I Tried Thrivin's Sculpting Flare Leggings … and My Butt Has Never Looked Better

There is a very specific disappointment that comes with taking sculpting leggings out of the packaging. You know the one. The photos showed a lifted, round, gravity-defying shape. What arrives is a tube of thin black fabric that flattens everything it touches and goes semi-transparent the moment you bend.

I have been through that cycle enough times to become genuinely cynical about the category. So when three separate people in my Saturday class turned up in the same flared black leggings within a fortnight, my first reaction was not where are those from. It was here we go again.

Then I got a proper look at the back of them mid-squat, and I stopped being clever about it and asked.

They were Thrivin's Elevate™ Sculpting Mid V-Waist Flare Leggings. I ordered a pair in Night Black, mostly so I could write about why they did not work. Three weeks later I have worn them roughly every other day and bought a second pair in Coffee. This is the honest version of what happened in between.

The first thirty seconds tell you almost everything

Pick them up and the weight is the first surprise. These are not the papery, four-for-thirty leggings that live at the front of a sports shop. The knit is dense and slightly springy, with a faint ribbed texture you can feel more than see. Stretch a section between your hands and it does not go pale or sheer. It resists you, then snaps back flat with no memory of where you pulled it.

That density is the whole trick, and it is where most sculpting leggings quietly cheat. Thin fabric cannot hold anything. It can only sit on top of you.

The second thing you notice is the waistband, and it is not shaped like a normal one.

The V-front waistband is doing more work than it looks like

Most high-waisted leggings run a straight, flat band across the front of your stomach. It is the simplest thing to manufacture and the least flattering thing to wear, because a horizontal line cuts your torso in half at its widest point and every soft bit above it has to go somewhere.

Thrivin's band dips into a V at the centre front instead. It sits mid-rise, just under the navel, and the two sides angle up towards your hip bones. The effect is almost embarrassingly simple: your eye follows the V downwards, your torso reads longer, and the narrowest visible point of your waist moves up to where you actually want it.

Practically, three things follow from that shape. It does not roll down when you hinge forward, because there is no single straight edge for your stomach to fold over. It does not create a muffin line, because the band is wide and the compression is graduated rather than a hard elastic ring. And because it sits mid-rise rather than up under your ribs, you can actually breathe out after lunch.

I have owned high-waisted leggings that were structurally a corset. These are not that. They hold, they do not squeeze.

The mirror moment

I want to be precise here, because "they lift your butt" is the kind of claim every brand makes and almost none of them earn.

What these actually do is change the shape of the silhouette from behind in three separate ways at once. The knit is denser and more compressive through the thigh and the outer hip, so that area is pulled in and smoothed. A centre seam runs up between the glutes and curves outward, which gathers the fabric slightly and follows the natural round of the muscle instead of flattening across it. And the panel over the glutes is knitted with more give than the compression around it, so the fabric sits up on the fullest part rather than dragging it down.

Put together, the result is a rounder, higher, more separated shape. It is not an illusion that disappears when you move, either, which was my main suspicion. Because the shaping is knitted into the structure rather than printed or padded, it holds through a walk, a lunge and a full day of sitting at a desk.

My honest reaction, alone in a bedroom with a phone camera, was a slightly undignified noise. I sent the photo to two friends. Both of them bought a pair within the week.

Why the flare is not just a trend

I assumed the flared hem was a styling decision borrowed from the early 2000s. It is partly that. But it also does something structural to your proportions that a straight ankle cannot.

A tapered legging ends narrow at the ankle, which visually pulls the whole leg inwards and makes your hips read as the widest point of the outfit. A flare does the opposite. It widens gradually from the knee, so your hip and thigh become the narrow part of the shape relative to the hem. Your legs read longer, your waist reads smaller, and the whole silhouette balances out.

The practical bonus nobody mentions: a flare hides a lot. Trainer, sock line, ankle, all of it disappears under the hem, so you can leave the gym and walk into a coffee shop without looking like you have come straight from the gym.

The squat test, and the thing I actually cared about

Every pair of black leggings looks opaque standing still in your bedroom. The only test that counts is the one under gym lighting at the bottom of a squat, with a mirror behind you.

