The big question: is it bad to re-wear workout clothes?
The short answer is yes, it is as they can harbor bacteria that can cause acne and folliculitis.
"From a dermatologist’s standpoint, I would be worried about fungal folliculitis—when the hair follicles become inflamed, caused by a bacterial or fungal infection—when re-wearing sweaty workout clothes," adds Caren Campbell, MD, a San Francisco- and Napa-based board-certified dermatologist. Pores open up when you are exercising and sweating and dirty clothing could push growing bacteria, yeast, and fungus into the skin.
What you need to consider before deciding to re-wear.
You should consider how much you actually sweat in the clothes before you re-wear them. For instance, if you participated in a high-intensity class that left your bra and leggings drenched, it isn't wise to re-wear those clothes. If you have the option of choosing used clothing that you used for less-sweaty endeavors, choose those instead.
It will also depend on the piece of clothing itself, for example, you can re-wear non-sweaty gear like a sweatshirt but some sports clothes like bras and tight shorts shouldn't be re-worn after being sweat in.
Campbell says it's best to wash these in warm water with detergent to kill bacteria and yeast that can cause infections, irritation, and breakouts. It's especially vital to avoid re-wearing workout clothing if you have any open wounds, cuts, or rashes. Be careful with that! These open areas can develop an infection if bacteria harbored in dirty clothing come into contact.
The potential side effects of re-wearing workout clothes are several skin conditions, such as acne, folliculitis, intertrigo, tinea versicolor.
Yeast can especially grow under your breasts or in the groin area if you re-wear workout clothing. These warm, moist areas are more susceptible to bacteria and yeast growth and can cause recurring infections. If you must re-wear workout clothing, make sure it's not a bra or bottoms.