It is surprisingly difficult to find the amino acid profile of nutritional yeast.
I had to dig around for a while, but eventually I found a study that had it (1).
The table below shows the data from that study, plus the amount needed to be considered a complete protein by the World Health Organization (WHO).
Note that amino acid profiles always fluctuate a bit depending on the manufacturer (for all foods, not just yeast), but this gives us a good idea of what to expect.
|Essential Amino Acid||Yeast mg/g protein||Complete protein mg/g (2)|
It’s a very balanced profile overall.
I think it’s safe to say that nutritional yeast is a complete protein, or extremely close to it.
Even though it falls a tiny bit short on methionine, that’s not really a fair comparison. The 16 mg/g from WHO is for methionine plus cysteine. The data for cysteine wasn’t available for nutritional yeast, but it’s a safe bet that it’s over 2.