Women build muscle at the same relative rate as men
On identical programmes, men gained slightly more muscle in absolute terms, mainly in the upper body. Relative to starting size, gains were the same.
What they studied
- Design
- Systematic review with Bayesian meta-analysis
- Data
- 29 studies (2,720 screened)
- People
- Healthy men and women aged 18–45 on the same resistance programme
- Outcome
- Absolute and relative change in muscle size
What they found
- Absolute gains slightly favoured men (standardised difference 0.19).
- Relative gains, as a percentage of starting size, were essentially the same (difference 0.7%, uncertainty spanning zero).
- Men gained more absolute size in the upper body, not in the lower body.
- Type II fibre growth was similar between sexes; type I fibre growth slightly favoured men. Training experience did not change the results.
How strong is the evidence
Meta-analysis · 29 studies
What this design cannot tell us:
- Adults aged 18–45 only, and few highly trained participants.
- Most studies were short, so long-term differences are less certain.
What it means for your training
- Same principles, same programme. No special “female” hypertrophy plan needed.
- Judge progress against your own starting point, not against someone else’s absolute numbers.
Our summary of the published abstract. Read the original paper for full details.