Cs-4 and Cultured Cordyceps Mycelium

The short version. "Cs-4" is the name of one fungus strain, now called Paecilomyces hepiali, that scientists first isolated from wild caterpillar fungus in the early 1980s and that factories now grow in tanks as mycelium (the thread-like body of a fungus). [1] It is the fungus inside the Chinese medicine Jinshuibao and inside several "Cordyceps" supplements, including products sold in the West under the Cs-4 name. [1][12] It is not the wild caterpillar fungus, and it is not the fungus that Bailing capsules are made from. [1] Most of the human research is on Jinshuibao, mostly in China, mostly in kidney and lung patients, and the trials are small and of low quality. Reviews that pool them find signals on blood tests, not proof of health benefit. [4][5][6] Two small Western exercise trials of Cs-4 pointed in opposite directions. [9][10]

What it is, and what it is not

The wild "caterpillar fungus" is Ophiocordyceps sinensis, described on our caterpillar fungus page. When Chinese scientists tried to grow fungi from it in the 1970s and 1980s, they isolated several. [1] One of them, a strain named Cs-4, became Paecilomyces hepiali (the 1982 description). [1] A 2015 industry review makes three points that matter to a shopper. [1]

• P. hepiali was first described as the "anamorph" (the asexual form) of the wild fungus, but that description was not validly published. A different fungus, Hirsutella sinensis, is the one mycologists generally accept as the asexual form of O. sinensis. [1]
• The review states that P. hepiali is not the anamorph of O. sinensis, but belongs to the same broad group of cordyceps fungi. [1] The authors treat it as an independent cordyceps fungus rather than a cultured copy of the wild one. [1]
• Bailing capsules (also called Corbrin) are made by fermenting Hirsutella sinensis, a different organism from Cs-4. Jinshuibao is made by fermenting Cs-4 (P. hepiali). [1] A third fungus, Mortierella hepiali, goes into Zhiling capsules. [1]

So three different organisms are sold under the one word "Cordyceps", and all three are different from the wild fungus. Our page on the species question covers the other common mix-up, between Cordyceps militaris and O. sinensis.

Two separate questions: food and supplement

As a food. Cs-4 mycelium is not a food. It is an ingredient in capsules, tablets and powders. USDA FoodData Central has no record for it, and we found no open measured values for protein, vitamins or minerals in it. Proper evidence not found for a food-nutrition role.

As a supplement or medicine. In China, Jinshuibao capsules and tablets are sold as a regulated medicine. A 2015 review says they were approved by the national new-drug committee in 1989 and are used for conditions that include lung and kidney weakness, chronic cough, chronic bronchitis, chronic kidney insufficiency, fatigue and high blood fats. [1] That is the regulatory and traditional-medicine label: it describes how the product is positioned in China, not what trials prove. Outside China, Cs-4 products are sold as supplements, and a 2026 review notes that supplement products there typically use cultured mycelium (the "Cs-4" strain) rather than the wild fungus. [12]

Fruiting body versus mycelium

Cs-4 products are mycelium grown by fermentation, not a fruiting body and not mycelium grown on grain. [1] Fermentation in liquid gives a product that is mostly fungal biomass and its extracts, so it does not carry the leftover grain starch that mycelium-on-grain powders do. A 2025 review of caterpillar-fungus cultivation says fermented mycelium has a chemical profile distinct from the wild fungus. [12] See fruiting body versus mycelium and mycelium on grain. The practical point is the same one that runs through this site: a result from one form (here, tank-grown P. hepiali) does not transfer to the wild fungus, to Bailing, or to C. militaris products.

Traditional use

Traditional use only, not proof. Cs-4 is a modern, factory-made product, so it has no centuries-long history of its own; its reputation is borrowed from the wild fungus, which MSK says is used in traditional Chinese medicine for fatigue, sexual dysfunction and cough. [2] The Jinshuibao drug label lists a long set of uses (see above), which come from that tradition. [1] A tradition or a drug label is not evidence that a product works.

