Every female runner knows the drill. Race morning, period shows up uninvited. Suddenly you’re doing mental math about tampons, timing, and what shade of running shorts is safest. It’s exhausting, and it has nothing to do with the actual running.
Kiprun, Decathlon’s running label, has teamed up with French menstrual-tech brand Smoon to put that problem to rest. Their new Run 900 short has a fully integrated period brief sewn right in. One piece of kit. Done.
What’s actually going on inside the shorts
The inner brief works through three layers: a moisture-wicking surface that keeps things dry, an absorbent core rated to around two tampons’ worth of flow, and a waterproof membrane underneath to handle any leaks or odor. Kiprun says that adds up to 12 hours of continuous protection — long enough for most training runs, marathons, and the post-race beer.
The outer shell is the same ultra-light fabric used in the existing Run 900 Light, coming in at just 111 grams for a size medium. There’s a zipped back pocket, a small key pocket inside, and heat-bonded seams to keep chafing at bay. The components are OEKO-TEX certified — independently tested and verified free of chemicals harmful to skin.
At €49.99, it costs roughly the same as a decent pair of running shorts on their own — and covers your entire race day kit below the waist.
Five years to get here
This wasn’t a quick product pivot. Decathlon and Smoon spent five years developing the collaboration, and Smoon’s credentials are solid — the company has moved over 250,000 menstrual swimsuits in the past three years. They know how absorbent technology behaves when bodies are moving fast and getting wet.
The running application brought its own challenges. The brief had to stay put at pace, not bunch, not shift, and not add any noticeable weight or bulk. Kiprun tested prototypes with real runners and iterated before landing on the final design.
“I see too many women stop running for fear of leaks or discomfort,” said Dr. J. Durand, a sports medicine gynecologist. Maintaining regular exercise through the full cycle, she noted, helps regulate premenstrual symptoms and supports mental wellbeing — a good reminder that this isn’t just a gear story.
