Beta-Glucans, Adaptogens & Nootropics — The Science of Medicinal Fungi

Beta-Glucans — The Immune Modulators

Beta-glucans are polysaccharides found in the cell walls of fungi, bacteria, and some plants. They are the most studied and best-evidenced bioactive compounds in medicinal mushrooms. The beta-glucans in fungi — particularly the 1,3/1,6-beta-D-glucan structure — interact directly with receptors on immune cells including macrophages, natural killer cells, and dendritic cells.

The mechanism is immune modulation, not immune stimulation. This is an important distinction. Beta-glucans do not simply push immune activity higher — they help regulate and calibrate immune response. This is why they are studied in both cancer support (where enhanced immune surveillance matters) and autoimmune contexts (where dysregulated immune activity is the problem).

Best sources by species

Extraction note: Beta-glucans are water-soluble. A hot water extraction (tea or decoction) extracts them effectively. Alcohol extraction does not — alcohol is needed for the triterpenes in Reishi, not the beta-glucans. A dual extraction (hot water + alcohol) captures both compound classes.

NGF Compounds in Lion's Mane — The Nootropic Evidence

Lion's Mane (Hericium erinaceus) contains two classes of compounds unique to this species: hericenones (found in the fruiting body) and erinacines (found in the mycelium). Both have been shown to stimulate the synthesis of Nerve Growth Factor (NGF) — a protein essential for the growth, maintenance, and survival of neurons.

NGF cannot cross the blood-brain barrier directly. However, hericenones and erinacines are small enough molecules to cross it, then trigger NGF production inside the brain. This indirect mechanism is what makes Lion's Mane neurologically interesting in a way that most "brain supplements" simply are not.

What the human trials show

A double-blind placebo-controlled trial published in Phytotherapy Research found that adults with mild cognitive impairment who took 3 grams of Lion's Mane powder daily for 16 weeks showed significantly improved cognitive function scores compared to placebo — and that these improvements reversed when supplementation stopped. A 2023 study at the University of Queensland identified specific compounds in Lion's Mane that promoted neuron growth and memory formation in laboratory models.

The evidence is promising but still early for human applications. The animal and in vitro data is strong. The human trials are small. What can be said confidently: Lion's Mane appears neurologically active, the proposed mechanism is plausible and partially demonstrated, and no significant adverse effects have been recorded in trial doses.

Triterpenes in Reishi — The Adaptogen Chemistry

Reishi (Ganoderma lucidum) contains over 140 identified triterpenes — bitter-tasting compounds responsible for the mushroom's characteristic sharp flavour. The most studied are the ganoderic acids, which show anti-inflammatory, hepatoprotective (liver-protective), and anti-tumour properties in laboratory and animal studies.

Triterpenes are the primary reason Reishi is classified as an adaptogen — a substance that helps the body adapt to stress and normalise physiological functions. The evidence for adaptogenic effects is largely preclinical, but the anti-inflammatory mechanisms are well-characterised biochemically.

Triterpenes are alcohol-soluble, not water-soluble. A tea made from Reishi extracts beta-glucans but leaves most triterpenes behind. For full-spectrum Reishi extract, a dual extraction using both hot water and ethanol is required — hence why quality Reishi supplements specify "dual extract" on the label.

Ergothioneine — The Longevity Molecule

Ergothioneine is an amino acid that humans cannot synthesise — we must obtain it from diet. Mushrooms are the primary dietary source. It accumulates in tissues under oxidative stress — the brain, liver, kidneys, and lens of the eye — where it acts as a cytoprotective antioxidant.

Research from Penn State University found that people who eat more mushrooms have significantly higher ergothioneine levels, which correlate with markers of reduced oxidative stress. Epidemiological data from Singapore showed that higher mushroom consumption correlated with reduced risk of cognitive decline in a study of over 600 adults over 70.

All edible mushrooms contain ergothioneine. Oyster mushrooms and Shiitake contain particularly high concentrations relative to common vegetables. Cooking does not significantly degrade it — ergothioneine is heat-stable.

Cordycepin in Cordyceps — Energy and Performance

Cordyceps militaris (the cultivatable species, as opposed to the parasitic Ophiocordyceps sinensis) contains cordycepin (3'-deoxyadenosine), a compound that affects cellular energy systems via the adenosine pathway. It is studied for effects on ATP production, oxygen utilisation, and exercise performance.

A double-blind trial in older adults found that Cordyceps supplementation improved VO2 max (a measure of aerobic capacity) significantly compared to placebo over 12 weeks. Effects on younger trained athletes are less clear — baseline fitness matters. Cordyceps is one of the better-evidenced mushrooms for athletic performance claims.

Practical Guide — What to Take and How

Growing Your Own Medicinal Mushrooms

The most reliable way to get high-quality medicinal mushrooms is to grow them yourself. You control substrate, harvesting time, drying conditions, and storage. A home-grown, properly dried and stored oyster mushroom contains more ergothioneine than any capsule made from unknown myceliated grain.

For Reishi specifically — the species with the highest triterpene content — grow on hardwood, allow the cap to fully mature and develop a thick woody texture before harvesting, and dry at 45–50°C until fully desiccated. Use the dried Reishi for tea (hot water extraction) or make a dual extract: simmer in water for 2 hours, then add food-grade ethanol to the cooled liquid at 25–30% concentration.

Use our Grow Cycle Tracker to time your Reishi harvest for maximum triterpene development.