Hyaluronic acid

Hyaluronic acid grades and forms

Hyaluronic acid for food supplements is bought as a powder, usually as its sodium salt, sodium hyaluronate. The choice of grade rests on three points: production route, molecular weight and the basis on which content is declared.

Hyaluronic acid is a polysaccharide made of repeating units of glucuronic acid and N-acetylglucosamine. Chain length varies from batch to batch and grade to grade, which is why no single formula applies. Commercial material comes either from microbial fermentation or from extraction of animal tissue, typically rooster combs. The route matters for vegetarian positioning and for the origin information a brand needs to hold.

Molecular weight is the main grade attribute. Grades are offered as high, medium or low molecular weight, and hydrolysed grades are broken down further. Molecular weight sets solution viscosity and so decides how the powder handles. The specification sheet states the molecular weight range, assay, loss on drying and microbiological limits. SoleChem sends it, with the certificate of analysis, alongside the quote.

Check whether the assay is expressed as sodium hyaluronate or as hyaluronic acid. The two bases give different figures for the same material, and the label must use the same basis as your calculation. The sodium salt is often registered under its own CAS number, so confirm which identity the specification sheet uses. Ask for the grade and molecular weight you need in the quote form.

EU regulatory status

Hyaluronic acid is neither a vitamin nor a mineral. It therefore falls outside Annexes I and II of Directive 2002/46/EC, which list the vitamins and minerals and their permitted forms. Its use in food supplements is governed by national rules on other substances, which are not harmonised across the EU.

Member states handle these substances differently. Some require notification before sale, some keep lists of accepted substances and some set maximum amounts. Check the rules of each target market with its competent authority.

Regulation (EC) No 1925/2006 includes a procedure for restricting or prohibiting certain other substances added to foods. Confirm that no measure under it applies to hyaluronic acid before launch.

Novel food status under Regulation (EU) 2015/2283 can depend on source, production route and use before 15 May 1997. Check the specific grade, including hydrolysed or low-molecular-weight material, against the Union list of novel foods. The guide to novel food status explains the process.

Any claim on the label must comply with Regulation (EC) No 1924/2006. Check the EU Register of nutrition and health claims and the health-claims guide before drafting label text.

Formulation notes

Hyaluronic acid powder is hygroscopic. Keep containers sealed and dispense in controlled humidity, since moisture uptake causes caking and weighing errors. In water it hydrates to viscous solutions even at low concentrations, and viscosity rises with molecular weight.

• Capsules. Where the label claim is small relative to the fill, blend uniformity is the main risk. Pre-blend with a diluent and add a flow aid such as silicon dioxide. Shells of HPMC or gelatin both suit a dry fill. See ingredients for capsules.
• Tablets. High-molecular-weight grades can make wet granulation hard to control. Dry blending or direct compression in a dry room avoids most problems. See ingredients for tablets.
• Powders and drink mixes. Pre-disperse the powder with other dry ingredients or add it slowly to a stirred liquid to prevent lumps. Lower-molecular-weight grades give thinner drinks. See ingredients for powders.
• Gummies. Heat, acid and water together can depolymerise the chain. Include molecular weight, not only content, in stability testing. See ingredients for gummies.

Hyaluronic acid is often combined with chondroitin sulfate, hydrolysed collagen and MSM. Several of these materials also take up moisture, so test flow and caking of the full blend. Other materials in this group are listed under joint and connective tissue.

The ingredients list under Regulation (EU) No 1169/2011 should name the substance actually used, salt or acid. The quantity declared should use the same basis as the assay. The guide to labelling a food supplement covers the wider requirements.