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Amino Acids: Definitions and Benefits

Understand the difference between these essential dietary and nonessential amino acids and how they can benefit you.

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Thanks to Robert Atkins, MD, protein moved from the exclusive lexicon of nutritionists to part of our daily vocabulary. And yet protein isn’t just about managing your weight. Much of the tissue that makes up your body-skin, fingernails, organs, bone, and even the tip of your nose-consists of this remarkable substance. It’s no surprise then that nutritional biochemists consider protein to be the workhorse of the body.

But there’s much more to what we know as protein. It consists of chemical building blocks called amino acids, and these substances do the real work. When you eat protein, your digestive tract breaks it down into amino acids, which are subsequently used individually or restructured into new proteins or related molecules called peptides.

Some amino acids are considered essential dietary nutrients because your body cannot make them, and the only way you get them is through your diet. Others have been termed nonessential because the body can make them on its own. But the word nonessential is a misnomer, because many people do not make these amino acids very efficiently under some circumstances. These are termed conditionally essential. One other noteworthy point: The names of most amino acids are preceded with an “L,” such as L-leucine, which denotes their leftward molecular rotation, but this prefix is often dropped in common usage. (So “leucine” and “L-leucine” are the same thing.)

Blood Sugar Regulators – Several amino acids have a beneficial effect on blood sugar apart from their role in protein, including:


Large supplemental dosages of glycine can reduce blood sugar levels in both healthy people and those with diabetes, according to research that dates back to 1932. It works by accelerating the burning of blood sugar. In a study at the University of Minnesota, Minneapolis, researchers found that 3.6-5.4 grams of glycine daily reduced post-meal increases in blood sugar by 15 percent.


Glutamine supplements can often reduce sugar cravings. Doctors compared the effects of 15 and 30 grams of L-glutamine to a blood-sugar lowering drug called sitagliptin. The 30-gram dose of L-glutamine led to the best responses among people with type 2 diabetes. L-glutamine dampened the post-meal rise in glucose and insulin.


Some evidence indicates that taurine plays a role in regulating blood sugar, and it might help prevent metabolic syndrome, a prediabetic condition. Taurine is an “inhibiting” neurotransmitter, meaning that it counters the activity of stimulating neurotransmitters and has a calming effect. It’s typically taken as 750 mg one to two times daily between meals.

Immune Boosters – Two amino acids, N-acetylcysteine and lysine, can enhance immune function and help fight infections:

N-Acetylcysteine (NAC)

The preferred form of L-cysteine, NAC is a building block of glutathione, a potent antioxidant and detoxifier made by the liver. NAC can significantly reduce flu and cold symptoms if taken right after symptoms appear. It also appears to have positive effects on mood and behavior, possibly by regulating some neurotransmitters. A recent study reported that NAC reduced irritability and repetitive behavior in children with autism. Other research has found that NAC supplements can reduce obsessive-compulsive and self-destructive behavior patterns, as well as cravings for cocaine. Take 500-1,800 mg daily.


Several studies have found that lysine is helpful in reducing or shortening outbreaks of oral and genital herpes infections. It works by inhibiting the reproduction of viruses, so it might also be helpful in fighting colds and flu. When taking lysine supplements, try to avoid arginine, another amino acid that can suppress lysine activity. Try 500-1,000 mg of lysine daily.

Mood Enhancers – Individual amino acids can have a positive effect on mood, especially when it comes to reducing anxiety and supporting a calm attitude:


Tryptophan and its 5-hydroxytryptophan (5-HTP) form are precursors to serotonin, an important calming neurotransmitter. So low intake of tryptophan reduces serotonin production in the brain. Tryptophan supplements have benefits in depression, anxiety, and insomnia.

What’s the difference between tryptophan and 5-HTP? First, the body converts tryptophan to 5-HTP. Second, tryptophan functions in multiple biochemical pathways, including serotonin production, but 5-HTP can only be used in the production of serotonin. For anxiety, depression, or restless sleep, take 50-150 mg of 5-HTP twice daily, with the last dose 30-60 minutes before bedtime. For tryptophan, take 500- 1,500 mg before bed. With either form, start by trying the lower end of the dosage range. 5-HTP can cause transient nausea.


This amino acid is found in large quantities in quality green and black teas. The more theanine in tea, the better its taste, and usually the higher the price. Theanine supplements boost brain levels of alpha waves, reducing anxiety, promoting a sense of relaxation, and improving mental sharpness. A study of college students found that theanine supplements significantly eased feelings of stress during exams. Try 200 mg up to four times daily.


