TikTok makeup users all over the world are now using calamine lotion as a primer, claiming the product keeps their makeup on longer. It has now become a popular beauty hack, but dermatologists are taking issue with its use.

Calamine lotion has been traditionally used for medicinal purposes, being used to soothe itches, irritated skin, rashes, and sicknesses that affect the skin such as chicken pox. Azadeh Shiradazi, a dermatologist practicing in the San Diego area, says that it doesn’t make sense to use this product, as it can cause dry skin and damage the skin barrier. She urges people to think before using this product too much, saying overuse can result in “severe irritation and worsening of scars.” Many dermatologists say that at the very minimum, don’t use calamine lotion daily.

This trend has popped up with reports of small shortages of calamine lotion. Some parents have even reported having trouble finding the product for their children suffering from chickenpox. Even though experts have expressed their wariness, calamine lotion might continue to hold its appeal because it’s cheap; in the U.K. it costs under two pounds.