Resveratrol, exercise and grapes
In this investigation
The question behind a grape purchase
I was considering grapes as another fruit. The trials below tested isolated preparations, not grape portions.
A smaller aerobic gain in older men
In 27 inactive men aged 60–72, eight weeks of supervised cycling intervals, circuit training and walking were paired with 250 mg trans-resveratrol daily or placebo. Both groups improved maximal oxygen uptake, but the increase was smaller with resveratrol: 308 versus 443 mL/min, with a between-group comparison of P=.03. Several everyday function tests improved in both groups. This was a small trial with numerous outcomes and nominal statistical testing; it does not prove that every resveratrol product impairs every form of training. Danish public research funding supported it; Fluxome supplied tablets and the authors declared no competing interests. Gliemann et al., 2013
Young adults did not get a clear performance advantage
A randomized study in 16 recreationally active young men combined 150 mg trans-resveratrol daily with four weeks of cycling: eight 20-second efforts with ten-second rests, three times weekly. All completed twelve sessions. Peak aerobic power showed a group-by-training interaction, with improvement in placebo only. Oxygen uptake and Wingate peak power improved with training, but their interactions did not establish different responses. This is closer to my interval format, although cycling and running differ. The trial used corrections for post-hoc comparisons, not an identified correction across all outcomes. Its small sample does not establish universal impairment. Scribbans et al., 2014
A positive strength experiment needs its null results too
Another trial paired twelve weeks of aerobic and resistance training with 500 mg daily or cornstarch placebo in adults aged 65–80. Thirty completed; five earlier withdrawals were replaced. Knee-extension average power and average peak torque over seven repetitions showed favorable group-by-training interactions (P=.004 and .038). Other muscle-function indices did not differ with treatment, lean body mass did not significantly change, and the oxygen-uptake interaction was inconclusive (P=.09). These are selected positive functional findings. Multiple tests and a completer analysis limit confidence. NIH funding was reported; the authors declared no conflicts. Alway et al., 2017
A larger pilot still did not settle efficacy
Sixty adults aged at least 65 with functional limitations were randomized to placebo, 500 mg or 1,000 mg daily, with twelve weeks of twice-weekly walking and resistance training. Five did not complete; the paper modeled all randomized participants. Its 33.1 m six-minute-walk improvement at 1,000 mg, versus 9.45 m with placebo, describes separate within-group changes. It is not a reported statistically established between-arm advantage. The dated 2015 protocol and current registry identify usual gait speed as primary; this was explicitly an underpowered feasibility pilot. Gastrointestinal complaints occurred. NIH and other research support funded it, and one author consulted for the tablet supplier. Harper et al., 2020/2021, protocol, registry
The 2026 lifting evidence is preliminary
Two conference abstracts tested a 500 mg daily dispersible formulation, seventeen-day periods and flywheel squats in young trained men. Their matching authors and protocols suggest overlapping participants; they are not established independent replications. The 19-person recovery report found higher isometric force and force-development rate overall, but no treatment-by-time recovery interactions or better jump recovery. The 13-person power report found no consistent benefit; one comparison favored placebo. Full participant flow, endpoint hierarchy, funding and safety reporting were unavailable in these abstracts. They are preliminary findings rather than a confirmed performance product. SEACSM 2026 original abstracts P307 and P403, printed pages 157 and 171
What I would change
I can choose grapes for enjoyment. These results do not establish a resveratrol supplement benefit for my training or justify restricting fruit. Study doses are not a regimen.
The antioxidant investigation develops the food-versus-supplement distinction; the longevity frontier covers the separate NR-plus-resveratrol disease trial.