Tremella

What it is

Tremella fuciformis is a white, frilly jelly fungus that grows on wood. In Asia it has been used for centuries as an edible and medicinal mushroom, usually dried and soaked before cooking. For cultivation it needs a partner fungus that breaks down the wood for it. In the German guidelines for edible mushrooms, it is on the list of common species as Silberohr.

As a dietary supplement, powder or extract from the fruiting body is usually sold, often under names such as snow mushroom or as a beauty mushroom. In cosmetics, Tremella extract is found in creams and serums. These are two different applications with different data.

New are products with isolated components, such as purified chondroitin sulfate from the fruiting body, which is planned for dietary supplements at up to 500 mg per day. Such isolates are legally something different from mushroom powder and require their own authorization in the EU.

How it is supposed to work

The most important constituent is Tremella polysaccharides. Unlike the beta-glucans from shiitake or oats, this is an acidic heteropolysaccharide built mainly from mannose, xylose and glucuronic acid. These sugar chains bind a lot of water and form gels. This is the origin of the idea of plant-based hyaluronic acid.

On the skin this is plausible, because a moisture film acts directly there. When swallowed, the route is different. The large sugar chains are not transported unchanged to the skin, but end up in the large intestine, where they are fermented by bacteria. A 2026 review therefore describes the plausible route via the gut flora: fermentation, short-chain fatty acids, less inflammation in the body and, through this, perhaps a better skin barrier. In mice with an atopic dermatitis model, Tremella polysaccharides even worked better when swallowed than when applied topically, accompanied by more regulatory T cells and an altered gut flora. In cell and animal studies, the polysaccharides also show antioxidant, blood sugar-lowering and blood lipid-lowering effects. Unlike shiitake or oyster mushrooms, however, Tremella provides hardly any ergothioneine, only traces in the range of micrograms per gram.

What users are looking for

Most people reach for Tremella for plumper, better-hydrated skin, often together with collagen or hyaluronic acid. Some use it for memory or simply as a traditional food. Many report softer, less dry skin after a few weeks. These are user reports that should be taken seriously, but no controlled study has confirmed them so far.

What the studies show

The memory study

75 adults with subjective memory complaints received 600 mg or 1,200 mg of Tremella per day or placebo for eight weeks, 30 each in the Tremella groups and 15 in the placebo group. Complaints, short-term memory and executive functions improved more than with placebo. Brain imaging showed volume differences in individual regions, but this was an exploratory additional analysis.

The prediabetes study

56 overweight adults with prediabetes drank a Tremella beverage or placebo for twelve weeks, 28 per group. In the Tremella group, HbA1c and waist circumference decreased slightly. However, the authors only compared before and after within the groups; they do not report a direct comparison with placebo. The study was funded by a food company.

The atopic dermatitis mouse

Mice with an artificially induced atopic dermatitis-like inflammation received Tremella polysaccharides applied topically or in their feed. Both routes reduced water loss, skin thickening and swelling; swallowed, they worked better. This is an animal model and shows a possible route, not an effect in humans.

Where the data stop

For the main promise, the skin from within, there is not a single human study. A 2026 review notes that oral hyaluronic acid has been tested on human skin, whereas Tremella polysaccharides have not. The evidence comes from animal experiments, cell culture and topical cosmetics. I did not find the widespread advertising claim that Tremella binds many times its weight in water in any primary study. And even high water binding in a glass says nothing about what reaches the skin after swallowing. Some manufacturers speak of mushroom-based hyaluronic acid; so far this has only been studied in a laboratory model.

The other findings are narrow too. The memory study is small, its primary endpoint is a questionnaire, and it has not been replicated. A second study tested a combination drink of fish roe, Tremella and yeast, whose effect cannot be attributed to the mushroom. The blood sugar data are exploratory. There are no long-term data and no studies on longevity endpoints.

Status, approval and legal

According to the EU Novel Food Catalogue, the fruiting body of Tremella fuciformis is not considered novel; it is an ordinary food and may be sold as powder or extract in dietary supplements. In Germany, Belgium and Spain it is on national positive lists for edible mushrooms. The mycelium, that is, the fungal network, is a different matter: it is considered a novel food without authorization. This also applies to isolated chondroitin sulfate from Tremella, which was classified as novel in 2025. There is no authorized EU health claim for Tremella, so advertising skin or memory effects is not permitted for foods. Tremella is not on the WADA Prohibited List 2026.

Safety

In the studies over eight to twelve weeks, side effects did not occur more often than with placebo. However, systematic safety data and long-term studies are lacking, and I found no case reports of harm from Tremella products. A real risk concerns the kitchen: fresh mushrooms or mushrooms soaked for too long can be colonized by the bacterium Burkholderia gladioli. Its toxin-producing variant generates bongkrekic acid, for which there is no antidote. In Shanghai, 16.6 percent of fresh Tremella samples carried the bacterium, but the toxin-producing variant was found there only in dried wood ear (mu-err). A report by the Chinese Center for Disease Control and Prevention advises against eating mushrooms soaked for 24 hours or longer. Interactions with medicines have not been studied in humans. Because animal data point to a lowering of blood sugar, anyone taking diabetes medication should discuss this with a doctor. There are no data for pregnancy and breastfeeding, and no official maximum amounts either.

Sources

• Ban et al., J Med Food 2018 – Tremella in subjective cognitive impairment
• Gitsomboon et al., BMC Nutr 2024 – Tremella drink in prediabetes
• Wang et al., Antioxidants 2026 – edible mushrooms and skin, evidence gaps
• Mineroff and Jagdeo, Arch Dermatol Res 2023 – Tremella and skin
• Xie et al., Front Pharmacol 2022 – Tremella polysaccharides in an atopic dermatitis mouse model
• Lourith et al., J Cosmet Dermatol 2021 – hand gel with Tremella extract
• Xiao et al., China CDC Wkly 2025 – Burkholderia gladioli in edible mushrooms
• Li et al., Front Nutr 2025 – review of Tremella polysaccharides
• European Commission – novel food consultation on chondroitin sulfate from Tremella fuciformis, 2025