Written by the Spacemilk team · Last updated October 2026

Yes. Yeast protein is vegan. Yeast is a single-celled fungus, not an animal, so a protein isolated from it involves no animal ingredients. The one thing to check is the rest of the label, since some powders blend in milk, egg or other animal ingredients.

What does "vegan" mean?

The Vegan Society, which coined the word, defines veganism as a way of living that "seeks to exclude—as far as is possible and practicable—all forms of exploitation of, and cruelty to, animals." In food terms, it means "dispensing with all products derived wholly or partly from animals" (The Vegan Society).

So the question for any food is simple. Did any part of it come from an animal? Meat, fish, dairy, eggs, honey and gelatin are out. Plants, minerals, algae and fungi are in.

Is yeast an animal, a plant or something else?

Neither. Yeasts are single-celled fungi. Britannica describes them as "any of about 1,500 species of single-celled fungi" and notes that the yeasts used to make bread, beer and wine are selected strains of Saccharomyces cerevisiae (Britannica). That's baker's yeast, the same species Spacemilk's protein comes from.

Fungi are their own group of living things. They aren't plants, and they aren't animals. Mushrooms are fungi too.

Why do some people ask whether yeast is vegan?

Because yeast is alive while it grows. But being alive isn't what veganism is about. Plants are alive as well. Veganism is about avoiding harm to animals. A yeast cell is a single cell with no brain or nervous system, and it isn't an animal.

How is yeast protein made?

Yeast protein is not the same as eating whole yeast. The protein is separated from the rest of the cell. Here is the general process behind Spacemilk:

1. Grow. Baker's yeast is grown in water in stainless-steel tanks, fed sugar plus vitamins and minerals.
2. Break open. Gentle heat, mild pH and the yeast's own enzymes break the cells apart.
3. Separate. A centrifuge spins out the protein-rich portion.
4. Pasteurize and dry. The protein is pasteurized, spray-dried into a powder and tested.

What's left is pure protein isolated from yeast. There's no live or active yeast in the bag. For a deeper look, read our guide to what yeast protein is.

Is yeast protein plant-based?

No, and the difference matters if you're reading labels closely. "Plant-based" means made from plants. Yeast protein is a single-cell protein from a fungus. It's vegan and 100% animal-free, but it isn't plant protein.

That's also why it behaves differently from plant proteins. It doesn't carry the plant fiber and compounds that some people find hard to digest. If you're comparing options, see yeast protein vs pea protein.

Is yeast protein the same as nutritional yeast?

No. Nutritional yeast is whole, deactivated yeast, usually sold as flakes for flavor. Yeast protein is the protein isolated from the yeast cell, sold as a powder. Both come from Saccharomyces cerevisiae, and both are vegan, but they're very different foods. Our guide to nutritional yeast vs yeast protein covers the details.

Can a "vegan" protein powder still contain animal ingredients?

The protein source is only part of the label. Blends and added ingredients deserve a second look.

The "Contains" statement

US labels must declare the major food allergens, including milk, eggs, fish and shellfish. That can appear in the ingredient list or in a "Contains" statement next to it (FDA). If you see milk, eggs, fish or shellfish there, the product isn't vegan.

Quick label checklist

Look for	Why it matters
Whey, casein, caseinate, milk protein	All come from milk
Egg white, albumen	Come from eggs
Collagen, gelatin, bone broth	Come from animal tissue
"Contains: milk" or "Contains: egg"	A required allergen declaration

Is yeast protein a complete protein?

Yes. A complete protein has all nine essential amino acids in useful amounts. The PDCAAS score rates protein quality on a scale with 1.0 at the top. Spacemilk's yeast protein scores 1.0. Here is how common vegan proteins compare with whey, using published values:

Protein	Vegan?	PDCAAS
Yeast protein (Spacemilk)	Yes	1.0
Whey protein isolate	No (dairy)	1.00
Soy protein isolate	Yes	0.98
Pea protein	Yes	0.89
Rice protein concentrate	Yes	0.42

Whey, soy, pea and rice values from Phillips, 2016, Nutrition & Metabolism, Table 1. Values can vary by product and lab.

Lower-scoring proteins are still useful. Vegans often combine sources across the day to cover every amino acid. A complete protein just makes that easier. Our guide to the PDCAAS protein quality score explains how the number is calculated.

What does the research show for muscle?

Yeast protein, the protein in Spacemilk, was shown in a 2024 double-blind randomized controlled trial to match whey for building lean muscle and strength in men over 40 doing resistance training. The study was placebo-controlled (Briskey et al., 2024).

That matters for vegans who lift. Protein helps build and repair muscle, and the quality of that protein counts.

Is yeast protein better for the planet?

Yes, and it isn't a small difference. Spacemilk is grown in water, not farmland, with about a 95% lower carbon footprint than beef protein.

Look at where most protein powders come from. Whey, casein, beef and collagen come from animals. Pea, soy and rice come from crops grown in soil. Either way, the protein starts on a farm.

Spacemilk doesn't. Baker's yeast grows in water inside stainless-steel tanks. No herds. No pasture. No plowed fields to grow the protein. It grows year-round, whatever the season or the weather.

Fermentation gave us sourdough, kimchi and kombucha. Now it gives us protein. If you went vegan for the planet, yeast protein is built for that choice.

Where does Spacemilk fit?

Spacemilk Complete Protein is the first protein made from baker's yeast. It's vegan and 100% animal-free. Each serving gives you 20g complete protein (PDCAAS 1.0) with 0g sugar. It's free from all 9 major allergens: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soy and sesame.

Unflavored is one ingredient: yeast protein isolate. The flavored versions add konjac fiber (a fiber, not a gum), sunflower lecithin and Reb M, a sweetener fermented from rice. Most flavors also use thaumatin. Every batch is third-party tested, and the results are on our testing page.

Who should check with a doctor first?

• You have a known yeast allergy. Ask your allergist first. Our guide on yeast protein, yeast allergy and candida has more.
• You're pregnant or breastfeeding.
• You have kidney disease or have been told to limit protein.
• You're planning protein for a child. Ask your pediatrician.
• You take medications or manage a condition that affects your diet.

This page shares nutrition facts and published information, not medical advice.

FAQ

Is baker's yeast vegan?

Yes. Baker's yeast is a single-celled fungus. It isn't an animal and isn't made from animals.

Is Spacemilk vegan?

Yes. Spacemilk is 100% animal-free, with no dairy, eggs or other animal ingredients in any flavor.

Does yeast protein contain live yeast?

No. The protein is isolated from the yeast, pasteurized and dried. There's no live or active yeast in Spacemilk.

Is yeast protein plant-based?

No. It's vegan, but it comes from a fungus, not a plant. "Single-cell protein" is the accurate term.

Do vegans eat fungi?

Yes. Veganism excludes animal products. Fungi such as mushrooms and yeast are not animals.

Sources

• The Vegan Society. Definition of veganism. vegansociety.com
• Encyclopaedia Britannica. Yeast (fungus). britannica.com
• US Food and Drug Administration. FASTER Act: Sesame Is the Ninth Major Food Allergen. fda.gov
• Phillips SM. The impact of protein quality on the promotion of resistance exercise-induced changes in muscle mass. Nutr Metab. 2016;13:64. doi:10.1186/s12986-016-0124-8
• Briskey D, et al. Journal of Food and Nutrition Research. 2024;12(5):292–300. doi:10.12691/jfnr-12-5-9