Resveratrol

Grades and forms

Resveratrol for food supplements is bought as trans-resveratrol, the isomer named in EU novel food law. The main choice is between high-purity material and botanical extracts standardised to a stated trans-resveratrol content. That choice sets fill weight, colour and the regulatory check you must make.

Material reaches the market by three routes: chemical synthesis, microbial fermentation and extraction from Polygonum cuspidatum (Japanese knotweed) root. The route matters because the Union list has separate entries for synthetic and microbial trans-resveratrol, each with its own specification, and neither entry covers knotweed extracts. Always confirm which entry, if any, the source on the specification sheet matches; for knotweed extracts, confirm their novel food status separately.

Resveratrol sits in the Polyphenols & Flavonoids category. The specification sheet and certificate of analysis state assay, isomer content, particle size and impurity limits. SoleChem sends both with its quote, so state the source, content and physical form you need in the quote form.

EU regulatory status

Resveratrol is not a vitamin or mineral. It is therefore not listed in Annex I or Annex II of Directive 2002/46/EC, which cover only vitamins and minerals and their permitted forms.

Trans-resveratrol is authorised as a novel food under Regulation (EU) 2015/2283. It appears in the Union list of novel foods in Commission Implementing Regulation (EU) 2017/2470. There are two entries, one for synthetic trans-resveratrol and one for trans-resveratrol from a microbial source. Each sets the specification, the permitted food category (food supplements only), the conditions of use and specific labelling requirements, including the designation and a mandatory statement. Read the current consolidated entry before finalising a formula, as amendments can change sources and conditions.

Material outside the entry’s specification may not be covered by the authorisation. This applies especially to extracts from sources or at purities the entry does not describe. The novel food guide explains how to check a material against the Union list.

Novel food authorisation does not replace national rules. Many member states have their own rules on “other substances” in food supplements, and some require notification before placing a product on the market. Check with the competent authority of each target market.

The label must follow Regulation (EU) No 1169/2011 and any designation or statement the Union list entry requires; see the labelling guide. Resveratrol has no E number and is not used as a food additive. For claims, consult the EU Register of nutrition and health claims and the health claims guide.

Formulation notes

Solubility. Resveratrol is poorly soluble in water. It suits capsules and tablets well. In drink powders it needs a dispersion strategy, and in softgels it is suspended in the oil fill rather than dissolved.

Light. The trans isomer converts to the cis isomer under UV light. Protect blends and finished products from light: opaque or coloured capsule shells, film coatings and light-proof packaging all help. Stability studies should track trans-resveratrol content, not total resveratrol.

Colour. The material ranges from off-white to tan. Shade can differ between sources and batches, which shows in white tablets and clear capsules.

Taste. Resveratrol can taste bitter in direct-to-mouth formats. Run taste trials early for powders, chewables and gummies.

Label-claim arithmetic. For a declared amount of trans-resveratrol, the powder needed per serving is the label claim divided by the trans-resveratrol content on the certificate of analysis, expressed as a decimal. For example, an extract at half the declared content needs twice the powder weight. Add any overage your stability data supports; the overage calculator handles the step. Check the result against the conditions of use in the applicable Union list entry.

Combinations. Resveratrol is often blended with other polyphenols such as quercetin. Both are light-sensitive and poorly water-soluble, so the same packaging and dispersion measures apply to the blend.