Reishi

Ganoderma lucidum / G. lingzhi

Family: Ganodermataceae Part used: Fruiting body; mycelium; spore powder (distinct products)

Key Compounds

• Ganoderic acid A
• Ganoderic acid B
• Ganoderic acid C
• Ganoderic acid D
• Beta-1,3-D-glucan
• Beta-1,6-D-glucan
• Lucidenic acids
• Ganoderenic acids
• Ergosterol
• Ganodermin

Traditional Use

• Traditional tonic use in Chinese medicine (historical record, Shennong Bencao Jing)
• Imperial symbol of divine favour and longevity (historical record)
• Long-term tonic decoction in Traditional Chinese Medicine (historical record)
• Supplement use in modern Japanese health practice

Reishi is not a plant. Fungi are more closely related to animals than to trees, which means the mushroom that Chinese emperors used as their symbol of divine immortality is biologically closer to you than it is to the oak tree it grows on. This has not been widely advertised as a selling point.

Meet the fungus

Ganoderma grows as a bracket from dead or dying hardwood — it does not grow in soil. No gills; the underside is white to cream pores. The cap is fan-shaped to kidney-shaped, up to 30 cm across, with a surface that looks lacquered: shiny, varnished, in concentric rings of reddish-brown fading to orange and cream at the margin. Hard, woody, cork-like. It is not a culinary mushroom — not because it’s toxic, but because it tastes extremely bitter and has the texture of something you would use to sand furniture.

The species sold as Reishi worldwide has been called Ganoderma lucidum for as long as anyone has been selling it. In 2012, taxonomists formally distinguished the East Asian medicinal species as G. lingzhi — a separate species from the European G. lucidum. The research done under the G. lucidum name for the previous fifty years may have involved multiple distinct species. Most commercial products still say G. lucidum. The taxonomy caught up with the market. The market has not rushed to update its labels.

It releases spores in large quantities — enough to coat nearby surfaces in rust-brown powder. The same mushroom produces three commercially distinct products: fruiting body, mycelium, and spore powder. All three are sold as “Reishi.” They contain different things and the difference matters. The packaging rarely explains this.

2,000 years of being the most important mushroom

The Shennong Bencao Jing (神農本草経) — the foundational text of Chinese herbal medicine, compiled in the Han dynasty from older tradition — ranks substances in three grades. Top grade: taken long-term with no toxicity, prolongs life. Lingzhi is top grade. In a document that classifies everything in Chinese pharmacopeia, this is the best available category. Reishi did not end up in second.

Chinese imperial culture took this further. Wild Reishi was extraordinarily rare — finding a specimen in the forest was taken as a supernatural portent of good fortune. Officials had careers built on presenting wild specimens to the court. Emperors received them as precious gifts. The mushroom appeared on imperial robes, furniture, ceramics, and paintings for two thousand years. The ruyi sceptre — the object of imperial authority carried by officials and gifted by emperors, meaning “as you wish” — has a head carved in the shape of a Reishi cap. The shape of divine authority was chosen to be a fungus that grows on rotting wood.

There was one problem with being the most symbolically important mushroom in Chinese history: almost nobody could actually find one. Wild Reishi is genuinely rare. The gap between the symbolic weight and the actual supply persisted for centuries. This ended when Shigeaki Mori (森重明), a Japanese mycologist, developed reliable commercial cultivation on sawdust substrate in the 1970s–1980s. Reishi went from supernatural rarity to health food store staple in roughly one decade. The symbolism remained. The rarity did not.

The chemistry that surprised everyone

Reishi’s active chemistry exists in two completely separate fractions that require different solvents to extract. This is not a minor distinction — it means that extraction method determines what’s actually in the product, and most labels don’t tell you which method was used.

Triterpenoids (ganoderic acids and related compounds): over 300 distinct compounds, found almost exclusively in the fruiting body, dissolving in ethanol but not water. They are intensely bitter. The bitterness is the triterpenoids — this is not a metaphor. A Reishi extract that doesn’t taste bitter is almost certainly low in triterpenoids. Mild-tasting or pleasant Reishi products are informing you of their composition even when the label isn’t.

Beta-glucans: polysaccharides that dissolve in hot water and are found in both fruiting body and mycelium. Traditional decoction — boiling Reishi slices for hours — extracts primarily this fraction. Beta-glucans are also found in oats, barley, and baker’s yeast; the Ganoderma versions have distinct structural characteristics. The traditional method predates the chemistry by two millennia and extracts the right fraction for hot water anyway. It did not need to know this.

Dual extraction uses both hot water and ethanol sequentially. It gets both fractions. High-quality supplements specify it. Products that don’t specify almost certainly aren’t dual extracted.

Then there is the grain problem. Mycelium is cheaper to produce than fruiting bodies — it grows on grain substrate (oats, rice, wheat bran). When mycelium products are independently tested, many contain more starch from the grain than Ganoderma beta-glucans. A product can accurately say “contains Reishi mushroom,” contain essentially no ganoderic acids, and have polysaccharide content that is mostly cereal starch. “Polysaccharide %” on a Reishi label is not useful because starch counts as polysaccharide. “Beta-glucan %” is specific. The label will tell you which number they chose to print.

What people actually do with it

Take as a supplement: Fruiting body extract, dual extracted, with a stated beta-glucan percentage. Taste it — noticeably bitter means triterpenoids are present. Mild means they probably aren’t. The taste test costs nothing and the label cannot lie about bitterness.

