Other Name(s):

L-threonine, L-thréonine, Thréonine, Treonina.


Threonine is an amino acid. Amino acids are the building blocks the body uses to make proteins.

Threonine is used to treat various nervous system disorders including spinal spasticity, multiple sclerosis, familial spastic paraparesis, and amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease).

How does it work?

Threonine is changed in the body to a chemical called glycine. Glycine works in the brain to reduce constant and unwanted muscle contractions (spasticity).


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Uses & Effectiveness

Possibly Ineffective for...

  • Amyotrophic lateral sclerosis (Lou Gehrig's disease). Taking 2 grams to 4 grams of threonine daily for up to 12 months does not seem to slow the progression of ALS or reduce symptoms. There is also some evidence that threonine might actually worsen lung function in people with ALS.

Insufficient Evidence to Rate Effectiveness for...

  • Familial spastic paraparesis, a hereditary disorder. Early research suggests that taking 1.5 grams to 2 grams of threonine by mouth three times daily might improve some symptoms in people with familial spastic paraparesis. But the improvement does not seem to be very significant.
  • Multiple sclerosis. Early research suggests that taking 2.5 grams of threonine by mouth three times daily for 8 weeks does not reduce muscle stiffness (spasticity) in people with MS.
  • Spinal spasticity, a movement disorder caused by spinal cord damage. Early research suggests that taking 2 grams of threonine by mouth three times daily modestly decreases muscle contractions in people with spinal spasticity caused by spinal cord injury.
  • Other conditions.
More evidence is needed to rate the effectiveness of threonine for these uses.

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, and Insufficient Evidence to Rate (detailed description of each of the ratings).

Side Effects

Threonine is POSSIBLY SAFE when doses of up to 4 grams daily are taken by mouth for up to 12 months. Some people experience minor side effects such as stomach upset, headache, nausea, and skin rash.


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Special Precautions & Warnings

Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking threonine if you are pregnant or breast-feeding. Stay on the safe side and avoid use.

Amyotrophic lateral sclerosis (Lou Gehrig's disease):There is some concern that threonine might decrease lung function in patients with ALS. In one study, ALS patients taking 1 gram of threonine four times per day for 6 months had significantly reduced lung function compared to patients who did not receive threonine. More evidence is needed to determine if threonine was actually at fault.


Medications used for Alzheimer's disease (NMDA antagonists)Interaction Rating: Major Do not take this combination.

There is some concern that threonine might decrease how well a medication used for Alzheimer's disease works. This medication is called memantine (Namenda).


The following doses have been studied in scientific research:


  • For a certain movement disorder due to spinal cord damage (spinal spasticity): 6 grams of threonine per day.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.


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Blin, O., Serratrice, G., Pouget, J., Aubrespy, G., Guelton, C., and Crevat, A. [Short-term double-blind vs placebo trial of L-threonine in amyotrophic lateral sclerosis]. Presse Med. 9-30-1989;18(30):1469-1470. View abstract.

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