Categorizing the Building Blocks of Life
This section provides some of the hard data gained from decades of research on amino acids. If you find this section too "scientific," "bookish," or just not practical enough in terms of your immediate health concerns, click here to go to the sub-site describing the action of all 22 amino acids.

Most textbooks will tell you that there are 20 amino acids. However, there are actually hundreds of them, some of them short-lived, some of them modifications of the main 20. We will call those the "minor amino acids." For example, Serine is counted as one of the main 20, but phosphoserine, another important amino acid, is never classified among the major 20 and is a minor amino acid.

Classifying amino acids helps us break them down into smaller byte-size pieces so that we can better mentally ingest them. When we mentally understand amino acids, it becomes obvious why one should not just mentally ingest them, but should take them by mouth in order to enhance our energy, concentration, performance... and help us recover from illness, whether acute or chronic. Here are 6 different ways to categorize amino acids:

I - Essential Versus Non Essential

Essential Amino Acids
(You must include them in your diet because your body can't make them on its own. If you don't ingest them, you will not be experiencing optimal health and may have a disease caused by that deficiency.)
Arginine
Histidine
Methionine
Threonine
Valine
Isoleucine
Lysine
Phenylalanine
Tryptophan
Leucine

Non-Essential Amino Acids
(Under normal conditions, your body can manufacture these amino acids, so you don't have to ingest each of these).
Alanine
Asparagine
Aspartic Acid
Cysteine
Glutamine
Glutamic Acid
Glycine
Proline
Serine
Tyrosine

Conditionally Essential
(If your system is stressed, out of balance, or diseased, these amino acids become essential and you must get them from food or supplements).
Arginine
Glycine
Cystine
Tyrosine
Proline
Glutamine
Taurine

Essential amino acids are considered to be ones that we must ingest, while non-essential have historically been believed to be produced inside our bodies. In other words, it has been felt that we do not need to supplement our diet with non-essential amino acids.

This thinking does not hold up well in the light of actual, clinical experience. When we are suffering from a moderate to severe chronic illness, we lose the ability to manufacture enough non-essential amino acids, and thus require supplementation. Problems with digestion will also necessitate supplementation of "non-essential" amino acids. Most people have been told that if you eat a balanced diet, you'll get all the amino acids you need. That simply is not true if you are significantly out of balance. For example, if your amino acid testing reveals a significantly low Tryptophan, you will have to eat several turkeys a day... or gallons of milk to get enough Tryptophan from a natural source. Recent research has led to a third category within this classification system, namely, "Conditionally Essential." These amino acids are normally non-essential, but become essential during times of physiological stress.

II - Classification According to Charge and Polarity of Side Chains (R-Group)

III - Glycogenic and/or Ketogenic

IV - Proteogenic Versus Non-Proteogenic

The 40,000 different kinds of protein in the human body are made up of 20 amino acids.
Before we list the amino acids in these 2 groups, let's cover the vast role that proteins play:
1. Enzymes
2. Structural protein — collagen and connective tissue
3. Contractile proteins — muscle tissue.
4. Transport proteins — hemoglobin
5. Immune proteins — immunoglobulins
6. Regulatory proteins — hormones

Essential Proteogenic (protein-producing) Amino Acids
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine

Non-Essential Proteogenic (protein-producing) Amino Acids
Alanine
Arginine
Aspartic Acid
Asparagine
Cysteine
Glutamic Acid
Glutamine
Proline
Serine
Tyrosine

Non-Proteogenic Amino Acids
The non-proteogenic amino acids are generally metabolites or analogues of the proteogenic amino acids:
Ornithine, a minor amino acid is made from Arginine.
Taurine is made from methionine and cysteine.
Hydroxyproline and Hydroxylysine, both minor amino acids, are made from proline and lysine.

V - Amino Acids by Structure

Amino acids can be grouped according to the structure of the side chains, or the R-Group.

This graphic illustrates the molecular structure of amino acids.

Here is what each of the letters inside the spheres stands for: C = Carbon O = Oxygen N = Nitrogen H = Hydrogen R = We'll get to that in a minute.

Every amino acid has this basic structure with a positive charge at one end and a negative charge at the other.

"R" is the part of the amino acid molecules that differs from one amino acid to another.

Note that the bond between one atom and another is cone-shaped for most of the molecule. This cone shape represents the fact that the 2 atoms connected by the cone-shape are in flux. The distance is not a fixed, unbending figure, but is more a probability. The bond between carbon and nitrogen is a straight line, indicating less flexibility in the bond, and a distance that is more fixed.

