L-Threonine
Threonine is an essential amino acid: the body cannot make it and needs it from food to build proteins.
Also listed as Threonine
What it is studied for
The strongest rated effects first. Bars show the size of the effect, the letter grades the evidence, and each rating lists the studies behind it.
What is threonine doing in the body?
Threonine is one of the amino acids the body needs from food to make proteins. An inadequate supply of an essential amino acid can limit protein production. Meeting that nutritional need does not by itself establish a benefit from a separate supplement. 1
Why people take it
SuppCo community snapshot, 2026-09-28. Reasons for use are not evidence that it works.
Questions people ask
Must threonine come from food?
Yes. It is an essential amino acid, meaning the body depends on a dietary supply. 1
Does the mucus connection mean it treats gut problems?
No. The cited evidence explains an animal-based mechanism; it does not establish relief of human digestive symptoms. 2
Should I copy the trial’s 12 g dose?
That amount was a short-term safety test in selected healthy men, not an intake recommendation. 3
Lysine
Leucine
L-Methionine