Written by the Spacemilk team · Last updated October 2026

Yeast protein is protein isolated from yeast, not yeast itself: there's no live or active yeast in Spacemilk, and it has 0g sugar and almost no fermentable carbs. Some people following a candida protocol choose it, so check with your provider. If you have a true baker's yeast allergy, which is extremely rare, talk to your allergist before using it, because the protein is still yeast-derived.

Does yeast protein contain live yeast?

No. Spacemilk is made from non-GMO baker's yeast (Saccharomyces cerevisiae), the yeast behind bread, beer and wine. We grow the yeast in water through fermentation, gently break it down with heat, then filter out the protein and dry it. The protein is separated from the yeast along the way, so what's in the bag is protein isolate with no live or active yeast.

That's also what makes it different from the yeast products you may already know:

Product	What it is	Live yeast?
Baker's yeast (active dry or fresh)	Whole, living yeast cells used to raise bread	Yes
Nutritional yeast	Whole yeast cells, deactivated and dried into flakes	No, but the whole cell is there
Brewer's yeast supplement	Whole yeast from brewing, deactivated and dried	No, but the whole cell is there
Spacemilk yeast protein	The protein isolated from baker's yeast, with the rest of the yeast filtered out	No

Because it's protein isolated from a single-celled organism, Spacemilk is a single-cell protein. Each serving delivers 20g of complete protein with a perfect protein quality score (PDCAAS 1.0).

Can you have yeast protein with a yeast allergy?

If you have a true baker's yeast allergy (IgE-mediated), check with your allergist before using Spacemilk. The yeast is removed during isolation, but the protein itself is yeast-derived, and an allergy is a reaction to proteins. We'd rather say that plainly than play it down.

The good news is that this allergy is extremely rare. A peer-reviewed review of yeast protein as a food source notes that serious yeast allergies are reported very rarely, with people who inhale yeast at work most at risk (Jach et al., 2022, Metabolites). Your allergist can tell you whether that applies to you, and whether testing makes sense first.

Is a yeast allergy the same as sensitivity to fermented foods?

No. Some people find they don't get along with fermented foods like kombucha, sauerkraut or aged cheese. That's not the same thing as an allergy to yeast protein. Spacemilk contains no live or inactive yeast cells and tests non-detectable for histamine.

Is yeast protein free from major allergens?

Yes. Spacemilk is free from all nine major food allergens recognized by the FDA (FDA): dairy, soy, gluten, eggs, tree nuts, peanuts, fish, shellfish and sesame. Yeast isn't one of the nine, which is why we call out the yeast allergy separately.

• Every batch is tested for gluten, dairy, soy and peanuts.
• It's gluten-free: every lot tests under 5 ppm, against the FDA's 20 ppm line.
• It's vegan, with no ingredients from mammals.

Every result is published on our testing page, where you can match the lot code on your bag.

Can you have yeast protein if you're following a candida protocol?

Spacemilk has 0g sugar, almost no fermentable carbs, and our process leaves no live or active yeast, just isolated protein. Some people following a candida protocol choose it. Check with your provider, who knows your plan and history.

A few facts that help when you're weighing it up:

• Different organism. Spacemilk is made from Saccharomyces cerevisiae, baker's yeast. Candida is a different genus of yeast.
• No live or active yeast. The protein is separated from the yeast during production. What's in the bag is protein isolate.
• 0g sugar. The flavored versions are sweetened with Reb M, a sweetener fermented from rice, and thaumatin. Unflavored has one ingredient: yeast protein isolate.
• Very low in fermentable carbs. It's formulated to be low in FODMAPs, with no lactose and no sugar alcohols.

To be clear about what this page is and isn't: these are facts about what's in the product. Spacemilk isn't a treatment for candida or any other condition, and it isn't a substitute for advice from your provider.

Is yeast protein easy to digest?

Spacemilk is easy to digest because of what's left out: no lactose, no sugar alcohols, no gums like xanthan or guar, and no plant material. It's formulated to be low in FODMAPs, and many customers describe it as light on their stomach. In a laboratory model of human digestion, yeast protein's digestibility was comparable to whey's (Caron et al., 2025, Food Research International). For the full head-to-head, read Yeast protein vs whey.

Who it's for, and who should check with a doctor

Yeast protein may suit you if you avoid dairy or other major allergens, you're wary of anything with live yeast in it, or you want a protein that's low in fermentable carbs.

Check with your doctor or allergist first if you have a known or suspected yeast allergy, you've reacted to yeast-containing foods before, you're following a candida protocol or other plan set by your provider, you're immunocompromised, or you're pregnant or nursing. Parents choosing a protein for a child should ask their pediatrician.

Frequently asked questions

Is Spacemilk yeast-free?

It's made from yeast, so we don't call it yeast-free. It contains no live or active yeast: the protein is separated from the yeast during production, and what's in the bag is just the protein.

Is yeast protein the same as nutritional yeast?

No. Nutritional yeast is whole, deactivated yeast flakes. Spacemilk is the protein isolated from baker's yeast, with the rest of the yeast filtered out. It doesn't taste like nutritional yeast either.

Can people with a yeast allergy use yeast protein?

If you have a true baker's yeast allergy, check with your allergist first. The yeast is removed during isolation, but the protein is yeast-derived.

Is yeast protein high in purines like whole yeast?

No. Spacemilk has about 38mg of purines per serving. Whole yeast runs much higher. See Yeast protein, purines and gout for the comparison.

Where can I find more answers?

Our FAQ covers ingredients, allergens and testing, and our Science page summarizes the published research on yeast protein. Ready to try it? Shop Spacemilk Complete Protein.