
If you’ve spent any time in the wellness or "superfood" world lately, you’ve likely heard of Hericium erinaceusor, or, as it is more commonly known, the Lion’s Mane mushroom. It's not uncommon to see it almost worshiped by health gurus or those annoying ads that pop up while you're browsing, and it's often a major ingredient in many a mushroom supplement: but what really makes it so popular? After all, with all the hype this curious toothed fungus has been receiving, it's easy to dismiss it as yet another exaggerated health fad–but is it? Let's delve into some of the science behind it.
It's no secret that your brain is your most protected organ, which is why it's protected by a highly selective "filter" that prevents toxins and large pathogens in your blood from entering your brain tissue: the Blood Brain Barrier (BBB). It's a double-edged sword, though: while it keeps you safe, the BBB also makes it incredibly difficult for most medicines and supplements to actually get where they need to go. That's where our shaggy fungus comes in–Lion’s Mane bypasses this defense through two families of low-molecular-weight compounds.
Hericenones, aromatic compounds found primarily in the fruiting body.
Erinacines, chemical compounds concentrated in the mycelium, the mushroom's root-like network (see the post Fungal Biology)
Unlike many large-molecule proteins, these compounds are small enough to cross the BBB and stimulate the synthesis of two important neurotrophins (specialized proteins): Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF) directly within the brain. NGF is like a "fertilizer" for your neurons as it is aids in the survival, maintenance, and regeneration of nerve cells. As we age (or due to neurological stress), NGF levels can go down, leading to brain fog or cognitive decline.
Because the compounds in Lion's Mane can cross the BBB, they can stimulate your brain to produce its own NGF, which supports neuroplasticity, your brain’s ability to form new neural connections. Meanwhile, BDNF helps create new neurons from stem cells and strengthens the connections between neurons. However, large-scale confirmation between Lion's Mane and these benefits in humans is still an active area of research.
Here's some of the actual clinical evidence:
A. In a Japanese placebo-controlled trial (a clinical trial that compares a new treatment, in this case Lion's Mane, against an inactive substance) adults with mild cognitive impairment showed significant improvements in cognitive scores after 16 weeks of consistent intake. These benefits were tied to continued use, though–scores declined four weeks after supplementation ended. (https://pubmed.ncbi.nlm.nih.gov/18844328/#:~:text=A%20double%2Dblind%2C%20placebo%2Dcontrolled%20clinical%20trial%20examined%20the,three%20times%20a%20day%20for%2016%20weeks)
B. A study indicated that erinacines can reduce the buildup of amyloid-beta plaques, a primary biological marker of Alzheimer's disease. (https://pmc.ncbi.nlm.nih.gov/articles/PMC4924315/)
C. A 4-week trial involving 30 menopausal women found that those eating cookies containing Lion's Mane extract reported significantly lower levels of depression, anxiety, and "irritability" than the placebo (fake treatment) group. (https://pubmed.ncbi.nlm.nih.gov/20834180/)
There's currently no scientific evidence that proves Lion's Mane is a "fix" for all your neurological problems, but all of these studies really makes one wonder: is there such thing at all? I think it's safe to say for now that anyone promoting a "miracle-cure superfood" is best to be taken with a grain of salt. Instead, it's better to think of Lion's Mane and other inflated foods as a sort of "supplement" (not to replace your multivitamins, of course!) or, in general, just a healthy food.
Bibliography
Mori, Koichiro, et al. “Improving Effects of the Mushroom Yamabushitake (Hericium Erinaceus) on Mild Cognitive Impairment: A Double-Blind Placebo-Controlled Clinical Trial.” Phytotherapy Research, vol. 23, no. 3, Mar. 2009, pp. 367–372, pubmed.ncbi.nlm.nih.gov/18844328/, https://doi.org/10.1002/ptr.2634.
Tsai-Teng, Tzeng, et al. “Erinacine A-Enriched Hericium Erinaceus Mycelium Ameliorates Alzheimer’s Disease-Related Pathologies in APPswe/PS1dE9 Transgenic Mice.” Journal of Biomedical Science, vol. 23, no. 1, 27 June 2016, https://doi.org/10.1186/s12929-016-0266-z.
S.R, Venkat. “What Are the Health Benefits of Lion’s Mane Mushrooms?” WebMD, 1 Apr. 2024, www.webmd.com/diet/what-are-the-health-benefits-of-lions-mane-mushrooms.
Nagano, Mayumi, et al. “Reduction of Depression and Anxiety by 4 Weeks Hericium Erinaceus Intake.” Biomedical Research (Tokyo, Japan), vol. 31, no. 4, 2010, pp. 231–7, www.ncbi.nlm.nih.gov/pubmed/20834180, https://doi.org/10.2220/biomedres.31.231.
