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Why do we react to glutathione precursors or other amino acid supplements?


Senior Member
Meats have much higher individual component of amino acid compared to usual supplemental dosage. The most common meats we consume like beef, chicken, and pork contain very high levels of glutamate, along with lysine and other BCAA's. Even an egg has around 800 mg, 200 mg, 140 mg of glumate, glycine, and cysteine respectively. Most people are fine with consuming meat, but have difficult times dealing with supplemental amino acid. My personal experience definitely reflects this. Thus, I have some questions in regards to this conundrum.

1. Why do many people react to glutathione precursors (glutamate, glycine, cysteine) or amino acid supplements when consuming meats do not result in the same issue?
2. Wouldn't consuming enough meats or other foods that are high in protein lead to glutathione synthesis?
3. What determines glutathione synthesis pathway?
4. Do negative reactions from AA supplement happen because of absence of cofactors like iron that are present in the meat?
5. Is consuming individual amino acid different from consuming a mixture of amino acids? If so, is supplementing amino acid a bad idea?

These questions have been bothering me for quite some time, but I still do not know the answers... Any insight would be greatly appreciated.


Certified in Environmental Medicine, ATSDR
I can offer some general insights. Cysteine is toxic all by itself. In meat, its not isolated, Its bonded. It has to be broken down to be utilized. That happens at a slow rate. Our bodies can handle it at the rate present by digestion, even when they can't utilize it due to metabolic errors. Glutamate is an excitatory neurotoxin, when unbonded. L-glutamate is safe, D-glutamate, the unbonded form is free MSG by process. Again, if we eat food with it in there (unless you have a severe sensitivity) we can deal with it because its broken down more slowly. Supplemental forms provide so much at once, our impaired systems can't process it fast enough.

Then, there's the purity factor. Many supplements are grown on petroleum based mediums and/or are by-products of black molds. While people with functioning immune systems can handle this, those of us with impairments get overwhelmed. We end up with adverse reactions.