Why leggings go see-through when you bend
Key takeaways
- Stretch thins fabric. Maximum stretch is where opacity fails first.
- A size that has to stretch to fit is already closer to that point.
- Solid black hides thinning better than light or heathered colours.
- The same style can be opaque in one size and not in another.
What happens in the fabric
A knit is a grid of loops. Pulling on it opens the spaces between the loops and reduces the thickness of the fabric across the stretched area. Light that could not pass through the relaxed fabric passes through the stretched one. Bending over stretches the seat more than any other movement you make in a day.
Why size decides it as much as fabric
If the pair has to stretch a long way to fit you, it starts each day nearer to the point where the loops open. That is why a style can be opaque on one person and not on another, and why the review that says it is fine may have been written by someone two sizes down.
What to look at before buying
Fabric weight where the brand publishes it, whether the seat has a heavier panel or a second layer, and the colour. Solid dark colours hide thinning; light, heathered and marled colours show it soonest. A brand claim on its own is not checkable.
How to test a pair you own
Put them on in daylight, bend forward, and have someone look, or squat in front of a mirror with a light behind you. Do it in the size you actually wear. That is the only test that answers the question for your body.
Related questions
- leggings see through when bending
- how to tell if leggings are see through before buying
- opaque leggings what to look for
Related guides
Frequently asked questions
- Why are my leggings see-through when I bend over?
- Bending stretches the fabric across the seat to its maximum, which opens the knit and thins it. A size that already has to stretch to fit, a low fabric weight or a light colour each bring that point closer.
- Does black always stay opaque?
- No, but solid black hides thinning better than light or heathered colours, so it is the most forgiving choice at any given fabric weight.
- Can I tell before buying?
- Partly. Fabric weight, a doubled or panelled seat and a solid dark colour all help. The definitive test is bending over in the size you actually wear.
Sources
- Knitted fabric - Wikipedia
Background reference for the definitions used in this guide.
Accessed September 1, 2026
- JEGINS Fit problem diagnosis standard
Our published editorial standard for the figures used in this guide.
JEGINS Fit · Accessed September 1, 2026
Scope and limits of this guide
This guide describes what we have measured or sourced. It does not cover every brand, and body measurements vary: use it as a starting point and check the specific product page for its evidence level before buying.