Glycine
Simplest NMF amino acid – a humectant and pH buffer. Pregnancy-safe.
Evidence by route
Topical application
NMF amino acid. Humectant with confirmed role in hydration.
- Rawlings AV, Harding CR. Moisturization and skin barrier function. Dermatol Ther 2004. PMID 14728698
How to read tiers A–F
- BLimited evidence. One RCT or several controlled studies with limitations
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Glycine is the simplest amino acid, without a chiral center. It is essential for protein synthesis, collagen, and glutathione. In skin, glycine is part of the natural moisturizing factor (NMF) of the stratum corneum and holds water in the upper epidermis. In type I, II, and III collagen, every third amino acid in the primary structure is glycine, which makes the triple-helix folding of the molecule possible. Where it is used. Serums and toners for dehydrated skin, barrier recovery, post-retinoid or post-acid care, amino acid complexes, and gentle eye-area products. Concentrations 0.5-3%. In Spain: Sesderma Reti Age, Cantabria Endocare Hydractive, Mesoestetic Hyaluronic Serum. Mechanism. Humectant – binds water molecules through phosphate and amine groups, raising stratum corneum hydration by 8-15% over 2-4 weeks. Maintains physiological pH through buffering. Provides substrate for glutathione (the main endogenous skin antioxidant) and collagen synthesis. Combined with proline, lysine, and arginine, glycine acts as an amino acid barrier-repair complex. Evidence base. Glycine-containing NMF complexes have evidence base B-C through indirect data on NMF generally (Verdier-Sevrain 2007 for hydration, Choi 2007 for amino acid blends in atopic dermatitis). Isolated clinical trials of topical glycine are rare. Safety. Pregnancy and breastfeeding – topical use is safe without restriction. Non-comedogenic, non-sensitizing, hypoallergenic. CIR (2018) confirmed safety for all skin types, including sensitive and reactive. Practical notes. Glycine usually appears within an amino acid complex alongside other NMF components (sodium PCA, urea, serine, alanine). On its own it provides mild moisturization without strong active load. Compatible with every cosmetic ingredient. A reasonable option for patients with impaired barrier, atopy, or post-procedure skin.
Frequently asked questions
Is Glycine safe during pregnancy?
Glycine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Glycine for?
Glycine suits: normal, dry, combination, oily, sensitive.
What is Glycine and what does it do in cosmetics?
Simplest NMF amino acid – a humectant and pH buffer.
Is Glycine comedogenic?
On the Fulton scale 0/5 – non-comedogenic. For acne-prone skin, a rating of 3 or higher suggests choosing an alternative.
What's the INCI name for Glycine?
The INCI name is Glycine. It may also appear as: Aminoacetic Acid.
See Glycine in a product composition right on the store page
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