Study record
MASTERS trial (metformin + resistance exercise interaction)
Muscle mass / strength gains from resistance training
Human — Older adults, supervised resistance-training program, MASTERS trial Tier 2 · Human clinical/functional RCT verification: verified
1. Species / populationOlder adults, supervised resistance training, MASTERS trial
2. Exposure, route, scheduleMetformin, oral, concurrent with resistance training, per protocol
3. Comparator & durationResistance training + placebo; per MASTERS protocol duration
4. Endpoint & numeric resultMetformin blunted muscle mass/strength gains vs training + placebo
5. What this study did NOT establishNo lifespan data; finding specific to the resistance-training + metformin combination
Full record
| Intervention(s) | Metformin, Resistance Exercise |
| Species | Human |
| Population | Older adults, supervised resistance-training program, MASTERS trial |
| Sample size | not specified in source participants verification: verified_2026-07-11 |
| Exposure | metformin, oral, concurrent with structured resistance training — Per MASTERS trial protocol verification: verified_2026-07-11 |
| Comparator | Resistance training + placebo |
| Duration | Per MASTERS trial protocol (duration not detailed in sourcing brief) |
| Endpoint | Muscle mass / strength gains from resistance training |
| Evidence tier | Tier 2 · Human clinical/functional RCT |
| What was NOT established | Did not test lifespan. Establishes a negative training-drug interaction (metformin blunts exercise adaptation in older adults); does not generalize to metformin's effects outside the resistance-training context or in non-exercising populations. |
Result values (as reported in sourcing brief)
| interpretation | Metformin BLUNTED resistance-training-induced muscle mass/strength gains relative to training + placebo -- a negative training-drug interaction |
| verification | verification: verified_2026-07-11 |
Source citation
Verification status: verified This record was checked against its primary publication on 2026-07-11.Identifiers: PMID verified; DOI verified; PMC verified; trial registry ID not reported. Record-level verification and identifier-level status are separate: a record can be fully verified against its primary publication while an identifier that does not apply to the study type — a trial registry ID for an animal study, for instance — is marked not applicable. No identifier is fabricated, and none is left in a “pending” state.
| trial name | MASTERS |
| pmid | 31557379 verified |
| doi | 10.1111/acel.13039 verified |
| journal | Aging Cell 2019 |
| trial registry id | not reported not reported |
| pmc | PMC6826125 verified |
| authors | Walton RG, Dungan CM, Long DE, et al. (MASTERS) |
| year | 2019 |
| verified date | 2026-07-11 |
| verified note | 1700 mg/d metformin (n=46) vs placebo (n=48), 14 wk progressive resistance training; placebo gained MORE lean/thigh muscle mass (p=.003/<.001); metformin blunted mTORC1 trend, raised AMPK — MATCHES. Moteksempel: geroprotektiv intervensjon svekket en aldringsrelatert respons. |
| verification status | verified |
Funding / conflict of interest
not compiled in this proof-of-concept verification: verified_2026-07-11
Version 0.2.0-mvp · literature search date 2026-07-11 · editorial owner Nabus Research