The Leakproof Thong That Gave Me My Gym Back

18 juin 2026

NIXI Body The Gracie Leakproof Thong — lifestyle shot showing the thong worn under gym leggings, demonstrating the invisible VPL-free fit and discreet leakproof protection for activewear

I've been going to the gym consistently for about four years. Except for the first two or three days of my period, when I've been going inconsistently, reluctantly, or not at all. Not because of cramps — I've made my peace with training through those — but because of the underwear problem.

The underwear problem is this: I wear gym leggings. Gym leggings are tight and light-coloured more often than I'd like. Standard period underwear — the kind with enough absorbency to be useful — shows through leggings in a way that I find distracting and self-conscious-making. A tampon or cup is fine for the heavier days but at the start and end of my cycle, when the flow is light and unpredictable, I want something I can rely on without the bulk and without the visible outline.

I'd been looking for a leakproof thong for about a year. Most of what I found was either not genuinely leakproof or not genuinely invisible. Then I found the NIXI Body Gracie.

What Made This Different

Under gym leggings — completely invisible. This is the photograph that made me order immediately.

I found the NIXI Body Gracie Leakproof Thong while browsing the Women's Underpants collection. The product description called it "our most discreet knicker yet" and "invisible under gym leggings and activewear." I'd seen similar claims before and been disappointed. What made me look more carefully this time was the four-layer gusset construction — the same system used in the brand's fuller-coverage styles, just in a thong format.

NIXI Body The Gracie Leakproof Thong — front product view showing the thong silhouette, low-cut waistband and the smooth nylon elastane fabric construction — The front view — low-cut, smooth, no visible seams. The nylon and elastane outer fabric is what makes it disappear under leggings.

The absorbency spec — up to 10ml, equivalent to one to two tampons — is exactly right for what I needed. Not a heavy-day solution; I have other products for that. A light-day solution: the start of my cycle when things are unpredictable, the last day or two when I'm not sure if I need anything at all but would rather not find out the hard way mid-squat.

The Design

The side profile — the absorbent gusset is integrated into the thong construction without adding bulk or changing the silhouette.

The body is 75% nylon and 25% elastane — the same composition as high-quality activewear, which is why it behaves so well under leggings. It moves with the fabric rather than against it, which is what prevents the bunching and riding that makes some underwear uncomfortable during exercise. The cotton lining against the skin is soft and breathable. The waterproof TPU backing is what makes the leakproof claim credible.

NIXI Body Gracie Leakproof Thong — back view showing the thong back construction and how the VPL-free design sits smoothly under fitted clothing — The back view — a true thong back with no visible lines. Under fitted leggings, it's genuinely undetectable.

The sizing note — low-cut style, some customers prefer to size down — was useful. I ordered my usual size first and found it comfortable; I've since tried a size down and prefer the slightly more secure fit for training. Both work; it's a matter of preference.

First Wear at the Gym

NIXI Body Gracie Leakproof Thong — product lifestyle shot showing the thong in a gym or activewear context, demonstrating its suitability for exercise and active use — Designed for active use — the nylon elastane construction moves with you during exercise rather than shifting or bunching.

I wore the Gracie to a gym session on day two of my cycle — light flow, the kind of day where I'd previously either skipped the session or gone with a tampon and spent the whole time slightly anxious about it. I wore the Gracie alone, without any backup.

I did an hour of mixed training: weights, some cardio, a stretch session at the end. The thong didn't move. It didn't bunch. It didn't show through my leggings — I checked in the mirror before leaving the changing room and there was nothing to see. I was protected and I didn't think about it once during the session, which is the entire point.

I got home, rinsed it under cold water as recommended before washing, put it through a 30-degree cycle, and hung it to dry. It was dry by the following morning.

Three Months On

NIXI Body Gracie Leakproof Thong size chart — showing the sizing guide for the low-cut thong style with the recommendation that some customers prefer to size down — The size guide — the Gracie is a low-cut style and some customers prefer to size down for a more secure fit during exercise.

I now own three pairs of the Gracie. I use them specifically for the transitional days of my cycle — the first day or two and the last day or two — when I want protection without the bulk of fuller-coverage period underwear. They've been through repeated washing cycles without any loss of absorbency or change in fit.

NIXI Body Gracie Leakproof Thong — flat lay product shot showing the full thong from above, displaying the low-cut waistband and the integrated absorbent gusset construction — The flat lay — the integrated gusset is visible within the thong construction, showing how the absorbency is built in without adding visible bulk.

I've also worn them outside the gym — under fitted dresses, under tailored trousers, on days when I want the security of leakproof protection without any visible line. They work in every context. The invisibility under fitted clothing is real, not aspirational.

NIXI Body Gracie Leakproof Thong — detail shot showing the washable and reusable construction, highlighting the sustainable period product credentials and care instructions — Washable and reusable — better for you and the planet. The care routine is simple and the thong holds up through repeated cycles.

I no longer skip gym sessions at the start or end of my period. That's the whole story. Four years of inconsistency solved by a thong.

What's Actually Changed

My training is more consistent. That has downstream effects — on my fitness, on my mood, on the sense of routine that I find genuinely important for my mental health. None of that is dramatic, but all of it is real, and it traces back to having the right product for a specific problem I'd been tolerating rather than solving.

If you train regularly and you've been managing the start or end of your cycle with compromises that don't quite work, the NIXI Body Gracie Leakproof Thong is the solution I wish I'd found sooner. Find it in our Women's Underpants collection and browse the wider range in Lingerie and Clothing. It's also in Apparel & Accessories and our Latest Products if you're browsing what's new.

— Priya Nair-Chandrasekaran, physiotherapist and four-days-a-week gym regular, writing from a training schedule that is finally, properly consistent.