Resveratrol vs Quercetin: What to Choose and for Whom

Resveratrol and quercetin are sold under similar promises — "antioxidant protection", "vascular health", "longevity". But a person who trains, has specific goals or takes medications continuously needs not a promise but an answer: whether there is any point in the supplement at all and which one to prefer. The editorial team has examined typical scenarios of choice.

An honest starting point

Before comparing, it is worth acknowledging: neither resveratrol nor quercetin is an essential substance, and for neither has it been proven that taking it in supplement form prolongs life or prevents disease in humans. Both have convincing results in cells and animals, but far more modest ones in clinical studies.

The choice between them is therefore not a choice of "medicines" but a decision on whether it is worth spending money on a supplement with a limited evidence base, and if so, for what specific goal. For many people the right answer will be "neither", and the editorial team considers this answer just as legitimate as any other.

The second starting point is diet. Quercetin can be obtained from onions, apples, berries and tea, and people with a varied plant-based diet already get tens of milligrams per day. Very little resveratrol comes from food, and the dose used in research is achievable only from supplements.

The third is your context: whether you train for adaptations, whether you take medications, whether you have chronic diseases. These factors often matter more than a comparison of the molecules themselves.

Scenarios: who each may suit

People interested in general "metabolic support" against a background of excess weight or insulin resistance are often offered resveratrol. Individual studies described improved insulin sensitivity, but the results are heterogeneous, and the review by Smoliga and colleagues (2011) emphasizes the lack of large long-term studies. The foundation here remains nutrition, movement and, if needed, treatment from a doctor.

People with seasonal allergic manifestations, or those interested in an anti-inflammatory action, are more often offered quercetin — because of laboratory data on mast cell stabilization. However, clinical evidence for treating allergy is insufficient, and quercetin does not replace antihistamines or the prescriptions of an allergist.

For endurance amateurs seeking a small edge, quercetin looks the more justified option. The meta-analysis by Kressler and colleagues (2011) showed a statistically significant but small effect on endurance — an effect whose practical significance for trained people is limited.

People who simply want "more antioxidants" are advised by the editorial team to start with the plate: several servings of vegetables and fruit of different colors every day provide a broad spectrum of polyphenols, including quercetin, without the risk of excessive doses and interactions.

For athletes: when polyphenols can get in the way

Physical exercise creates oxidative stress in the muscles, and it is precisely this that is one of the signals triggering adaptations: the formation of mitochondria, the strengthening of the body's own antioxidant enzymes, improved insulin sensitivity. Massively "quenching" this signal with supplements can partly suppress the training effect, as Merry and Ristow (2016) write.

The most telling for resveratrol is the study by Gliemann and colleagues (2013): in older men who trained for eight weeks, taking resveratrol weakened the improvement in cardiovascular measures, in particular maximal oxygen uptake, compared with placebo. This is a direct argument against taking resveratrol during a period when the goal is progress.

For quercetin there is no such direct negative signal in humans, but the logic of caution is the same. If one is going to take polyphenols, it is more appropriate to do so at moderate doses rather than in "megadoses", and not during a period when the main goal is maximal adaptations.

A different situation is the competitive period, when the priority is not adaptation but recovery between starts. Here the debate about the benefit of polyphenol products, such as cherry juice, continues, but this is a different question from daily intake of resveratrol "just in case".

Form, dose and quality

For resveratrol, on the label it is worth looking for trans-resveratrol with a stated purity. Products based on Japanese knotweed extract may also contain emodin, which has a laxative effect; quality manufacturers indicate its content or absence. Studies used a very wide range of doses — from tens of milligrams to several grams per day, with higher doses more often causing gastrointestinal disturbances.

Quercetin is most often sold as the aglycone (quercetin dihydrate), as well as in the form of phytosomes with phospholipids or enzymatically modified isoquercitrin. The latter two forms give higher plasma concentrations in pharmacokinetic studies. Typical doses in studies are hundreds of milligrams per day, in particular around 1000 mg in endurance work.

• choose products with a standardized content of the active substance and a certificate of analysis;
• do not combine several "antioxidant" complexes at once, so as not to end up with a total megadose;
• take with food containing fats — this can improve absorption and tolerance;
• for athletes who undergo doping control, certification of the supplement for the absence of banned substances is important.

Another piece of quality advice: polyphenols are sensitive to light and oxidation, so supplements should be stored in tightly closed, opaque packaging, away from heat and moisture.

Finally, it is worth setting up a time-limited "experiment" with clear criteria: what exactly you expect to change and how you will measure it. If there are no changes after a few weeks, it is more sensible to stop taking it than to raise the dose.

Interactions and who should avoid them

Quercetin inhibits the enzyme CYP3A4 and the transporter P-glycoprotein, which are responsible for the metabolism and elimination of many drugs. Theoretically this can raise the concentration of some medications — from statins to immunosuppressants. People who take medications continuously should discuss quercetin with a doctor or pharmacist.

Resveratrol in laboratory studies inhibits platelet aggregation and affects cytochrome P450 enzymes. Caution is therefore needed with anticoagulants and antiplatelet agents, as well as before planned surgery. A doctor's recommendation is mandatory here.

For pregnant and breastfeeding women, taking supplements with high doses of polyphenols is not recommended due to a lack of safety data. People with kidney diseases should avoid high doses of quercetin, and people with hormone-dependent conditions should discuss resveratrol with a doctor because of its weak estrogen-like activity in laboratory models.

During treatment of oncological diseases, any antioxidant supplements, including both substances, should be coordinated with an oncologist, since they can theoretically interact with chemotherapy and radiation therapy.

Editorial conclusions

For most people neither supplement is obligatory: quercetin comes from a varied plant-based diet, and convincing clinical evidence of resveratrol's benefit in humans is lacking.

If choosing between them for athletic purposes, quercetin has a small but more consistent signal for endurance, whereas resveratrol during a training period may even weaken adaptations.

The key caveats are interactions with drugs for both substances and the principle of "moderate doses" instead of megadoses. Any intake should be treated as a time-limited experiment with clear criteria.

For a deeper understanding of the topic we recommend the editorial pieces "Resveratrol or Quercetin: What's the Difference", "Antioxidants and Training Adaptations" and a review of the evidence on cherry juice for recovery.

References

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2. Gliemann L, Schmidt JF, Olesen J, et al. Resveratrol blunts the positive effects of exercise training on cardiovascular health in aged men. J Physiol. 2013;591(20):5047–5059.
3. Kressler J, Millard-Stafford M, Warren GL. Quercetin and endurance exercise capacity: a systematic review and meta-analysis. Med Sci Sports Exerc. 2011;43(12):2396–2404.
4. Merry TL, Ristow M. Do antioxidant supplements interfere with skeletal muscle adaptation to exercise training? J Physiol. 2016;594(18):5135–5147.
5. Walle T, Hsieh F, DeLegge MH, et al. High absorption but very low bioavailability of oral resveratrol in humans. Drug Metab Dispos. 2004;32(12):1377–1382.
6. Li Y, Yao J, Han C, et al. Quercetin, inflammation and immunity. Nutrients. 2016;8(3):167.
7. Maughan RJ, Burke LM, Dvorak J, et al. IOC consensus statement: dietary supplements and the high-performance athlete. Br J Sports Med. 2018;52(7):439–455.