Drink it as a decoction: Simmer dried slices in water for 30–60 minutes. The water turns deep reddish-brown. Intensely bitter. Hot water extracts beta-glucans efficiently and some lighter triterpenoids. This is the preparation method Traditional Chinese Medicine has used for two thousand years.

Functional mushroom coffee: Low-dose Reishi combined with coffee, marketed as a wellness upgrade. Very popular. The Reishi dose in most products of this type is far below what any traditional use would consider meaningful. The coffee is almost certainly doing more.

Cracked cell wall spore powder: Collected from the spore clouds of mature fruiting bodies, mechanically processed. High triterpenoid content, expensive. A third distinct product category from the same mushroom — different chemistry profile, different price point.

Grow it yourself: Pre-inoculated sawdust blocks, 85–95% humidity, 24–28°C. Grow kits are available in Japan at garden centres and online. The mushroom that was once a supernatural rarity takes three to four months at room temperature and does not hurry.

Could you grow this yourself?

Yes — Reishi is one of the more accessible medicinal fungi for home cultivation. It grows on hardwood sawdust blocks, fruiting at 24–28°C with 85–95% relative humidity. Pre-inoculated blocks are sold in Japan at garden centres and online — you provide the tent, the warmth, and the patience.

The fruiting bodies take 3–4 months from inoculation. They first appear as white button-like protrusions, developing through an antler stage into the full fan-shaped cap. The shiny lacquered surface develops only in adequate humidity — a dry environment produces a dull, pale cap that looks nothing like the classic image and doesn’t photograph well.

Japan has commercial cultivation primarily in Nagano Prefecture. Most supplement-grade Reishi sold in Japan is cultivated. The wild harvest that once made finding a specimen a supernatural event is now a legacy category.

In Japan

Reishi has existed in Japan for approximately 1,400 years and occupies two completely different positions simultaneously: a classical symbol of divine longevity embedded in art and culture, and a commonplace supplement available at every chain pharmacy. The mushroom has not been asked to choose.

The symbolic heritage runs deep. 霊芝 appears in Japanese family crests (kamon), lacquerware, Buddhist temple imagery, and traditional decorative arts. The association with longevity and divine favour came with Buddhist transmission from China and became genuinely Japanese over centuries. It belongs to the culture in the way things do after 1,400 years.

The modern supplement market arrived in the 1980s following the cultivation breakthrough. Reishi is now one of the most name-recognised supplements in Japan — unlike most Western-origin supplements, which require explanation, 霊芝 is already in the cultural vocabulary. Available at Matsumoto Kiyoshi, Ainz & Tulpe, major health food chains, Amazon Japan, iHerb Japan. Major Japanese producers: Yamamoto Kanpo (山本漢方), DHC, Fancl.

Grow kits for home cultivation are sold at garden centres and home goods stores. The mushroom that appeared on imperial robes is now a ¥2,000 grow kit shipped in two days. This is not something anyone in the Han dynasty predicted.

Things you’re probably wondering

What is Reishi mushroom good for? Reishi (霊芝) has been used as a long-term tonic in Traditional Chinese Medicine for over 2,000 years, documented in the Shennong Bencao Jing as a top-grade herb. It contains triterpenoids (ganoderic acids) and beta-glucan polysaccharides. Traditional use is historical record, not medical advice.

What is the difference between Reishi fruiting body and mycelium? Fruiting body contains both triterpenoids and beta-glucans. Mycelium contains primarily beta-glucans and typically far fewer triterpenoids. Many mycelium products grown on grain substrate contain more starch than Ganoderma compounds when independently tested. Fruiting body extract is generally considered higher quality.

How do I know if my Reishi supplement is good quality? Fruiting body source specified. Dual extraction (hot water + ethanol) stated. Beta-glucan % on the label (not just “polysaccharide %”). Noticeably bitter taste. Species specified. Products missing these details have uncertain composition.

Where to buy Reishi in Japan? Matsumoto Kiyoshi, Ainz & Tulpe, health food chains, Amazon Japan, iHerb Japan. Growing kits at garden centres. Major Japanese brands: Yamamoto Kanpo, DHC, Fancl.

Can you grow Reishi at home in Japan? Yes — pre-inoculated sawdust blocks at 85–95% humidity, 24–28°C, 3–4 months. Practical. Kits available online and at garden centres.

Botanical details

The full compound list

Triterpenoids:

• Ganoderic acids A, B, C, D, G, H, I, J, K, M, R, S, T, Y (300+ identified)
• Ganoderenic acids
• Lucidenic acids
• Lanostane-type sterols

Polysaccharides:

• Beta-1,3-D-glucan
• Beta-1,6-D-glucan
• Proteoglycans

Proteins and sterols:

• Ganodermin (antifungal protein)
• Ergosterol (vitamin D2 precursor)

See Also

• Lion’s Mane (Hericium erinaceus) — medicinal fungus, distinct chemistry (hericenones, erinacines)
• Turkey Tail (Trametes versicolor) — bracket fungus, polysaccharide-K research
• Shiitake (Lentinula edodes) — culinary and medicinal; lentinan (beta-glucan)

References

• Shennong Bencao Jing (神農本草経, Han dynasty) — top-grade classification
• Bencao Gangmu (本草綱目, Li Shizhen, 1596) — six-colour lingzhi classification
• Wu SH et al. “Ganoderma species clarification.” Fungal Diversity 2012
• Wachtel-Galor S et al. “Ganoderma lucidum (Lingzhi or Reishi).” Herbal Medicine: Biomolecular and Clinical Aspects. CRC Press, 2011
• Stamets P. Mycelium Running. Ten Speed Press, 2005