Types of Amino Acids

The molecular building blocks of protein

Amino acids are essential for many basic life and body functions.*

Amino acids are essential in the assembly of proteins for both collagen and muscle tissue.* They are required for the production of certain neurotransmitters and enzymes for the digestion of foods and other biochemical processes including detoxification. They are required for the production of genetic materials and hormones and so much more.*

Did you know? Amino acids and the proteins they comprise account for approximately 75% of the human body’s dry weight.

Types of amino acids

Despite over 500 known amino acids, with an infinite number of possible variations, there are only 20 amino acids deemed necessary for human health. These amino acids are grouped into three categories: essential, non-essential, and conditionally essential.

Some amino acids can also be classified as branched-chain amino acids, as well as other amino acids of nutritional value that don’t neatly fit into these other categories.

Essential amino acids are those that the human body cannot synthesize (produce) on its own; they’re always obtained from the diet, without exception. There are nine essential amino acids – histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. A recommended daily allowance (RDA) of about 15,000 mg per day has been established by the National Academy of Sciences for adults 19 and older.
Non-essential amino acids can be assembled or synthesized by the human body from ingested materials and do not need to be obtained from the diet. There are four non-essential amino acids – alanine, asparagine, aspartic acid, and glutamic acid.
Normally your body is capable of producing conditionally essential amino acids and doesn’t need to obtain them from your diet. However, in certain stressful situations, the body requires higher levels of these amino acids and obtains them from your diet. You may see these amino acids also referred to as conditionally non-essential, but they’re one and the same. There are seven conditionally essential amino acids – arginine, cysteine, glutamine, tyrosine, glycine, proline, and serine.
The essential amino acids leucine, isoleucine and valine collectively are referred to as the branched-chain amino acids (BCAAs).This amino acid group accounts for approximately 35% of the essential amino acids in muscle proteins, with 40% required from a healthy diet. They’re critical for muscle protein synthesis and they support normal muscle repair processes.*
Free-form amino acids refer to single amino acids that are already in a pre-digested form and ready to be used by your body. Some nutritional products, especially amino acid blends, contain whole proteins and large peptides (chains of amino acids), which the body must first break down into smaller peptides and individual amino acids before use. For faster utilization and better bioavailability, look for free-form amino acids.

There are several amino acids, peptides and amino acid-like nutrients that support various body systems, including L-Carnitine, N-Acetyl-Cysteine (NAC), Citrulline, Glutathione, and others.*

Can’t get enough info about amino acids?

Download our Guide to Amino Acids

Try amino acid powders for sports nutrition

Need your amino acids but don’t relish the thought of popping mass quantities of capsules and tablets, or choking down giant pills? You’re definitely not alone. No worries, an amino acid powder is just what the trainer ordered.

A powdered amino acid is a pure powder that is quickly absorbed by the body. Unlike tablets or capsules, amino acid powders don’t need to be broken down and are more easily absorbed by your body. They’re more readily available for use and go to work more quickly.
Amino acid supplements in powdered form are easily added to your favorite workout beverage or protein shake.
Individuals with compromised digestive function or those on restricted diets may have a hard time obtaining amino acids from food and pills. Our amino acid products labeled as "Pure Powder" contain no added fillers or excipients.

All your aminos in one supplement

Do you prefer convenience without sacrificing content or quality? You just need one supplement that covers all the bases.

NOW^® Sports Amino Complete™ is a unique combination of amino acids and protein:

Effective, proprietary blend of peptide-bound amino acid sources (whey protein isolate, soy protein isolate, sodium caseinate, and gelatin), plus free-form amino acids (L-glutamine, L-arginine, and L-ornithine).
Added vitamin B-6 from pyridoxine HCl for its crucial role in amino acid metabolism.*
All 20 common amino acids including essential, non-essential and branched-chain amino acids.

All NOW^® Sports Amino Acid products and NOW^® Supplements Amino Acid products are carefully screened for purity and potency and are manufactured with our industry-leading quality assurance procedures.

The Benefits of Amino Acids

Amino Acid	Main Benefit	Additional Benefits
5-HTP	Neurotransmitter Support*	Supports Positive Mood*
Acetyl-L-Carnitine	Brain and Nerve Cell Function*	Transports Fatty Acids* Cellular Energy Production*
GABA	Neurotransmitter Support*	May Help Promote Relaxation & Ease Nervous Tension*
Glutathione	Free Radical Neutralizer*	Detoxification Support*
Glycine	Neurotransmitter Support*	Promotes Restful Sleep* Nervous System Support*
L-Arginine	Amino Acid	Nitric Oxide Precursor*
L-Carnitine	Fitness Support*	Cellular Energy Production* Transports Fatty Acids*
L-Carnosine	Healthy Aging*	Supports Muscle Vitality* Free Radical Scavenger*
L-Citrulline	Supports Protein Metabolism*	Healthy Immune System Function*
L-Cysteine	Structural Support*	Healthy Skin, Hair and Nails*
L-Histidine	Essential Amino Acid	Critical for Normal Brain Function* Immune System Support*
L-Lysine	Essential Amino Acid	Supports Collagen Synthesis* Healthy Immune Function*
L-Methionine	Essential Amino Acid	Supports Detox Mechanisms*
L-Ornithine	Fitness Amino Acid*	Healthy Protein Metabolism*
L-Phenylalanine	Nervous System Support*	Healthy Nervous System*
L-Proline	Structural Support*	Necessary for Collagen Production*
L-Theanine	Tension Management*	Promotes Relaxation* Healthy Vascular Function*
L-Tryptophan	Supports Relaxation*	Encourages Positive Mood* Promotes Restful Sleep*
L-Tyrosine	Neurotransmitter Support*	Healthy Glandular Function* Supports Mental Alertness*
NAC	Free Radical Protection*	Immune System Support* Supports Liver Health*
SAMe	Nervous System Support*	Supports Joint Health*
Taurine	Nervous System Health*	Healthy Visual Function*

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.