Among all edible mushrooms studied, Tricholoma species have the highest protein content at nearly 37 grams per 100 grams of dry weight. That puts them ahead of dozens of other varieties, though the mushrooms you’ll actually find at a grocery store tell a different, more modest story. Understanding the gap between dried and fresh mushroom protein numbers is key to using this information in your diet.
Highest-Protein Mushrooms by Dry Weight
When researchers measure protein across mushroom species, they use dried samples with all the water removed. On that basis, the rankings are clear. Tricholoma tops the list at 36.87 g per 100 g dry weight, followed by shaggy mane (Coprinus comatus) at 30.90 g, and termite mushrooms (Termitomyces macrocarpus) at 30.69 g. Straw mushrooms come in at 28.10 g, and the well-known morel reaches 25.85 g. Even shiitake, one of the most widely available specialty mushrooms, delivers a solid 23.26 g per 100 g dry weight.
For context, the average protein content across all edible mushroom species is about 23.80 g per 100 g dry weight. That’s a respectable number, comparable to many legumes on a dry-weight basis. At the bottom of the scale, chicken of the woods comes in at just 8.62 g, showing how much variation exists even within the mushroom kingdom.
Fresh Mushrooms Have Far Less Protein
Here’s the catch: mushrooms are roughly 90% water. When you buy fresh mushrooms at the store and weigh out 100 grams, you’re mostly weighing water. USDA data on raw, fresh mushrooms paints a very different picture from the dried figures above.
- White button mushrooms: 3.00 g protein per 100 g fresh
- Oyster mushrooms: 2.75 g per 100 g fresh
- Enoki mushrooms: 2.66 g per 100 g fresh
- Maitake mushrooms: 1.94 g per 100 g fresh
So if you’re eating fresh mushrooms straight from the produce section, white button mushrooms actually lead the pack at 3 grams per 100-gram serving. That’s roughly what you’d get from a heaping cup of sliced mushrooms. It’s not nothing, but it’s a fraction of what you’d get from the same weight of tofu (around 8 g), cooked lentils (around 9 g), or chicken breast (around 31 g).
Why Dry Weight Numbers Can Be Misleading
The 37-gram figure for Tricholoma is real, but it describes what’s left after all moisture is gone. You’d need to eat a very large quantity of fresh Tricholoma mushrooms to reach that protein level in a single sitting. Dried mushroom powders and extracts do concentrate the protein, which is one reason mushroom protein is gaining attention as a supplement ingredient. But if you’re tossing fresh mushrooms into a stir-fry, plan on them contributing flavor, fiber, and micronutrients more than meaningful protein.
Environmental factors also shift these numbers. Wild mushroom protein content varies depending on soil type, the ratio of carbon to nitrogen in the soil, tree canopy cover, and even the mix of tree species nearby. Two specimens of the same species picked from different forests can have noticeably different protein levels.
Mushroom Protein Quality
Protein quantity only tells part of the story. Your body also needs that protein to contain the right amino acids in usable proportions. Mushrooms do contain all nine essential amino acids, which technically makes them a complete protein. But the proportions aren’t ideal for human nutrition.
Researchers have measured how well your body can actually use mushroom protein using a standardized scoring method called PDCAAS, which rates protein quality on a scale from 0 to 1. Mushrooms score between 0.35 and 0.45, depending on the species. For comparison, eggs score 1.0, soy scores around 0.91, and most legumes fall between 0.5 and 0.7. Oyster mushrooms scored highest among those tested at 0.45, while Tricholoma species scored just 0.35, meaning their high protein content is partially offset by lower digestibility.
True protein digestibility (how much your body actually absorbs) ranged from about 53% to 81% across the species tested. That’s significantly lower than animal proteins, which typically exceed 90%. The practical takeaway: you absorb roughly half to three-quarters of the protein listed on the label for mushrooms, not all of it.
Best Ways to Get More Protein From Mushrooms
If you want to maximize the protein you get from mushrooms, a few strategies help. Cooking breaks down cell walls that are tough for your digestive system to handle, which improves how much protein your body can access. Dried mushrooms concentrate the protein by removing water, so adding dried shiitake or porcini to soups and sauces gives you more protein per gram than fresh ones. Mushroom powders made from high-protein species like shiitake or shaggy mane can be stirred into smoothies, broths, or sauces as a supplement.
Pairing mushrooms with complementary protein sources also makes sense. Since mushrooms are low in certain amino acids that legumes and grains supply well, combining them in the same meal gives you a more complete amino acid profile. A mushroom and lentil soup, for instance, covers more nutritional bases than either ingredient alone.
Mushrooms are best thought of as a protein contributor rather than a protein centerpiece. Their real strengths, beyond the modest protein, include B vitamins, selenium, potassium, and unique compounds like beta-glucans that support immune function. If you’re choosing mushrooms specifically for protein, go with white button or oyster varieties fresh, or dried shiitake and morels for concentrated protein per gram.