Short for gamma amino butyric acid, GABA is both an amino acid and neurotransmitter. Like theanine, it helps people maintain mental focus, and the two supplements work well together. Although GABA helps the brain filter out distractions, while allowing important information to be processed, it usually does not cross the blood/brain barrier. People with anxiety, panic attacks, insomnia, epilepsy, and schizophrenia may respond to GABA supplementation. Try 500-1,000 mg one or two times daily.

Muscle Builders for Seniors – After age 30, people lose roughly one- third of a pound of muscle annually, and the rate of muscle loss accelerates each decade after age 50. Such muscle loss can lead to frailty in seniors. Resistance training with weights can slow this loss, and certain supplements can also help preserve muscle.

Branched chain amino acids (BCAAs)

BCAAs consist of three amino acids-leucine, isoleucine, and valine-that are crucial for muscle production. They’re often used by body builders, but you don’t have to be a weight lifter to benefit. Of the three BCAAs, leucine is the most important. In one study, researchers found that leucine supplements (3 grams daily) helped increase muscle synthesis in older men almost to the same level as in young men. Meanwhile, another study, published in Clinical Nutrition, found that leucine increased muscle even when combined with a low-protein diet.


These two amino acids can help fight fatigue. In one study, researchers asked 26 middle-aged and elderly people to take either beta-alanine supplements (800 mg, three times daily) or placebos for 90 days. The supplements led to a 28 percent improvement in endurance and greater resistance to fatigue.

Multi Aminos

Muscle is made largely of protein, and multi amino acid supplements can boost muscle mass and strength. The effect is most significant in seniors, but middle-aged and younger people can also benefit from multi amino acid supplements, most of which provide about 10 grams of a blend of at least eight amino acids. In a study of seniors, reported in the American Journal of Cardiology, daily multi amino acid supplements led to significant increases in muscle after six months-and even more muscle after 16 months.

Pain Relief – One amino acid stands out for its benefits in easing pain:

DL-Phenylalanine (DLPA)

This amino acid contains both the “left” and “right” forms of phenylalanine. DLPA is especially helpful in reducing chronic pain, such as in arthritis and low back pain, and it enhances the effects of other analgesics. The L form does not help with pain, but the D form does, most likely by increasing the body’s production of endorphins. D-phenylalanine supplements are hard to find, and the DL-phenylalanine form is an excellent substitute. Interestingly, people can often reduce the dosage over time. Try 1,000-3,000 mg of DLPA one or two times daily.

Improving Sexual Function – One amino acid is crucial for male sexual function and may also be involved in sexual arousal in women:


This amino acid serves as the precursor to nitric oxide, a molecule that regulates blood vessel tone and flexibility. (Nitric oxide is different from nitrous oxide, also known as laughing gas.) By way of nitric oxide, arginine regulates the endothelium, a thin layer of cells in blood vessel walls. The endothelium gently expands and contracts, helping the heart move blood throughout the body. Supplemental arginine can help improve endothelial function in people with heart disease, and it might also lower blood pressure.

The same ability to dilate blood vessels, allowing blood to temporarily pool, is necessary for an erection in men. Supplemental arginine has been shown to improve the ability of blood vessels in the penis to dilate, resulting in firmer erections. The benefits may be enhanced by combining arginine with Pycnogenol, a natural antioxidant. Try 1,000-3,000 mg of arginine daily along with 150 mg of Pycnogenol.

How to Take Amino Acids

When you take individual amino acid supplements, do not take them with food, because the amino acids in your food will compete with those in your supplements and reduce their absorption. As a general rule, take amino acid supplements at least 30 minutes before consuming anything (except for water) and two hours after eating.

Amino Acid Supplements

Bluebonnet Nutrition – Amino Acid Capsules, ideal for seniors who want to maintain everyday muscle strength, feature a broad spectrum of amino acids.

Carlson Labs – Healthy Mood 5-HTP Elite promotes feelings of well-being by enhancing the production of the neurotransmitter serotonin.

Quantum Health – Super Lysine+ Immune Health blends immune-boosting olive leaf, astragalus, and L-lysine for powerful defense against bugs.

ReNew Life – Crave Be Gone chewable tablets help to keep blood sugar levels stable with L-glutamine, serotonin-boosting 5-HTP, and cinnamon bark extract.

Solgar – L-Arginine 1,000 mg provides a highly bioavailable form of L-arginine, known to stimulate nitric oxide for enhanced circulatory function-including blood flow to the sexual organs.

Terry Naturally – Curamin relieves pain with an all-natural, clinically proven formula that includes DLPA and curcumin, a powerful anti-inflammatory spice.