Resveratrol

Which resveratrol to buy?

Resveratrol is available in three forms: natural extract, microbial, and synthetic. The active trans-resveratrol in these three forms is identical, but the ratios between the active trans- and inactive cis-forms differs a lot.

Natural

The natural extracts come from the root of the Japanese knotweed (Polygonum cuspidatum) and from the bark of the Indian kino tree (Pterocarpus marsupium).

Microbial and Synthetic

Microbial and synthetic resveratrol contain only trans-resveratrol and have the advantage of being purer, more sustainable, and of consistent quality.

Cheap

Cheap resveratrol (standard resveratrol) may contain a lot of inactive cis-resveratrol.

Pterostilbene

Trans-pterostilbene is a methylated, naturally occurring form of resveratrol and has better absorption and metabolic stability in the body.

What does it do?

Resveratrol is the first-discovered Salvestrol. It is a remarkable compound known for its supportive influence on the heart and blood vessels.

Resveratrol is also renowned for its strong antioxidant action.

Scientific research into this valuable substance is ongoing, continually revealing new properties. Unfortunately, current legislation prevents us from providing further details.

What is resveratrol?

Resveratrol belongs to the polyphenols, substances that occur naturally in plants having the function of protecting against external influences. For example, UV radiation, fungi, viruses and other stressors.

There are several resveratrols, of which trans-resveratrol and trans-pterostilbene are currently the best known and (as far as we know) most important.

The addition "trans" here means that at the molecular level the double bonds in the carbon chain are on different sides.

Side Effects

In general, no side effects have been reported while using resveratrol. In extremely high doses, gastrointestinal symptoms may occur.

People taking medications such as some statins, blood thinners or anti-depressants should consult with their doctor before taking high doses of resveratrol (more than 900 mg per day).

It is not yet known if there are any interactions between medications that help lose weight and resveratrol. If you are taking medication to lose weight, we recommend consulting your health care provider before using a resveratrol supplement.

Safety

Natural resveratrol (from plants) can be susceptible to contamination with PAHs (Polycyclic Aromatic Hydrocarbons). Because it is known that contaminated resveratrol is on the market, people question whether it is dangerous.

It is important to know if the supplier uses a clean source of resveratrol and can guarantee that the PAHs values are within the legal standard. We therefore recommend to buy only resveratrol from reputable brands. Smeets & Graas regularly tests imported resveratrol products for purity. Should a particular batch not meet the standard, it will be recalled immediately. This way you as a customer can be sure of the quality and purity.

Experiences

Resveratrol is a substance that has generated a lot of scientific attention lately. Studies have recently been conducted in The Netherlands by the UMCG and by Maastricht UMC. It always takes some time before the results of such research are translated into new authorized health claims. However, the findings so far are promising.

We also receive a lot of positive feedback from users about the benefits of resveratrol.

Foods containing resveratrol

Red grapes are relatively rich in resveratrol, but apples, cocoa, peanuts, nuts, (blue) currants and plums also contain resveratrol.

Others also look at:

• Quercetin
• Pterostilbene
• Vitamin D
• Vitamin C
• Vitamin K2

Written by: Marcella van der Wel
Reviewed by: Liesbeth Thoen

Updated: May 3, 2025