Safe Duration of Taking Amino Acid Supplements

Amino acids are chemicals that are crucial to human nutrition because they act as the building blocks of protein and aid in metabolism. There are nine essential amino acids you must eat in your daily diet for proper health, according to the Institute of Medicine. Amino acid supplementation is not proven safe or beneficial beyond your daily intake requirement, and you should only take such supplements as long as your doctor advises you to do so.

A woman is preparing a snack next to her workout supplements. (Image: gpointstudio/iStock/Getty Images)

Average Protein Consumption

You consume the amino acids every day through dietary protein sources. Animal-based foods like meats, milk and eggs contain all of the nine essential amino acids, as well as many nonessential amino acids. The World Health Organization states that the average daily protein intake in developed nations is around 3 g per kilogram of body weight from diet plus an additional 1 g per kilogram of body weight from amino acid or protein supplements. This is well beyond the daily protein requirement for sedentary adults, which is only 0.8 g per kilogram of body weight daily. Taking an amino acid supplement on top of your dietary intake is unlikely to give you any sort of health benefit.

Defining Your Needs

Determining if you need to take an amino acid supplement, and how long you should take said supplement is a complex process that you should not attempt to diagnose without obtaining the professional medical opinion of your doctor. Your age, current state of kidney function, body composition, physical activity level and dietary intake of the lacking amino acid can all affect how long you should continue taking a supplement.

Side Effects

Studies of excess amino acid intake over long periods of time have yielded inconclusive results regarding the potential effects of such a diet. People with reduced kidney function should likely avoid taking amino acid supplements at all beyond their daily requirement because this can further degrade kidney operation and possibly result in kidney failure. If you experience any unintended side effects, such as diarrhea, you should discontinue supplementation immediately. Each amino acid is different, however, and some may be safer than others. For example, your doctor may prescribe an L-arginine supplement as a way to lower your blood pressure. Once you obtain the desired effect of lowered blood pressure, it is safest to return your arginine intake to pre-supplementation levels.

Toxicity

Some amino acids may not be safe to take for any duration of time due to the negative impact they can have on your body. University of Milan professor Francesco Dioguardi states that diets high in the amino acid methionine may lead to stunted growth, oxidative damage to your cells and cardiovascular disease. He adds that chronic arginine and glutamine supplementation may limit your body's ability to synthesize these nonessential amino acids on its own. If you have the birth defect phenyketonuria, your body cannot metabolize the amino phenylalanine, and any supplementation of phenylalanine can contribute to brain damage.