What Is Threonine? Essential Amino Acid Health Guide

Threonine, or L-Threonine, is one of 20 amino acids. It makes up the protein in teeth, enamel, collagen, and elastin (2). It’s even found in high quantities in the heart. Put simply, it’s a powerful building block that keeps the body (and heart) strong, healthy, and youthful.

Threonine is an “essential” amino acid, meaning your body can’t produce it on its own. Because of this, it must be obtained from food or dietary supplements like collagen powder.

Here’s a little science lesson for you: Threonine creates two other amino acids—glycine and serine (3).

These two conditionally essential amino acids are crucial to the creation of muscle tissue, collagen, and elastin. Collagen is the most important protein produced by the human body, and glycine is the most abundant amino acid in collagen—making up 33% of it (4).

Glycine acts as a neurotransmitter in the central nervous system, playing the role of antioxidant, anti-inflammatory, cryoprotective, and immunomodulatory in peripheral and nervous tissue. Supplementation of glycine has been shown to decrease cardiovascular disease, various inflammatory diseases, osteoarthritis, cancers, diabetes, and obesity (5, 6).

Serine, on the other hand, plays a central role in cell production and in the central nervous system. Without it, brain development and functioning withers, and neurological issues arise (7).

L-Threonine is a significant amino acid for the central nervous system, immune system, liver, and more.

A full list of threonine’s potential health benefits includes (2):

• Can metabolize fat
• May prevent fat buildup in the liver
• Can alleviate indigestion
• May reduce symptoms of anxiety and mild depression
• Can promote connective tissue and bone health
• Help maintain dental health
• May relieve symptoms of Celiac disease
• Can promote sleep

Without threonine, several issues arise, including (8, 9):

• Gastrointestinal disorder (like eosinophilic esophagitis or colorectal cancer)
• Neurological dysfunction (like Schizophrenia)
• Nervous system disorder (like epilepsy or Alzheimer’s disease)
• Reduces the growth of the small intestine, liver, and skeletal muscle
• Obesity
• Heart failure

Foods that are rich in threonine include (10):

• Lean grass-fed beef
• Pasture-raised chicken
• Pork
• Tuna
• Green peas
• Eggs
• Seeds
• Nuts

The amount of amino acids you consume each day depends on certain key factors like age, level of physical activity, overall health, and whether you’re wanting to get a specific outcome.

However, the recommended amount of threonine that one should get from their diet ranges from 400 to over 1,000 milligrams per day (11).

Here’s the full breakdown of threonine dosage, based on gender, age, and life stage.

When taken as a capsule for medicinal purposes, threonine doses of up to 4 grams daily for up to 12 months are regarded as safe.

Some individuals experience minor side effects such as an upset stomach, headache, nausea, and skin rash.

For those with ALS (amyotrophic lateral sclerosis, or Lou Gehrig’s disease), threonine may be a concern when it comes to lung function. In one double-blind study, 95 patients with ALS were given either BCAAs, L-Threonine, or a placebo for 6 months. For those receiving the BCAAs and threonine, lung function decreased significantly (12).

More research is needed to evaluate whether or not threonine was the reason for this adverse effect.

The one medication that has a negative interaction with threonine is memantine (or Namenda), an Alzheimer’s medication (13). If you’re taking this medication, talk to your doctor before adding threonine to your wellness regimen.