What research shows

The table says which product was tested, because that decides what a result can tell you.

How to read this. The Chinese reviews are consistent in direction but weak in quality: open-label or unblinded, short, done in one country, and often judged by blood and urine tests rather than by outcomes such as dialysis or death. [4][5][6][12] A 2026 review of caterpillar-fungus products concludes that this body of work does not meet the European Medicines Agency's standard for "well-established use". [12] The one head-to-head Western exercise pair (positive pilot, null trial) is a good reminder of how small the Western evidence is; see cordyceps for energy and exercise. One earlier Jinshuibao meta-analysis in diabetic nephropathy (2022) has been retracted by its journal, and we do not rely on it. [15]

We also saw that one 2026 review lists a long-COVID fatigue trial of Cs-4 (110 people, waitlist-controlled) with improvement in fatigue and quality of life. [12] We did not open the trial itself, so we mention it only as reported by the review; a waitlist comparison is not a placebo.

Forms you may see

• Jinshuibao capsules and tablets. The Chinese medicine made by fermenting Cs-4; the form in most Chinese trials. [1][4][5]
• Cs-4 capsules or tablets under supplement brand names. Used in the two US exercise trials; the label may say Cordyceps sinensis even though the organism is the cultured Cs-4 strain. [9][10][12]
• **Other P. hepiali mycelium extracts** (for example the Korean CBG-CS-2). Same species, different strain, different process; the immune trial used this. [11]
• Blends. Cs-4 may appear in multi-mushroom products, where the amount of each ingredient is often not stated. See single species versus blends.

Lab data and chemistry

This section is for readers who want to see what laboratories have measured. It does not show that Cs-4 does anything in people. Wikidata (the open knowledge base behind the LOTUS natural-products project) lists no compounds for Paecilomyces hepiali (Q10614990). [14] It does list 112 compounds for Hirsutella sinensis (Q398300), the fungus in Bailing, but none of those statements carries a paper reference in our extract and they describe a different organism, so we do not use that list for Cs-4. [14] The compound table below therefore rests on papers we opened.

A. What the laboratory literature reports in this fungus

Cordycepin, the compound most quoted for C. militaris, is reported at 0.001% in the P. hepiali extract above, so Cs-4 is not a cordycepin product. [11] Our page on cordycepin explains the compound.

B. Measured values

USDA FoodData Central has no record for Cs-4 or P. hepiali, so there are no USDA food values. We found no open measured value for ergothioneine, vitamin D, enzymatic beta-glucan, total triterpenes, arsenic or other metals in Cs-4 or Jinshuibao. The rows below are all we could find; each comes from one product.

C. What the numbers do and do not mean

• One product is not "Cs-4". The composition figures come from one Korean P. hepiali extract, which is a different strain and process from Jinshuibao or from US supplements sold under the Cs-4 name. Another maker's product could differ. [11]
• Compound percentages depend on the method. "Cordyceps polysaccharide" is a total-carbohydrate type measure, not the same as an enzymatic beta-glucan measure; see beta-glucans versus polysaccharides. A "standardised to polysaccharide" label says little about specific actives. [11]
• A test-tube antioxidant score is not a health effect. The FRAP number comes from one pharmacy sample and a laboratory assay. [3]
• Cs-4 is not a copy of the wild fungus. A study comparing wild cordyceps with Bailing and Jinshuibao samples found the metabolite profiles differed in several groups (for example the wild sample was richer in lipids and the P. hepiali sample in organic acids). Treat each as a different material. [3]
• Purity and metals are unmeasured here. Without an open measurement for arsenic or other metals in Cs-4 products, ask a seller for a certificate of analysis; see mushroom testing and certificates of analysis.

Related pages

Cordyceps overview, caterpillar fungus (Ophiocordyceps sinensis), Cordyceps militaris versus Ophiocordyceps sinensis, cordyceps for energy and exercise, cordyceps side effects and medicine cautions.