Why You Should Care about Amino Acids

I’m sure if you’re interested in Ray Peat’s ideas on metabolism, you’ve read that the amino acids cysteine, methionine, and tryptophan may reduce thyroid peroxidase output.  Peroxidase is associated with preventing high levels of hydrogen peroxide from accumulating in the body and causing gray hair and other problems as it is cytotoxic.  It’s actually really bizarre that some people consume hydrogen peroxide as a health thing.

I’m also sure you’ve read that tyrosine and phenylalanine are forming thyroid hormone, and that glycine and proline are anti-inflammatory simple amino acids.  Branched chain amino acids (BCAA) such as valine, isoleucine and leucine (along with lysine) may also be helpful in sustaining high levels of thyroid hormone T3.

With these thoughts in mind, it makes sense to maximize the “good” amino acids, and reduce intake of the “bad” amino acids.  One can also support the conversion of tryptophan into Niacin – a good thing Vitamin B-3 – by keeping optimal levels of the B6 coenzyme PLP in the body.

I made the following charts for you to easily use in deciding your optimal protein combinations.



Animal Proteins


Plant proteins

As you can see, gelatin is extremely high in glycine and proline, and low in tryptophan, methionine and cysteine.  Unfortunately, it’s completely lacking in BCAAs and tyrosine.  Whey is extremely high in BCAAs and still relatively low the thyroid limiting amino acids.  Egg whites stick out as being a little higher in methionine and cysteine while still low in tryptophan. Beef and chicken are comparable, and a little higher in tryptophan than milk while lower in methionine.  I don’t believe the data on goat milk not having any tryptophan – that’s just from the data source I used.

A possible good combination is whey, casein and gelatin to get the best of all worlds and minimal bad stuff.  I haven’t run any optimization to determine the ideal ratios in the mixture.  If someone has a method for doing this-some kind of matrix math and optimization equations, I’d be happy to enter it into my excel chart, and run the math.  I’ve been out of school too long to figure this out anymore.

Plant proteins can be considered, but depending on how they are processed, may not be ideal.  When rice and pea are combined they generally offset eachother’s weaknesses.

Unfortunately, this analysis didn’t include amounts of the potentially health amino acids Taurine and Carnosine.  

Carnosine is the combination of histidine and alanine and may contribute to anti-aging.  Carnosine is found in highest amounts in lean beef.  Taurine is found in high amounts in dairy and meat.

You can supplement with Taurine and Carnosine, but the risk with the supplement industry is you don’t know how individual amino acids are processed.  It’s ultimately your choice.  Sometimes avoiding things that may have potential downside (mercury, aluminum, toxins in general) is more important than focusing on their potential positives.

See my page for links to products mentioned in this article.  Naked Whey, Naked Casein, and Great Lakes Gelatin are all great choices for protein sources that are easy to digest and not too liquid heavy.  Overall, I think food sources (cheese, meat, milk, seafood) are preferred due to their nutrient contents.  However, we all live in a world without tons of time to chew up meat all day long. Protein is a nutrient in of itself.