Muscle growth mainly happens because the tiny fibers that make your muscles contract get bigger and stronger; the fluid part of the muscle increases too, but only as a side effect and not on its own.

When muscles get bigger from working out, it’s not really because they’re storing more water or sugar—those changes don’t last or help much. What really matters is that the actual muscle fibers grow thicker.

When muscles get bigger over time, it’s not because the non-working parts inside them swell up—it’s because the actual muscle fibers that do the contracting grow more, and that’s what really matters.

When muscles get bigger over time, it’s not because the non-working parts inside them swell up—it’s because the actual muscle fibers that do the work grow more, and that’s what really matters for lasting muscle growth.

When muscles get bigger over time, it’s not because they’re filling up with water or sugar stores—it’s because the actual muscle fibers are adding more contractile proteins.

When muscles get bigger over time, it’s not because they’re just storing more water or sugar—those things don’t stick around. Instead, muscles grow mainly by adding more of the actual contractile parts that make them strong.