Resveratrol is a naturally occurring polyphenol found in the skin of red grapes, certain berries, and the root of Polygonum cuspidatum (Japanese knotweed). Over the past two decades it has become one of the most studied botanical actives in the dietary-supplement and functional-food industries, driven by interest in its antioxidant and cellular-health properties.
Where resveratrol comes from
Commercial resveratrol is most commonly sourced from Polygonum cuspidatum extract, which delivers trans-resveratrol at standardized purities. When evaluating a supplier, the two numbers that matter most are the trans-resveratrol assay (typically 98% or 50% for the branded extract grade) and the trans:/cis ratio, since trans-resveratrol is the form most referenced in the literature.
Stability is the real challenge
Resveratrol is sensitive to light, heat, and oxidation. Left unprotected, potency can degrade during storage and inside finished capsules. Buyers should ask for:
- HPLC or UV assay on both incoming and aged samples
- A validated stability study under accelerated conditions
- Packaging guidance (low-oxygen, light-protected) from the supplier
Formulation considerations
Because of its low aqueous solubility, resveratrol is frequently delivered in powder blends, softgels, or inclusion complexes. If you are building a finished product, align the raw-material specification with your target dose and format early — it is far cheaper to specify correctly at the purchase-order stage than to rework a formula later.
What to put on the purchase order
A clear specification protects both sides. At minimum, state the required trans-resveratrol percentage, acceptable heavy-metal limits, microbial limits, country of origin, and the test method (HPLC preferred). Requesting a current Certificate of Analysis with every lot is non-negotiable for a branded ingredient.
Need a resveratrol specification sheet or sample? Talk to our technical team about grades, documentation, and private-label options.
