Heat rash happens when sweat gets trapped under the skin, often in warm or humid weather or when a baby is dressed in something too heavy. Muslin is cotton woven in an open, loose weave, so there are small gaps running through the fabric that let air pass through instead of holding it against the skin. That openness is what makes muslin feel light and breathable, and it's part of why so many parents reach for it in hot climates. It also softens more with every wash, so it gets more comfortable over time, and it dries quickly after a wash or a sweaty day.
Our Epic pieces are double-layer muslin cotton, pre-washed before they ever reach you so they're already soft on the first wear instead of stiff out of the bag. We sew with flat seams so there's less rubbing against the skin, and we finish everything with child-safe dyes rather than harsh treatments. To keep the fabric working the way it should, wash cold on a gentle cycle, skip the fabric softener (it coats the fibers and cuts down on breathability), and tumble dry low or just hang it to dry. Sizes run from newborn up to about 4 years, so you can stick with muslin as your baby grows.
Muslin is gentle on sensitive skin in terms of comfort, it's soft, light, and less likely to feel hot and heavy against your baby. But it isn't a fix for heat rash or any other skin condition, and we wouldn't want you to rely on clothing alone if your baby is struggling with it. If your baby has a rash that won't clear up, keeps coming back, or looks infected, please talk to your doctor or paediatrician. They can tell you what's actually going on and how to treat it, and in the meantime, dressing your baby in something loose and breathable like muslin is one small thing that can help keep them comfortable.