How much protein do worms have in them?

November 2, 2025 •

3 min read

According to the Food and Agriculture Organization, over two billion people worldwide already consume insects, including various types of worms, as a regular part of their diet. This practice of entomophagy is driven by the fact that many worms and other insects offer a surprisingly high-quality and sustainable protein source. But just how much protein do worms have in them?

Quick Summary

Worms offer a high-protein alternative to traditional livestock. On a dry-weight basis, protein content varies significantly by species and processing method, ranging from approximately 50% to over 70% in some cases. This makes them a viable nutritional option for animal feed and, in many cultures, human consumption.

Key Points

High Protein Content: On a dry-weight basis, many worms contain 50-70% crude protein, exceeding some conventional meat and plant sources.
Processing Matters: Drying worms significantly increases their protein concentration, as water accounts for a large percentage of a live worm's weight.
Rich in Essential Amino Acids: Worm protein typically provides a complete profile of essential amino acids, crucial for animal and human nutrition.
Species-Dependent Variations: The protein and fat content differs by species; for example, mealworms are fattier than European nightcrawlers.
Environmentally Sustainable: Farming worms requires minimal land and water compared to traditional livestock, making them a highly efficient protein source.
Promising Alternative Food Source: Edible worms have been approved for consumption in some regions and are being explored as a solution for global food security.

Worm Protein: A High-Quality, Nutrient-Dense Alternative

The nutritional value of worms, and edible insects in general, is gaining recognition as a viable and sustainable solution to growing global food demands. Beyond their crude protein content, worms also provide essential amino acids, healthy fats, vitamins, and minerals. However, the exact nutritional profile can vary dramatically depending on several key factors, including the worm species, its diet, its life stage, and how it is prepared.

Key Nutritional Factors in Worms

Species Variation

Different worm species have distinct nutritional compositions. Earthworms, for example, have been a subject of extensive research, particularly species like Eisenia fetida (red wigglers). Studies show that the dry-weight crude protein content for earthworms typically falls between 50% and 70%, surpassing that of some conventional protein sources like beef or soybeans. Meanwhile, yellow mealworms (Tenebrio molitor) and mopane worms (Gonimbrasia belina) also demonstrate high protein levels, with mealworms containing around 50-60% protein and mopane worms reaching nearly 60%.

Processing Method

How worms are prepared significantly affects their protein concentration. The removal of moisture is a crucial step. Dried worms, whether freeze-dried or oven-dried, contain a much higher concentration of protein by weight than fresh, live worms due to the removal of water. For instance, live mealworms may contain only 20% protein, while dried mealworms can pack an impressive 53%. Drying also makes the worms more shelf-stable and easier to process into protein meal or powder.

Live vs. Dried: A large portion of a live worm's weight is water. By removing this, the nutrient density increases significantly.
Gut Contents: For some species, the removal of gut contents can also increase the final protein percentage of the edible portion.
Thermal Processing: Studies have shown that different heating methods, such as freeze-drying versus oven-drying, can influence the retention of nutrients like protein.

The Amino Acid Profile

It's important to remember that protein quality isn't just about quantity, but also its amino acid profile. Most edible insects, including worms, contain all nine essential amino acids needed by humans and animals. In fact, the amino acid profile of earthworms is often compared favorably to high-quality protein sources like fish meal and soybean meal, particularly in terms of essential amino acids like lysine and methionine. This makes them a particularly valuable feed ingredient for livestock and aquaculture.

Worm Protein Content: A Comparison Table


Worm Species	Protein (% Dry Weight)	Fat (% Dry Weight)	Key Minerals	Notes
*Earthworm (Eisenia fetida)*	50–70%	7–10%	Calcium, Phosphorus, Iron	Can be processed into high-protein meal.
*Yellow Mealworm (Tenebrio molitor)*	47–64%	17–33%	Magnesium, Copper, Iron	Popular for both human and animal consumption.
*Mopane Worm (Gonimbrasia belina)*	~58%	~15%	Iron, Zinc, Omega-3	Traditionally consumed in Southern Africa.
*European Nightcrawler (Lumbricus terrestris)*	~61%	~4.4%	Calcium, Phosphorus	Known for lower fat content than other species.
*Silkworm Pupa (Bombyx mori)*	~56%	~30%	Iron, Magnesium	A byproduct of the silk industry, rich in fat.

Using Worms as a Sustainable Protein Source

The benefits of using worms and other insects as a protein source extend beyond their nutritional metrics to include significant environmental advantages. Insect farming requires substantially less land and water than traditional livestock farming and produces fewer greenhouse gas emissions. This makes it a highly efficient method for generating high-quality protein.

For those interested in farming worms, either for feed or food, resources are available to guide you through the process, such as those provided by the Penn State Extension. Whether for aquaculture, poultry, or direct human consumption, the production of insect protein is a growing industry with potential to impact food security positively on a global scale.

Conclusion

In conclusion, worms are a formidable protein source, with the exact protein content varying based on species, processing, and diet. When dried, many edible worms offer a protein concentration that rivals or even exceeds that of conventional meat and plant-based alternatives. Coupled with their favorable amino acid profiles and high sustainability, worms represent a promising alternative protein source for addressing future food demands. For consumers and farmers, understanding the variability and preparation methods is key to maximizing the nutritional benefits of this unassuming but mighty protein package.

Frequently Asked Questions

No, not all worms are safe for human or animal consumption. It is critical to only eat or feed purpose-raised, edible worm species. Wild worms can accumulate heavy metals or other toxins from their environment, posing a health risk.

Studies on different insect proteins show high digestibility, often comparable to conventional proteins. However, the presence of chitin in the exoskeleton can slightly reduce digestibility, though processing methods can help mitigate this.

The main difference is concentration. Live mealworms, for instance, are about 20% protein, while dried mealworms are over 50% protein by weight, because the drying process removes most of the water.

For animal feed, worm protein meal can be a highly effective and nutritious replacement for ingredients like fish meal or soybean meal. For human diets, edible worms offer a complete and high-quality protein source that can act as a substitute for or supplement to conventional meat, depending on preparation.

In addition to a high-quality protein, worms also contain essential amino acids, healthy fats (including Omega fatty acids), minerals like iron, zinc, and calcium, and vitamins, particularly B-complex vitamins.

Yes, insects and worms are widely regarded as a more sustainable protein source than traditional livestock. They require significantly less land, water, and feed to produce the same amount of protein.

Worms are often dried, ground into a fine powder or meal, and then used as an ingredient in other food or feed products. The drying process is key to concentrating the protein content and increasing shelf-life.