Underwear that slides down or rolls up? This is the real cause

Underwear that slips down, rolls up, or curls over your hip rarely comes down to your body alone, and almost never to size alone. In most cases, the edge is the cause: a separately attached elastic band presses on a narrow line, and that line shifts as soon as you move. A circular-knit brief with laser-cut edges doesn't have that difference in height, and so it stays where you put it. Below, you'll find each complaint, what's going wrong, and what to do about it.

Which complaint goes with which cause?

Four complaints come up again and again, and each one has a different solution. Find the line that fits you.

Why underwear that slides down usually comes down to the edge

Underwear that's stitched together from separate panels has seams and a separately attached elastic band at the waist and leg openings. That band is thicker than the fabric around it. This means two things: a height difference is created that shows through thin clothing, and all the tension needed to keep the garment in place ends up on that one narrow band.

As long as the tension is exactly right, this works fine. If the band is a fraction too tight, it pulls back to the narrowest point of your body and rolls up. If it's too loose, it loses grip and the underwear slides down. There's barely any middle ground, because there's only one line doing the work.

With a seamlessly knitted garment, it's different. The fabric is knitted into shape rather than cut from panels, and the edges are laser cut. There's no attached band and no seam. The tension spreads across a wide area instead of a single line. That's why seamless underwear slides down less and shows through less, and it's a difference in construction, not a matter of better fabric.

The four causes, from most to least common

1. An attached elastic band

By far most complaints come from this. Feel the waistband of your underwear with your fingers: if you feel a clear thickening, you have an attached band. That's exactly where it rolls up and where it shows through.

2. A size chosen too small

A smaller size feels tighter and therefore safer in the fitting room, but does the opposite in practice. Too little fabric pulls back to the narrowest point. At the waist, that's the spot just below your navel, at the leg it's the top of your thigh. That's exactly where the rolling up begins.

3. The wrong style for your proportions

A thong that creeps into your seat is usually not a sizing issue but a style issue: the back panel is too narrow for the width of your hips. More fabric at the back solves this, and shorts do so most completely.

4. Elastic that has worn out

Elastane loses its stretch from heat. A wash at 60 degrees or a spin in the dryer does more damage than a year of wear. If underwear that used to fit well suddenly starts sliding down, that's almost always the laundry, not your body.

You can read more about edges that show through in our article on underwear under white clothing, where the same construction makes the difference.

Why going down a size makes the problem worse

The instinct when underwear slides down is to order a size smaller. That backfires, for the same reason shapewear rolls down. A garment that's too small doesn't have enough fabric to cover the volume, so it pushes that volume toward the edges. The edge then has to handle even more tension and pulls back even further.

If you fall between two sizes, take the larger one. It gives a smoother line than the smaller size, which curls up, and you determine your size based on your hip measurement, not your clothing size. The same principle applies to shaping underwear, which you can read about in our article on breathable shapewear.

Thong, brief, or short: what stays in place best?

The more continuous fabric a piece of underwear has, the less chance something shifts. That's an argument for shorts, though not every outfit calls for them.

Thong. The LumaPure Thong (€37,95) has a high waist and a seamless finish, and is available in sizes XS/S through 5XL in three colors. If a thong always rides up on you, this isn't the style for your proportions.

Brief. The LumaPure Brief (€37,95) gives a smooth line over the hip with a soft high waist, in the same size range from XS/S through 5XL. This is the style that stays in place best for most women during an ordinary day.

Short. The LumaPure Short (€37,95) extends to mid-thigh, with subtle shaping and light waist support. Available from XS/S through 3XL/4XL in five colors. Because the panel is longer, there's simply less edge that can roll down, and it solves chafing thighs as well.

High waist with light support. The Luma Contour Slip (€29.95) combines a seamless high waist with light support around the tummy and comes in twelve colours, size S to XXL. For wearing under a fitted outfit, this is the style that keeps your midsection smooth without leaving a line.

How to keep new underwear in place

The elastane does the work, so treat it accordingly. Wash at 30 degrees in a wash bag or by hand, skip the fabric softener and let it air dry. The tumble dryer is the fastest way to make a well-fitting pair sag, because heat permanently damages elasticity.

Rotating your underwear also helps. Elastane needs time to spring back; a pair worn on two consecutive days doesn't fully recover its tension. A larger stock therefore makes each piece last longer than a small one.

Want to see more styles side by side? Browse the briefs, thongs and shorts collection or the broader underwear collection.

Frequently asked questions about underwear that slides down

Why does my underwear slide down even though the size is right?

It's almost always the waistband. A narrow applied band puts all the tension along one line, and as soon as that line is slightly too loose or too tight, the pair shifts. A circular-knit style with laser-cut edges spreads that tension over a wide area.

Does a smaller size help with underwear that rolls up?

No, that usually makes it worse. Too little fabric pulls back to the narrowest point of your body, and that's where the rolling starts. If in doubt, go for the larger of two sizes and base it on your hip measurement.

Why does my thong creep into my seat?

Because the back panel is too narrow for the width of your seat. That's a style issue, not a size issue. A brief or a short gives more continuous fabric at the back and solves it.

Why does the leg opening of my shorts roll up?

Because of a finished leg band that pulls back on your thigh, or because the shorts are a size too small. A laser-cut leg edge without an applied elastic doesn't have that pulling force.

Does seamless underwear really not show lines?

A true circular-knit style with laser-cut edges has no band and no seam, so there's no height difference pressing through your clothing. Just make sure the size is right: underwear that's too small creates a line of its own by pushing volume out to the side.

How do I wash seamless underwear without it stretching out?

At 30 degrees in a wash bag or by hand, without fabric softener, and left to air dry. Not in the dryer: heat damages the elastane, and it's exactly that elastane that keeps the briefs in place.

How long does underwear keep its shape?

This mainly depends on how you wash it and how often you wear the same piece. Elastane needs a day to spring back, so alternating between pieces noticeably extends their lifespan. If the waistband stays loose after stretching, the elastic is worn out.

Can I try it at home first?

Yes. Every order comes with try first, pay later, with a 14-day reflection period. Shipping costs €3.95 and is free from €50. Whether briefs stay in place is something you only notice after a normal day, not in a fitting room.

Not sure which size you need? Start with the size guide. Two measurements, two minutes, and then you choose based on your own circumference instead of your clothing size.

Written by Team Novyre, specialists in seamless underwear. Last updated: 21 August 2026.