The amino acid structure gives us some clues about life and death. Remember that amino acids account for 75% of the body's dry weight. After death (and after either burial or cremation), we slowly return to the elements. As the amino acid bonds break down, oxygen, nitrogen, and hydrogen become gases that return to the atmosphere, leaving only carbon behind. Thus "dust to dust" is better understood in light of amino acid structure. Only carbon and other minerals remain.

One might say that in life, and in the birth of life... oxygen, hydrogen, and nitrogen (the primary elements of Earth's atmosphere) come together, along with carbon, to form the organized system known as "Life."

VI - Amino Acid Functions

For the clinician (or educated healthcare consumer) understanding amino acids according to their functions is the most useful approach, and leads directly to recommendations for supplementation. In this section, you will notice more than the usual 20 amino acids, for this grouping includes a number of the lessor-known amino acids. Also notice that a particular amino acid may appear in more than one category. For example Glutamine is categorized as a Neurotransmitter, Glycogenic, and Branched Chain Amino Acid. This "Functional" way of understanding and classifying amino acids builds on the "Glycogenic Versus Ketogenic" system and greatly amplifies and clarifies amino acid functions.

Neurotransmitter Amino Acids
Abnormalities in this group are widespread in their implications, and are seen in virtually all mental/emotional problems, primary brain problems (stroke, Alzheimer's Disease, epilepsy), depression, anxiety, insomnia, poor concentration, memory problems, and mental exhaustion. Aspartic Acid
Asparagine
Gamma Amino Butyric Acid (GABA) (minor amino acid)
Glutamic Acid
Glutamine
Glycine
Phenylalanine
Taurine
Tryptophan
Tyrosine

Branched Chain Amino Acids (BCAA)
This group contributes to protein synthesis. Surgery, Deficiencies are associated with injury, exercise, and muscle wasting. With Chronic Fatigue Syndrome (CFS), one usually sees deficiencies in this group, which relates to easy fatiguability, and post-exertional exhaustion.
Glutamine
Isoleucine
Leucine
Valine

Sulfur-Containing Amino Acids
Deficiencies in this group are associated with food allergies and chemical sensitivity. Cystine/Cysteine
Methionine
Taurine

Glycogenic Amino Acids
Deficiencies in this group are associated with problems with sugar metabolism, diabetes mellitus, hypoglycemia, candidiasis, poor concentration, abnormalities in zinc and/or chromium levels, and fatigue.
Alanine
Glutamine
Glycine
Serine
Threonine 

Urea Cycle Amino Acids
Deficiencies in this group can be associated with liver disease, kidney disease, or strenuous exercise.
Arginine
Aspartic Acid
Citrulline (minor amino acid)
Ornithine (minor amino acid)

Connective Tissue Amino Acids
Abnormalities within this group are associated with trauma, surgery, muscle wasting, and strenuous exercise.
Hydroxyproline (minor amino acid)
Hydroxylysine (minor amino acid)
Proline

Amino Acids that Give Clues about Non-Amino Acid Deficiencies
Phosphoserine (minor amino acid)
Elevated blood levels of Phosphoserine is predictive of a deficiency of pyridoxal-5-phosphate (P5P), a critical form of vitamin B-6. Without adequate blood levels of P5P, many amino acid reactions become impaired. In particular, tyrosine cannot be converted to norepinephrine without P5P, and tryptophan cannot be converted into serotonin.

Histidine
Abnormally high levels of histidine are associated with abnormally low levels of zinc, and vice versa.

Taurine
Abnormally low levels of taurine are suggestive of vitamin B12 deficiency, zinc deficiency, and vitamin A deficiency. With low taurine levels, one should do extra lab work to evaluate B 12, vitamin A, and zinc.

Arginine (deficiency indicates a weakened immune system).
Histidine (deficiency is associated with auto-immune disease)
Lysine (deficiency is suggestive of viral infection).
Taurine (deficiency is suggestive of generalized candidiasis)
Threonine (deficiency is associated with AIDS).

This web site goes into detailed description of the 20 "primary" amino acids as well as many of the "secondary" or "minor amino acids." Click here for those detailed descriptions so that you can better understand the powerful role amino acids play in your life. You can begin to examine your own life, your state of wellness, or illness by understanding what these building blocks of life do.