Mycoprotein is a protein-rich food made from a naturally occurring fungus, grown through fermentation in large tanks. It contains about 11 grams of protein and 6 grams of fiber per 100 grams, making it one of the most nutritionally dense meat alternatives available. You’ll most commonly find it sold under the brand name Quorn, though the ingredient itself is increasingly used by other manufacturers.
How Mycoprotein Is Made
The organism behind mycoprotein is a soil fungus called Fusarium venenatum, originally identified in the 1960s during a search for new protein sources. Despite the name, which reflects its classification within a broader fungal group, the strain used for food production does not produce harmful toxins. It was specifically selected because it efficiently converts simple sugars into protein-rich biomass.
Production takes place in large aerobic airlift bioreactors that run continuously. The fungus feeds on a highly refined glucose syrup along with nitrogen sources like ammonia. As it grows, it forms long, branching filaments called hyphae. These filaments naturally interweave to create a fibrous structure that closely resembles the texture of animal muscle tissue. This is a key reason mycoprotein works so well as a meat substitute: the “meatiness” comes from the biology of the fungus itself, not from heavy processing or additives.
After fermentation, the raw biomass goes through a heat treatment at around 68°C for 15 to 30 minutes. This step reduces RNA content, which would otherwise be too high for regular human consumption. The heating causes roughly a 30% loss of total solids, so the process sacrifices some yield for safety. The mycoprotein is then chilled to near 0°C and shipped for further processing, where it gets formed into blocks, steamed to 90°C, and rapidly frozen to create the final product sold in stores.
Nutritional Profile
Per 100 grams of wet weight, mycoprotein delivers 85 calories, 11 grams of protein, 6 grams of dietary fiber, and just 2.9 grams of total fat (only 0.7 grams of which is saturated). By dry weight, the numbers are even more striking: roughly 45% protein and 25% fiber. That fiber content sets it apart from virtually every other protein source, plant or animal.
Mycoprotein qualifies as a complete protein, meaning it contains all nine essential amino acids your body can’t make on its own. Its protein digestibility-corrected amino acid score (PDCAAS) is 0.996 out of a possible 1.0, measured using gold-standard methods. That puts it on par with eggs and milk. In fact, the total essential amino acid content of mycoprotein is 21.1 grams per 100 grams of dry weight, which is higher than both lean cooked beef (14.8 g) and skinless cooked chicken (14.1 g).
One thing to note: mycoprotein is not a significant natural source of vitamin B12 or iron, nutrients that people reducing their meat intake often need to watch. Many commercial products are fortified with these, so check labels if this matters for your diet.
Muscle Building and Recovery
A controlled trial published in the American Journal of Clinical Nutrition compared mycoprotein head-to-head with milk protein in resistance-trained young men. Both foods were matched for leucine, the amino acid most important for triggering muscle repair. After a single meal, mycoprotein stimulated muscle protein synthesis to a significantly greater degree than milk, both in resting muscle and in muscle that had just been exercised. The rate of increase in protein synthesis was roughly double with mycoprotein compared to milk.
This was a somewhat surprising result, since milk protein (particularly whey) has long been considered the gold standard for post-workout recovery. The researchers attributed the difference partly to the unique matrix of mycoprotein, where protein is embedded within fiber and other cellular components, potentially slowing digestion and prolonging the muscle-building signal.
Effects on Blood Sugar and Cholesterol
In a randomized controlled trial involving people with type 2 diabetes, mycoprotein lowered post-meal blood glucose levels compared to control meals, without significantly changing insulin output. This suggests the high fiber content helps moderate the blood sugar response to a meal, a practical benefit for anyone managing blood sugar.
The cholesterol data is also encouraging. In a clinical trial, participants who ate mycoprotein regularly for several weeks saw a 13% reduction in total plasma cholesterol and a 9% decrease in LDL (“bad”) cholesterol. The control group, by contrast, saw their LDL actually increase by 12% over the same period. The low saturated fat content and high fiber content likely both contribute to this effect.
Environmental Footprint
Mycoprotein’s environmental profile is a mixed picture. Its carbon footprint sits at roughly 5.5 to 6.2 kg of CO₂ equivalent per kilogram of product. That’s comparable to pork (4 to 6 kg CO₂eq) and actually higher than chicken (2 to 4 kg CO₂eq). It’s substantially lower than beef, but it’s not the lightest option available. Soy protein, for instance, ranks among the least impactful protein sources across most environmental categories.
Where mycoprotein genuinely excels is in land and water use. It requires less than 2 square meters of land per kilogram, compared to 5 to 7 for chicken and 7 to 8 for pork. Water consumption runs around 500 liters per kilogram. Researchers have also modeled scenarios where mycoprotein is produced from agricultural waste streams instead of refined glucose, which could cut the carbon footprint to 2 to 4 kg CO₂eq, halve water use to around 250 liters, and reduce land requirements to just 0.5 square meters per kilogram.
Safety and Allergic Reactions
Mycoprotein has been approved for sale in the US, UK, and across Europe for decades. Some consumers have reported gastrointestinal symptoms like nausea or stomach discomfort after eating it, particularly on first exposure. True allergic reactions, involving an immune response, do occur but are exceptionally rare based on systematic evidence reviews.
People with known mold allergies may be at slightly higher risk. One documented case involved a patient allergic to mold fungi who experienced an immediate allergic reaction after eating mycoprotein, traced to a specific protein shared between mold species. Testing showed that about 35% of people already sensitized to a related mold species had immune reactivity to a protein found in the fungus. If you have a diagnosed mold allergy, it’s worth being cautious the first time you try it.
How It’s Used in Food
The natural fibrous structure of mycoprotein gives it a convincing meat-like chew without the need for complex texturizing. The branching fungal filaments mimic the way muscle fibers are arranged, which is why products made from it tend to work better in applications like chicken-style nuggets, ground meat substitutes, and deli slices than many plant-based alternatives made from isolated proteins. It has a relatively neutral flavor, so it absorbs marinades and seasonings well. You’ll find it frozen in most major grocery stores, typically as pre-seasoned pieces, patties, or ground-style crumbles ready for cooking.