How To Spot A Good Quality Mushroom Supplement

You tell whether a mushroom supplement is good quality from four things on the label: which part of the fungus was used, whether a beta-glucan figure is given, what the extraction ratio is measured against, and whether the finished batch has been tested. If a product will not answer those four, the price tells you nothing and neither does the packaging.

This matters more here than in most supplement categories, because the gap between what the label says and what is in the tub has been measured by analytical chemists more than once. The results were not close.

The evidence that labels and contents come apart

Wu and colleagues, in Scientific Reports in 2017, bought 19 batches of Ganoderma lucidum supplements from US online retailers including Amazon and eBay and compared them with an authenticated fruiting body. They looked for the branched 1,3-beta-D-glucan that characterises the mushroom, and for starch-like polysaccharides that would indicate filler. The beta-glucan was detectable in 5 of the 19 products. Starch-like polysaccharide was present in 13 of the 19. The measured ingredients matched the label in 5 of 19 samples, and the authors concluded that quality consistency in that market was poor.

Windsor and colleagues, in the International Journal of Molecular Sciences in 2025, ran the same exercise on chaga. Authenticated whole chaga contained roughly 5.7 to 11.9 per cent beta-glucans and under 2 per cent alpha-glucans. Fermented grain products contained 1.0 to 6.9 per cent beta-glucans and 33.1 to 68.4 per cent alpha-glucans, and an iodine starch test came back positive on every one of them and negative on the authentic material. The authors read the beta-glucan in those products as cereal beta-glucan and cellulose from the substrate, not fungal biomass.

Neither study names brands and neither surveys the UK market. Both are small snapshots, and the chaga work covers roughly five commercial products. But two laboratories, eight years apart, on two fungi, found the same pattern: grain where the label implied mushroom.

Question one: which part of the fungus

A mushroom has two relevant parts. The fruiting body is the thing you would recognise as a mushroom. The mycelium is the root-like network it grows from. Both are real fungal material.

The problem is one production route: mycelium grown on a bed of rice, oats or sorghum, then dried and milled with the grain still attached, because separating them at scale is impractical. What comes out is a mycelium-and-grain powder, and if the label says only "mushroom" and gives a weight, that weight may be mostly substrate. The alpha-glucan figures in the 2025 chaga paper are what that looks like in a laboratory: 33.1 to 68.4 per cent starch-type glucan against under 2 per cent in the authentic material.

The useful label question is not "mushroom or not" but "fruiting body, mycelium, or mycelium on grain, and does it say".

Question two: beta-glucan, not polysaccharide

Beta-glucans are the structural carbohydrates in fungal cell walls, and they are the number the better manufacturers measure. "Polysaccharide" is a far wider category that includes starch from grain. A label reporting a high polysaccharide percentage and no beta-glucan percentage has told you something a bag of rice flour could also tell you.

Question three: what 10:1 actually means

An extraction ratio is a weight relationship. A 10:1 extract means ten kilograms of starting material produced one kilogram of extract. It describes process yield, not what ended up concentrated, and it is only as meaningful as the starting material.

Ratios sit in a convenient blind spot: nobody has to say what was being concentrated, and nobody has to pair the ratio with a content figure. A 10:1 claim alongside a measured beta-glucan percentage is informative. On its own it is a number with no denominator you can check. The general guide to reading a supplement label covers the rest of the panel.

Question four: has the batch been tested

Fungi take up what is in their growing medium, so contaminant testing is a reasonable thing to ask about. The questions are narrow and answerable: which contaminants, at what stage, every batch or periodically, and will they show you a result. Cacao-based products carry a related question, covered in the page on lead and cadmium in chocolate.

How to tell if a mushroom supplement is good quality: a reading order

Work through the label in this order and most products sort themselves out.

1. The species, in Latin. Common names cover several species.
2. The part: fruiting body, mycelium, or mycelium with substrate.
3. A beta-glucan percentage, rather than a polysaccharide figure.
4. What the extraction ratio is measured against, if there is one.
5. What is tested, how often, and whether a result is available on request.
6. The per-dose weight, not the per-tub weight.

What is in a Chaski tube, and what we do not measure

Chaski Cacao is a 600 g tube of 77% dark chocolate buttons, daily dose four buttons. The cacao is single-origin Peruvian and Ecuadorian, ground at low temperature and sweetened with coconut sugar. No emulsifiers, no seed oils, no palm oil, no added cane sugar. The Lion's Mane is a fruiting body extract. The Cordyceps is Cordyceps sinensis, mycelium. The Ginkgo Biloba component is being replaced by 200 mg of Tremella fuciformis, a 10:1 fruiting body extract, per daily dose, and tubes are currently in that transition. Every batch is tested for lead, cadmium and pesticides.

Applying this page's own test to Chaski produces one honest gap. We do not publish a beta-glucan percentage, because we have not measured one, and a figure we have not measured is not a figure we will print. By the standard set out above, that is a question Chaski has not answered, and saying so is better than quoting a number from a supplier's brochure. The composition is on the Chaski Cacao product page. For the format question rather than the quality question, there is a comparison of chocolate and capsule formats, and the library is at the Chaski guides index.

Sources

1. Wu DT, Deng Y, Chen LX et al., Scientific Reports, 2017
2. Windsor C, Kreynes AE, Chilton JS et al., International Journal of Molecular Sciences, 2025