Underwear That Does Not Ride Up – The Secret Is the Fit

Short answer: Underwear that does not ride up is above all a question of the right size, enough leg length and a good leg opening. Get those three right and the leg stays in place all day, including in bamboo. The material alone does not solve the problem.

Why the leg rides up

The thigh is wider than the knee, so gravity and movement work against any opening sitting on the thigh. Every time you take a step, the thigh pushes the fabric slightly upwards, and with nothing holding it back, the opening ends up where the leg is narrowest. That is geometry rather than a fault in the item.

Size is the most common cause

If the item is too small, the fabric is stretched thin over the thigh, and stretched fabric slides more easily than relaxed fabric. If it is too big, it folds and is pushed up by the folds themselves. Measure your waist and use the brand's own chart rather than the trouser size you usually take, as the two rarely line up.

The leg length has to suit your thigh

The opening has to end past the widest point of the thigh, not on it. If it ends in the middle of the widest part, it has nothing to hold on to and rides up at the first step. A longer model therefore often solves a problem that a tighter fit never could. See bamboo underwear for men.

The opening is what holds

A soft silicone strip on the inside of the leg opening grips the skin without pinching, and that is the solution that works best. A wide, softly knitted opening is second best. A narrow elastic that pinches is the worst, because it both leaves marks and still slides once the skin turns damp.

Moisture makes everything worse

Damp skin is slippery, and damp fabric slides more easily. That is why the leg rides up most late in the day, in heat and during activity. Bamboo viscose moves the moisture away from the skin and out into the fabric where it evaporates, so the leg stays put longer than in a cotton item with the same cut.

How to test a model

Put the item on and walk for half an hour, preferably up some stairs. If the opening has moved more than a couple of centimetres, it does not work for you. At the same time check whether a red mark is left behind, because an opening that holds by pinching is not a solution but a different problem.

When nothing works

If you have tried the right size, longer legs and a silicone edge without success, the cut of that model is probably not made for your body shape. Change brand rather than trying a fourth size, because leg width and rise vary more between brands than within one brand's sizes. See also size guide, the right fit and washing guide.