Glutamine  (L-Glutamine)  is the most abundant and versatile neutral amino acid present in the human body, more precisely an l-α-amino acid and an amide of glutamic acid.

Amino acids together with their salts are used in cosmetics as conditioning agents for both hair and skin (e.g. as moisturisers and other similar functions). Moisturisers are different in nature: the best are the natural ones that exploit the mechanism of integration between the ingredient and the skin by moisturising the horny hydrolipid film, i.e. the thin protective layer that covers the epidermis protecting it from harmful external microbes, keeping the skin moisturised and supple and its pH or acidity value between 4 and 6.  Then there are the occlusive moisturisers, usually derived from petroleum (Paraffinum, Paraffinum liquidum and others), but also triglycerides, lanolin oil, natural or synthetic waxes, fatty acid esters and others that create an artificial occlusive layer on the stratum corneum of the skin with the advantage of accelerating the protective process but with the disadvantage of preventing the skin's natural transpiration.

α-amino acids that have similar physical structures undergo similar changes with regard to solubility in water/ethanol mixtures, and technologies to separate α-amino acids from industrial residues, which may not even be innocuous, are constantly being improved. However, many data on the solubility in water-ethanol and ethanol of some α-amino acids are contradictory or even lacking, and the effects of ethanol on the solubility of amino acids may be different. Overall, the scientific literature considers that α-amino acids do not pose significant problems for human health when taken orally, except in people with certain genetic diseases.

Food safety: amino acid α is generally considered safe.

Cosmetic safety: amino acid α is generally considered safe when formulated to be non-irritant.

It is presented industrially in the form of a white crystalline powder, odourless and slightly sweet.

Unstable in neutral solution, it decomposes easily.

What it is used for and where

Medical

Glutamine, a non-essential amino acid, is a useful nutritional supplement in pre- and post-operative patients as it acts in the metabolism of the most important organs of the human body: liver, intestine, skeletal muscles.

Amino acids play a key metabolic function in the human body and are constituents of proteins. 

Nutritional supplementation with glutamine is used by sportsmen and women because, due to its immunomodulatory role, it can help improve certain fatigue parameters (1).

Cosmetics

It is included in personal care creams and is used as a skin conditioning nourishing agent.

Food

As food additives they perform different functions: preservatives, flavour enhancers, food supplements and more.

For more information: 

  Glutamine studies

Typical commercial product characteristics Glutamine

• Molecular Formula  C₅H₁₀N₂O₃
• Linear Formula    H₂NCOCH₂CH₂CH(NH₂)CO₂H
• Molecular Weight    146.14
• Exact Mass   146.069138
• CAS  56-85-9
• UNII    0RH81L854J
• EC Number   200-292-1    230-006-0
• DSSTox Substance ID  DTXSID1023100
• IUPAC  (2S)-2,5-diamino-5-oxopentanoic acid
• InChI=1S/C5H10N2O3/c6-3(5(9)10)1-2-4(7)8/h3H,1-2,6H2,(H2,7,8)(H,9,10)/t3-/m0/s1
• InChl Key      ZDXPYRJPNDTMRX-VKHMYHEASA-N
• SMILES   C(CC(=O)N)C(C(=O)O)N
• MDL number  MFCD00008044
• PubChem Substance ID    24895342
• ChEBI  18050
• eCl@ss    32160406
• Beilstein    1723797
• JECFA    1430   
• NACRES  NA.26
• FEMA   3684
• NSC   760081    759628
• RTECS   MA2275100
• RXCUI   4885  
• NCI   C522

Synonyms

• Levoglutamide
• L-Glutamic acid 5-amide
• (S)-2,5-Diamino-5-oxopentanoic acid

References________________________________________________________________________

(1) Coqueiro AY, Rogero MM, Tirapegui J. Glutamine as an Anti-Fatigue Amino Acid in Sports Nutrition. Nutrients. 2019 Apr 17;11(4):863. doi: 10.3390/nu11040863.