Guide to Amino Acids
Guide to Amino Acids

Amino acids are the foundation for all life on Earth. As the molecular building blocks of proteins, they’re necessary for many essential life functions. Comprised primarily of carbon, hydrogen, nitrogen and oxygen, amino acids assemble in various sequences to create different proteins. In addition to their essentiality in the assembly of proteins for both collagen and muscle tissue, amino acids play an integral role in a wide range of bodily functions. They’re required for the production of certain neurotransmitters, as well as enzymes for the digestion of foods and many other biochemical processes including tissue repair, detoxification, the production of genetic material and hormones, and much, much more. Amino acids and the proteins they comprise account for approximately 75% of the human body’s dry weight..

Despite the almost infinite number of variations possible, and the more than 500 classified amino acids, all organisms on Earth rely on the same 20 amino acids for life. All amino acids begin with a “backbone” consisting of a central carbon atom (C), an amine group (-NH2), a carboxyl group (-COOH), and a hydrogen atom. Any subsequent atoms or groups are called side chains, or R groups. These side chains determine the individual identity of each amino acid. Single amino acids are then linked into peptides and assembled into various structures to form proteins.

There are actually 22 common amino acids that are incorporated into proteins, but only 20 of these are encoded by the universal genetic code. The other two (selenocysteine and pyrrolysine) are only incorporated into proteins via unique mechanisms. These 20 amino acids are grouped into three categories – essential, non-essential, and conditionally essential.

More topics covered in this guide include:

  • Essential Amino Acids
  • Non-Essential Amino Acids
  • Conditionally Essential Amino Acids
  • Branched Chain Amino Acids
  • Free-Form Amino Acids
  • Other Amino Acids of Nutritional Value

NOW® is the clear #1 brand in the amino acid category (SPINSscan Natural data 2016). We carry a comprehensive variety of amino acid supplements in capsule, vegetable capsule, tablet, liquid and powder forms for your convenience. NOW uses only the natural “L” form of amino acids and no “D” or “DL” synthetic forms. Aside from some of our combination amino acid supplements, NOW amino acids are bioavailable free-form aminos.


amino acid guide preview
Guide to Amino Acids