Hyaluronic Acid

Hyaluronic acid (HA; sold as its salt, sodium hyaluronate, CAS 9067-32-7) is an unbranched, non-sulfated glycosaminoglycan composed of repeating D-glucuronic acid / N-acetyl-D-glucosamine disaccharide units. It is not a peptide at all — it has neither an amino acid backbone nor a peptide bond. It is listed in peptide catalogues because skin and joint research routinely uses it as a co-formulant and as a comparator.

Molecular weight decides the biology

In tissue, native HA may be larger than 1 MDa, and the length of the chain alters its biological behaviour, not merely its viscosity. High-molecular-weight HA is usually described as space-filling, water-retaining and anti-inflammatory; smaller chains and oligosaccharide fragments produced by hyaluronidase or oxidative cleavage are reported to be pro-inflammatory and pro-angiogenic via CD44 and TLR2/4. For research purposes a specification reading simply "hyaluronic acid" is therefore not enough — the MW range should be stated on the certificate of analysis.

Handling tips: HA takes up moisture very readily, dissolves slowly and is best left to hydrate without aggressive shearing; its solutions are thick enough to compromise pipetting accuracy. Heat, acidic pH and free radicals all break it down.

Related terms and material

PDRN · molecular weight (Da) · hydrophilic. Reference material: Hyaluronic Acid (5 mg lyophilized or 2 mL 1% solution), cosmetic peptides. Further reading: what is hyaluronic acid.