Leucine
What Is It?
Alpha amino acids are the building blocks of proteins. The structures of all the alpha amino acids include a carboxylic acid with an amine (NH2) group on the adjacent carbon. The 20 most common amino acids found in proteins are: Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine. The amino acids and simple salts of amino acids, such as Arginine HCl, Calcium Aspartate, Calcium Glycinate, Cysteine HCl, Dipotassium Aspartate, Histidine HCl, Lysine HCl, Magnesium Aspartate, Magnesium Glycinate, Potassium Aspartate, Sodium Aspartate, Sodium Glutamate and Sodium Glycinate may be used in cosmetics and personal care products. Products in which these ingredients may be found include baby products, bath products, cleansing products, eye makeup, shaving preparations and hair and skin care products.
Why Is It Used?
In cosmetics and personal care products, the amino acids function primarily as hair conditioning agents and skin conditioning agents – miscellaneous.
Scientific Facts
Amino acids, normally found in dietary proteinA naturally occurring complex organic substance present in relatively high amounts in meats, fish, eggs, cheese, legumes. Made of carbon, hydrogen, oxygen, and nitrogen, and sometimes sulfur and phosphorus., are released as the protein is digested in the gastrointestinal tract. Eight of the amino acids, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine are considered essential and must be obtained through the diet.
Safety Information
The Food and Drug Administration (FDA) lists the amino acids, including their hydrochloride (HCl), sodium and potassium salts as food additives permitted to be directly added to food. The FDA permits Glycine to be used in Over-the-Counter antacid drug products. The safety of the alpha amino acids and their simple salts has been assessed by the Cosmetic Ingredient ReviewThe Cosmetic Ingredient Review (CIR) was established in 1976 as an independent safety review program for cosmetic ingredients. The CIR Expert Panel consists of independent experts in dermatology, toxicology, pharmacolgy and veterinary medicine. The CIR includes participation by the U.S. Food & Drug Administration and the Consumer Federation of America. (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that these ingredients were safe as used in cosmetics and personal care products.
CIR Safety Review:
The normal presence of these ingredients in the body, and their use as direct food additives led the CIR Expert Panel to focus their review only on dermal irritation and sensitization data. Dermal data on products containing these ingredients indicated that the amino acids are not dermal irritants or sensitizers. The CIR Expert Panel noted that some individuals have issues with dietary Sodium Glutamate and Phenylalanine. The CIR Expert Panel determined that the concentrations of these amino acids used in cosmetic products are lower than levels that would result in significant exposure.
Based on the available data, the CIR Expert Panel concluded that the amino acids and their simple salts are safe for use in cosmetic products.
FDA: Link to Code of Federal Regulations for the amino acids.
- http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?FR…
- http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfCFR/CFRSearch.cfm?FR…
The amino acids and their simple salts may be used in cosmetics and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European UnionUnder the general provisions of the cosmetics regulation of the EU, ingredients appearing on the following function-specific annexes must comply with the listed restrictions and/or specifications: colorants (Annex IV), preservatives (Annex V), UV filters (Annex VI) and other ingredients with specific concentration limits and/or other restrictions (Annex III). Ingredients specifically prohibited from use in cosmetic products are listed in Annex II. Other ingredients listed in the EU cosmetic ingredient database (CosIng) may be used without restrictions..
Link to the EU Cosmetic Regulation: http://europa.eu/legislation_summaries/consumers/product_labelling_and_packaging/co0013_en.htm
More Scientific Information
Bacterial fermentation is the primary method of manufacture used to produce Glutamine, Histidine, Leucine, Isoleucine, Proline, Serine, Arginine, Tryptophan, Phenylalanine, Threonine, Glutamic Acid and Lysine. Enzymatic catalysis is used to produce Alanine, Methionine, Valine and Aspartic Acid, while Glycine chemically synthesized from choroacetic acid and ammonia. Purification after complete hydrolysisDecomposition of a chemical compound into smaller constituents by reaction with water. of proteins is the method used to produce Asparagine and Tyrosine.
Resources
Find out more about the regulation of over-the-counter drugs by the Food and Drug Administration
OTC Drug Home Page: http://www.fda.gov/cder/offices/otc/default.htm
Information about OTC Drug monographs: http://www.fda.gov/AboutFDA/CentersOffices/CDER/ucm106368.htm
Find out more about the regulation of Food Additives by the Food and Drug Administration
Food Ingredients and Packaging: http://www.fda.gov/Food/IngredientsPackagingLabeling/default.htm
Food Contact Substances: http://www.fda.gov/Food/IngredientsPackagingLabeling/PackagingFCS/default.htm
Substances Generally Recognized As Safe (GRAS“GRAS” is an acronym for the phrase Generally Recognized As Safe. Under sections 201(s) and 409 of the Federal Food, Drug, and Cosmetic Act (the Act), any substance that is intentionally added to food is a food additive, that is subject to premarket review and approval by FDA, unless the substance is generally recognized, among qualified experts, as having been adequately shown to be safe under the conditions of its intended use, or unless the use of the substance is otherwise excluded from the definition of a food additive.): http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/default.htm
Search the Code of Federal Regulations http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm
EU Cosmetics Inventory http://ec.europa.eu/consumers/cosmetics/cosing/