I did it properly: bodyweight squats, hip thrusts, a set of deep sumo squats where the fabric is stretched about as far as it will ever go, all under the flat overhead lights that expose everything. They stayed completely opaque. No lightening at the seat, no grey patch across the stretch, no shadow of a seam.

Two smaller things earned them a lot of goodwill. They do not slide down during a set, so I was not hitching them up between reps. And the seam that runs up the centre back stays where it is put. It does not migrate or bunch, which is the single most annoying failure mode of scrunch-style leggings.

Sizing: the one thing I would tell you before you order

Thrivin lists these as true to size, and says to size up if you are between sizes. Based on my pair and a long read through what other buyers have written, that advice is right but slightly understated.

These are a high-compression legging. That means the size that fits you in a soft everyday legging will feel considerably tighter here, which is the entire point, because the shaping comes from the fabric holding you. If you like a firm, held-in feel, take your normal size. If you are between sizes, prefer a little breathing room, or you are fuller through the glutes and thighs relative to your waist, go up one. The waistband has enough give that a slightly loose band is far more comfortable than a slightly tight leg.

Sizing up is easily the most repeated piece of advice in the customer reviews, usually written by people who love the leggings anyway.

Length is the other variable, and it is the reason Thrivin sells the flare in Short, Regular and Long. A flare is supposed to break over the top of your shoe. Too short and it reads like a cropped bootcut; too long and it drags on the floor and frays at the hem.

Gym clothes you can actually leave the gym in

This is where the flare quietly justifies itself. A tapered gym legging with a visible logo down the thigh announces exactly what you have been doing. These read as trousers. Paired with a jacket or an oversized shirt, nobody looks twice.

I have now worn mine to a 7am class and then straight through the supermarket, a coffee, a school pick-up and dinner, and changed nothing but the top. That is not a small thing when your morning has a two-hour window in it.

What I would change

I am not going to pretend these are perfect, because a review with no criticism is an advert.

The compression is firm, and that is a preference. If your idea of comfortable is a buttery, barely-there legging you forget you are wearing, this is not that. You feel these. I like it, for the same reason a good sports bra feels supportive rather than invisible, but if you hate anything tight through the thigh, go up a size or look at a softer knit.

The Regular length is generous. At 5′5″ I am at the shorter end of what Regular is drafted for and mine just clear the floor in flat trainers. If you’re around 5′3″ or shorter, check the Short length. This is a flare, so hemming it yourself changes the shape of the leg and is not really an option.

They need air drying. Machine wash cold, inside out, and then hang them. A tumble dryer is what kills the elastane in any compression fabric, and the shaping is the entire reason you bought these. It takes a night on a rack. Adjust your laundry habits, not the leggings.

You will want a second pair. Not a real criticism, but a real financial hazard. There are twelve colours, and the muted ones (Coffee, Latte, Winter Plum) are genuinely lovely in person.

Midnight Navy

Coffee

Latte

Merlot

Winter Plum

Candy Pink

Six of the twelve. Also in Night Black, Dark Mauve, Cotton Pink, Harbor Blue, Mint Julep and Fine Wine.

I am not the only one

Before I bought mine I read a few hundred customer reviews, which is a habit I recommend. Two themes come up over and over: the shape they create, and the advice to size up. These are unedited.

So, do they look like the pictures?

Yes, and I resent it slightly.

I ordered these expecting to write a piece about how sculpting leggings are marketing. Instead I have a pair I reach for first, a second pair in Coffee, and two friends who now own them because of a photo I sent at eleven at night.

The reason they work is not complicated and it is not magic. It is a dense, high-compression knit instead of a thin one; shaping built into the structure of the fabric rather than printed on top of it; a waistband cut in a V instead of a straight line; and a hem that flares to rebalance the whole silhouette. Every one of those is a manufacturing decision that costs more than doing it the cheap way, and you can feel all four of them the moment you put the leggings on.

If you have been disappointed by every pair that promised a lift, these are the ones that will make you stop looking.

Quick answers to the things people asked me