Background

Threonine is an essential amino acid. Amino acids are the building blocks of proteins. It cannot be made by the body and must be consumed in foods.

Threonine is changed in the body to a chemical called glycine. Glycine has effects in the brain that might reduce unwanted muscle contractions called spasticity.

People use threonine for Lou Gehrig's disease (amyotrophic lateral sclerosis or ALS), multiple sclerosis (MS), and many other conditions, but there is no good scientific evidence to support these uses.

Don't confuse threonine with another amino acid called theanine. These are not the same.

Safety Safety definitions

When taken by mouth: Threonine is commonly consumed in foods. People need about 0.5-1 gram of threonine from their diet daily. This amount is considered safe. Threonine is possibly safe when used in larger amounts as a medicine. Doses of up to 4 grams daily have been used safely for up to 12 months. It seems to be well-tolerated. Side effects might include stomach upset, headache, nausea, and skin rash.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Threonine is commonly consumed in foods. But as medicine, there isn't enough reliable information to know if threonine is safe to use when pregnant or breast-feeding. Stay on the safe side and stick to food amounts.

Amyotrophic lateral sclerosis (Lou Gehrig's disease): There is some concern that threonine might decrease lung function in people with ALS. Talk to your healthcare provider before taking threonine if you have ALS.

Effectiveness

Dosing & administration

Threonine has most often been used by adults in doses of 1.5-2.5 grams by mouth three times daily for up to 8 weeks. A dose of up to 4 grams daily has been used for up to 12 months. Speak with a healthcare provider to find out what dose might be best for a specific condition.

Interactions with pharmaceuticals

Medications for Alzheimer disease (NMDA antagonists)

Interaction Rating=Major Do not take this combination.

Threonine might decrease the effects of medications for Alzheimer disease.

Interactions with herbs & supplements

Alanine: Threonine might compete with other amino acids such as alanine to gain access to the central nervous system (CNS). Taking alanine with threonine might decrease the effectiveness of threonine.
Branched-chain amino acids: Threonine might compete with other amino acids such as branched-chain amino acids to gain access to the central nervous system (CNS). Taking branched-chain amino acids with threonine might decrease the effectiveness of threonine.
Phenylalanine: Threonine might compete with other amino acids such as phenylalanine to gain access to the central nervous system (CNS). Taking phenylalanine with threonine might decrease the effectiveness of threonine.
Serine: Threonine might compete with other amino acids such as serine to gain access to the central nervous system (CNS). Taking serine with threonine might decrease the effectiveness of threonine.
Tryptophan: Threonine might compete with other amino acids such as tryptophan to gain access to the central nervous system (CNS). Taking tryptophan with threonine might decrease the effectiveness of threonine.
Tyrosine: Threonine might compete with other amino acids such as tyrosine to gain access to the central nervous system (CNS). Taking tyrosine with threonine might decrease the effectiveness of threonine.

Interactions with foods

There are no known interactions with foods.