Plant-compound muscle supplements: what five trials in older adults found

If you have seen ads for plant-based muscle supplements, here is what the research says so far: the results are mixed, and nothing is settled. That leaves your routine of lifting and eating well right where it was, as your best bet.

In a review of five randomized trials in adults aged 55 and older, supplements made from plant compounds called polyphenols raised strength in two trials, gave inconsistent results for muscle size, and improved balance or everyday function in two of the three trials that measured it. The researchers say the evidence is still too small to support recommendations.

How the study worked

Researchers searched for every randomized controlled trial (the kind where people are randomly assigned to a supplement or a comparison group) testing polyphenols in adults aged 55 and older. They found six trials. Five had results and went into the review, and the sixth is still underway. The review was published on November 4, 2026 in Geroscience. The trials were too few and too different from each other to combine into one number, so the authors described the pattern across them instead.

What are polyphenols?

Polyphenols are natural compounds found in plants. The supplements in these trials included quercetin, extracts rich in epicatechin, tea catechins, cocoa flavonoids and polyphenols from marine sources. Lab work suggests these compounds might calm some of the processes that wear down muscle with age, such as inflammation and cell stress. The question here was whether that shows up in real people.

What they found

The trials lasted from 4 to 24 weeks. Here is how the results lined up:

• Strength: Muscle strength was significantly better in the supplement group than in the comparison group in two of the five completed trials.
• Muscle size: Results were inconsistent. One trial showed a significant difference, but there the people were taking polyphenols, amino acids and exercise together, so it is hard to credit the polyphenols alone. In another, people lost less muscle, but the gap between groups was not big enough to count as significant. The rest showed no effect or an effect that was hard to pin on the supplement.
• Balance and daily function: These improved in two of the three trials that measured them.

So the picture is this: some signals, no consistent pattern. The authors call the effects biologically plausible but currently inconsistent. In plain words, the idea makes sense, but the proof is not there yet.

What happens next?

The authors say larger, standardized trials are needed. They want these done in people with confirmed sarcopenia, which is age-related muscle loss, and with direct tests of how nerves and muscles work together. Until those results arrive, these supplements are an open question rather than a proven fix.

That is useful to know. You do not need to chase a new powder or capsule to protect your muscles. The one trial with a clear muscle-size result paired the supplement with exercise, which points back to the habits you already control.

What you can do today

While your coffee brews, stand up from a sturdy kitchen chair and sit back down slowly a few times. It takes a minute, needs no equipment, and counts as strength work. Then keep up the lifting and the good meals you already have going.

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