Space Milk (baker's yeast protein) as a plant-based alternative to whey
A new protein made from baker's yeast is marketed as outperforming whey, but a deep dive into the underlying study reveals equivalent results and unsubstantiated satiety claims; its amino acid score (PDCAAS 1) and profile make it the best plant protein Layne has seen, though it costs 30–40% more per gram of protein than whey isolate.
Why this matters: A rare plant-based protein with a perfect PDCAAS score and nearly whey-equivalent leucine content, yet the marketing overstates the evidence, underscoring how even high-quality ingredients get wrapped in misleading hype.
Plant proteins often lack sufficient leucine or have lower PDCAAS scores, requiring larger doses or blends to match animal proteins. Space Milk enters as a novel yeast-derived isolate claiming to solve these issues and even surpass whey.
Layne went to the Space Milk website and examined the human study they cite. The trial compared baker's yeast protein, whey protein, and a placebo alongside resistance training. The charts were presented in a way that made whey look slightly worse, but closer inspection showed whey actually did numerically better for lean mass, while yeast did better on bench press and whey on leg press—none of these differences were statistically significant. Layne calls this pattern 'pee hacking' (p-hacking): test enough outcomes and a difference will eventually pop up, creating a false narrative of superiority. He emphasizes the study really tells us the two proteins are equivalent.
On the satiety claim: Space Milk says the protein is slow-release and therefore keeps you fuller longer, but the study never measured satiety. Slower digestion doesn't automatically translate to greater fullness, so the claim is unsupported by any data.
Amino acid analysis shows the yeast protein is very close to whey: leucine is about 10% lower, total essential amino acids less than 5% lower, and the PDCAAS is 1.0 (same as whey and egg). Layne states it's probably the best amino acid profile he has seen among plant proteins. For vegans or those with dairy allergies, it's a highly viable option. However, on a cost basis for the same benefit, you pay 30–40% more for Space Milk compared to a standard whey isolate (e.g., Outwork Nutrition), and you get slightly more carbohydrate per serving. He concludes the protein itself is good, but the marketing claims are overblown—it does not outperform whey.
Layne personally examined the study, the product website, and the amino acid data; he references his own brand, Outwork Nutrition, as the benchmark for cost comparison, noting he formulated a whey isolate that provides the same benefit at a lower price per gram of protein.
It is not better than whey and on a per cost basis for the benefits, you have to pay more to get the same benefit.