Functions of amino acids, benefits of amino acids and amino acid supplements

Home Search Resources Site Map Contact Us
Hair Growth Vitamins

Hair Growth Amino Acids

Hair Enzymes & Hormones

Mineral Health Supplements

Natural Herbal Supplements

Hair Growth Products

Sponsored Articles

Home Hair Amino Acids

Cysteine Para-aminobenzoic-acid Lysine Tryptophan

Role of amino acid supplements for hair growth

Many people ask me what proteins are most appropriate for hair growth. People with hair loss often turn to protein and amino acid supplements as part of their treatment regime. Although it is rare for a lack of protein to be a primary cause of hair loss, there is no harm in taking extra protein or amino acid supplements if you wish. If you take a blood test your serum total protein should be between 60–80 grams per liter. Less than this suggests a problem with protein intake. And you may take some of the protein supplements now available as either as powder protein supplements or liquid protein supplements.

Amino acids and proteins

Protein serves as the major structural component of all cells in the body, and functions as enzymes, in membranes, as transport carriers, and as some hormones. During digestion and absorption dietary proteins are broken down to amino acids, which serve as the building blocks for formation of structural proteins and functional compounds of protein such as enzymes and pre cursors of hormones etc. There are 20 amino acids in all which are required for the synthesis of proteins.

Essential amino acids

But out of which some of the amino acids cannot be synthesized by the body and are therefore are required to be taken as dietary amino acid supplements. The amino acids: Phenylalanine, Valine, Tryptophan, Threonine, Isoleucine, Methionine, Histidine, Arginine, Lysine and Leucine are considered to be essential amino acids. But the distinction between essential and non-essential amino acids is not very clear, as some amino acids can be produced from others. For example the sulfur containing amino acids, methionine and homocysteine, can be converted into each other, but neither can be synthesized de novo in humans. Likewise, cysteine can be synthesized from homocysteine, but not otherwise. So, for convenience, sulfur-containing amino acids are sometimes considered a single pool of nutritionally-equivalent amino acids.

Amino acids & protein for hair growth

Hair follicles require a constant supply of amino acids via the blood stream to maintain hair growth. Hair follicles contain some of the fastest growing and dividing cells in the body so their energy, vitamin, mineral, and amino acid consumption is high. If amino acids are lacking, particularly the essential amino acids listed below, the hair follicles may be less able to produce hair fiber.

Benefits of amino acids

A lack of amino acids in a first world country diet is very unusual and for the most part supplements are not required. However, everyone should ensure they have a healthy, balanced diet that provides all the amino acids required. There are many amino acids, but the nine amino acids which are known as essential amino acids must be provided in the diet and are indispensable amino acids which are required for both hair and other functions of the body. The body can make the other 11 amino acids needed to synthesize specific structures from the nine essential amino acids and carbohydrate precursors.

Protein supplements

Proteins from animal sources, such as meat, poultry, fish, eggs, milk, cheese, and yogurt, provide all nine indispensable amino acids in adequate amounts and for this reason are considered “complete proteins”. Proteins from plants, legumes, grains, nuts, seeds, and vegetables tend to be deficient in one or more of the indispensable amino acids and are called ‘incomplete proteins’. Vegetarian and vegan diets may contain enough protein, but people following these diets may not be receiving all the essential amino acids if they do not pay attention to the type of protein they eat. Vegan diets adequate in total protein content can be “complete” by combining sources of incomplete proteins which lack different indispensable amino acids.

Amino acid function for hair

In terms of hair fiber production, the most important amino acid is cysteine. Cysteine is the most common amino acid in hair. It is particularly important because it contains sulfur molecules. As part of a keratin protein chain, these sulfur molecules cross link with each other to produce disulfide bonds. These chemical bonds are what gives hair its strength. For this reason the most popular amino acid supplement taken for hair is cysteine.

Essential amino acid

Milligrams of amino acid per gram of complete protein (on average)

Histidine

18

Isoleucine

25

Lysine

55

Leucine

51

Methionine & Cysteine

25

Phenylalanine & Tyrosine

47

Threonine

27

Tryptophan

7

Valine

32


Recommended daily allowance of protein by age table


Life Stage Group
RDA of protein per day (in grams)
Infants
0-6 mo
9.1
7-12 mo
13.5
Children
1-3 y
13

4-8 y

19
Males
9-13 y
34

14-18 y
52
19-30 y
56
31-50 y
56
50-70 y
56
> 70 y
56
Females
9-13 y
34
14-18 y
46
19-30 y
46
31-50 y
46
50-70 y
46
> 70 y
46
Pregnancy
= 18 y
71
19-30y
71
31-50 y
71
Lactation
= 18 y
71
19-30y
71
31-50 y
71
19-30 y
46
31-50 y
46
50-70 y
46
> 70 y
46
Pregnancy
= 18 y
71
19-30 y
71
31-50 y
71
Lactation
= 18 y
71
19-30y
71
31-50 y
71

Essential amino acids references:
  • Subcommittees on upper reference levels. Dietary reference intakes for energy, carbohydrate. fiber, fat, fatty acids, cholesterol, protein, and amino acids 2002. National Academy Press, Washington DC, ISBN: 030908525X
  • Scholl D, Langkamp-Henken B, “Nutrient recommendations for wound healing”, J Intraven Nurs, 2001 Mar-Apr;24(2):124-32.
  • Campbell WW, Trappe TA, Wolfe RR, Evans WJ, “The recommended dietary allowance for protein may not be adequate for older people to maintain skeletal muscle” J Gerontol A Biol Sci Med Sci, 2001 Jun;56(6):M373-80.
  • McLarney MJ, Pellett PL, Young VR, “Pattern of amino acid requirements in humans: an interspecies comparison using published amino acid requirement recommendations”, J Nutr. 1996 Jul;126(7):1871-82.
  • Chen J, Gao J, “The Chinese total diet study in 1990. Part II. Nutrients”. J AOAC Int. 1993 Nov-Dec;76(6):1206-13.
  • Williams C, Highley W, Ma EH, Lewis J, Tolbert B, Woullard D, Kirmani S, Chung RA, “Protein, amino acid, and caloric intakes of selected pregnant women”, J Am Diet Assoc, 1981 Jan;78(1):28-35.
  • Acosta PB “Availability of essential amino acids and nitrogen in vegan diets”, Am J Clin Nutr,1988 Sep;48(3 Suppl):868-74.
  • Ahrens EH Jr, Boucher CA, “The composition of a simulated American diet. Comparison of chemical analyses and estimates from food composition tables”, J Am Diet Assoc, 1978 Dec;73(6):613-20.