Related Terms

• 2-Amino-3-hydroxybutyric acid, glycine, L-(-)-threonine, L-thréonine (French), serine, (S)-threonine, threonine, thréonine (French), threoninum (Latin), treonina (Spanish).

Background

• Threonine is an important amino acid that is a building block for proteins in the body. Some foods that are high in L-threonine are cottage cheese, watercress, sesame seeds, soy, meat and fish, lentils, eggs, milk, and gelatin.

• L-threonine has been studied in the treatment of nerve disorders like amyotrophic lateral sclerosis (ALS), multiple sclerosis, and muscle spasms. However, more research is needed.

Scientific Evidence

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

• Energy, HIV, immune function, mental illness, muscle strength, nervous system disorders, skin care, stomach complaints, stress, tooth disease.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (18 years and older)

• To treat amyotrophic lateral sclerosis (ALS), two grams of L-threonine has been taken by mouth once daily for one week.

• To treat multiple sclerosis, 7.5 grams of L-threonine has been taken by mouth daily in three divided doses for eight weeks.

• To treat muscle spasms, 4.5 grams or six grams of L-threonine has been taken by mouth daily in three divided doses for two weeks.

• To treat muscle spasms caused by spinal cord injury, six grams of L-threonine has been taken by mouth daily in three divided doses for up to two weeks.

Children (under 18 years old)

• There is no proven safe or effective dose for L-threonine in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

• Avoid if allergic or sensitive to L-threonine or to ingredients found in L-threonine supplements.

Side Effects and Warnings

• L-threonine is likely safe when taken by mouth in recommended doses in healthy people for up to one year.

• L-threonine may cause side effects such as constipation, diarrhea, gas, headaches, indigestion, nausea, runny nose, skin rash or warmth, or upset stomach.

• Use cautiously in people who have amyotrophic lateral sclerosis (ALS). Some research suggests that L-threonine may decrease survival in people with ALS.

• Use cautiously in people who have stomach disorders.

• Avoid in people who have Alzheimer's disease or those taking NMDA antagonists. L-threonine may decrease the effectiveness of these drugs in people who have Alzheimer's.

• Avoid in children and in pregnant or breastfeeding women, due to a lack of safety data.

• Avoid if allergic or sensitive to L-threonine or to ingredients found in L-threonine supplements.

Pregnancy and Breastfeeding

• There is currently a lack of scientific evidence on the use of L-threonine during pregnancy or breastfeeding.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

• L-threonine may interact with agents that may affect the nervous system, agents that may treat Alzheimer's disease, agents that may treat skin disorders, agents that may treat stomach disorders, agents that may treat stuffy nose, cholesterol-lowering agents, medroxyprogesterone acetate, muscle relaxants, NMDA antagonists, and pain relievers.

Interactions with Herbs and Dietary Supplements

• L-threonine may increase the absorption of nutrients in the body.

• L-threonine may interact with cholesterol-lowering herbs and supplements, herbs and supplements that may affect the nervous system, herbs and supplements that may treat Alzheimer's disease, herbs and supplements that may treat skin disorders, herbs and supplements that may treat stomach disorders, herbs and supplements that may treat stuffy nose, L-tryptophan, muscle relaxants, and pain relievers.

Author Information

• This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

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