A recent survey by Pour Moi, which included 1,500 women in the UK, found that 5% either never or rarely wear underwear to the gym. However, discussions on online forums suggest the number may be higher. On platforms like Reddit, users have shared their experiences of working out without underwear, often citing discomfort from tight leggings or excessive sweating. Some participants in the r/womensfashion and r/yoga communities said they prefer to go "commando," while others expressed discomfort with the idea. The debate has gained attention following the Hyrox scandal, in which athlete Joanna Wietrzyk competed with visible fecal matter on her legs. This incident raised concerns about gym hygiene. Some gym-goers argue that going commando can be unhygienic, with one Reddit user stating, "This is the reason I wipe gym equipment down before and after I use it. Commando just sounds horrible to me." Stephen Roland, founder of Fortify Personal Training, argues that wearing underwear in the gym is a hygiene issue, as less fabric to absorb sweat means more sweat ends up on the machines. Dr. Asiya Maula, director and GP at The Health Suite, says underwear can provide a useful layer of moisture absorption, especially if made from breathable, natural fibers like cotton. She warns that without underwear, sweat, bacteria, and discharge come into direct contact with the fabric, increasing the risk of irritation, folliculitis, or yeast and bacterial infections, including UTIs in those prone to them. Anwen Davies, a certified personal trainer and gym product developer, notes that odor is a significant concern, as polyester worn during intense exercise becomes far smellier than cotton. Underwear acts as a buffer layer that absorbs much of the sweat before it seeps into gym clothes. Dr. Rupa Parmar, GP and medical director of Midland Health, says there's nothing inherently unhygienic about exercising without underwear, provided gym clothes offer enough coverage. She notes that bacteria thrive in warm, moist conditions, and an extra layer of fabric can actually give them a better environment to grow in. Looser gym wear without underwear is sometimes recommended to keep the area cooler and drier. Ultimately, whether one wears underwear or not, gym etiquette and hygiene are essential. Dr. Parmar advises wiping equipment before and after use, using a clean towel as an extra barrier, and washing hands after using shared equipment. Lewis Pearce, owner of Boxstop x Boiler Room Fitness, emphasizes that clothing may become an issue if it affects the experience of others or creates a hygiene issue. Denise Chakoian, a certified fitness trainer, agrees that it's less about whether someone is technically wearing underwear and more about whether their clothing provides adequate coverage and works for the movements they're doing. If clothing is loose, sheer, or revealing during certain exercises, she might suggest a different option to avoid an uncomfortable situation. Dr. Maula concludes that neither choice is wrong, but it's the habits around them that really count. Washing workout gear, showering after exercise, and choosing breathable fabrics are what matter most in maintaining hygiene and comfort during gym sessions.