# Metformin Added Nothing to Diet and Exercise for Older Adults' Strength

*Metformin added to lifestyle intervention for physical function in older adults with obesity (DEMFOS trial): a randomised controlled trial.*

- **Evidence Level**: Strong
- **Publication Types**: Journal Article
- **Journal**: The lancet. Healthy longevity
- **Sample Size**: 114 adults aged 65-85 with obesity, mostly men
- **Authors**: Nava MLD, Viola V, Aguilar M, Bryant MS, Nambi V, Armamento-Villareal R, Qualls C, Villareal DT
- **Published**: 2026-07-31
- **Topics**: metformin, exercise, healthy aging
- **DOI**: https://doi.org/10.1016/j.lanhl.2026.100883
- **Original Source**: https://pubmed.ncbi.nlm.nih.gov/42532077/

## Summary

Metformin has a big fan club in longevity circles, but this trial puts a dent in the hype. Older adults with obesity, aged 65 to 85, did six months of serious diet and exercise coaching. Adding metformin on top gave zero extra improvement in physical function compared to a placebo. The lifestyle program itself was what moved the needle.

## Practical Takeaway

This study suggests structured exercise and diet drive physical function gains, not metformin.

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