Can stretching alone build muscle?

Short answer

No, not with normal stretching. In a 42-study analysis, a small effect showed up only with 15 minutes or more per session, 5 or more times a week, for 6 weeks or more, and a panel of 20 experts agreed stretching does not meaningfully build muscle.

Can stretching alone build muscle?
'Stretch → muscle stimulus → more muscle' — does this formula hold?
Some say that holding a muscle in a long stretch is enough to make it grow. In animal studies, stretching for hours a day made muscles grow a lot. We checked whether people can build muscle from stretching alone, without lifting.
One hour a day for 6 weeks
The calf muscle got 15.2% thicker
Of 52 people, 27 wore a brace that stretched one calf for 1 hour a day for 6 weeks. The stretched calf muscle grew 15.2% in cross-section, and maximal strength went up too. Stretching alone made the muscle grow.
Chest: 15 minutes a day for 8 weeks
About 6% thicker, similar to lifting
Of 81 people, one group stretched the chest on a device 15 minutes a day, 4 days a week; another lifted 3 days a week, 5 sets of 12, for 8 weeks. Chest thickness rose 5.65-6.46% with stretching and 5.35-7.25% with lifting, with no difference between groups.
But pool the studies
The effect was small
A 2024 analysis that pooled 42 studies with 1,318 people rated stretching's effect on muscle size as small. Another 2024 analysis of 25 studies rated it as close to nothing, and people who did not exercise beforehand showed no effect.
It depends on the dose
Pooled, under 15 minutes or under 5 times a week made no difference
In the 42-study analysis, muscle grew only with 15 minutes or more per session, 5 or more times a week, for 6 weeks or more. Shorter or less frequent stretching showed no meaningful difference from not stretching. Most of the biggest effects came from a single research group. The chest study above (4 times a week) is an exception to this average.
What 20 experts concluded
Stretching does not meaningfully build muscle
In 2025, 20 stretching researchers issued recommendations that needed at least 80% agreement. They agreed stretching widens how far joints can move and reduces muscle stiffness, and also agreed it does not meaningfully add to muscle growth.
Bottom line: normal stretching does not build muscle
Lift for muscle, stretch for flexibility
Very long stretching, like 1 hour a day, grew muscle a little, but a few minutes before or after a workout made no meaningful difference. Build muscle with strength training, and use stretching to become more flexible.