TikTok has become the hub for beauty tips, some safe and expert-backed and others, well, not so much. One buzzy trend that may not be worth your time: mixing your retinoid with your body lotion. While some may think this is the answer to maintaining youthful body skin, that’s not necessarily the case. Countless derms have weighed in on this trend—here’s what they have to say. 

Why you shouldn’t mix retinoids into your body lotion. 

The word retinoid is an umbrella term for all vitamin A derivatives, including over-the-counter and prescription-grade products. Retinoids stimulate collagen production, increase cell turnover, and brighten the skin; because of these functions, retinoids are a great option for those looking to ease fine lines, fade dark spots, and even treat some forms of acne. 

The trend in question, specifically, seems to focus on retinoids that you can only get with a prescription, most notably tretinoin. In these videos, creators empty their entire tretinoin tube into a tub of body lotion as a DIY retinoid-infused formula.

A few skin care experts, including board-certified dermatologists Angelo Landriscina, M.D., FAAD, and Lindsey Zubritsky, M.D., FAAD, have deemed the trend unnecessary and ineffective. Yes, you should always moisturize when using a retinoid, but this may not be the best way to do so. “When you’re doing this, you’re playing cosmetic chemist at home,” Zubritsky explains, which isn’t such a smart idea.

Why doesn’t this trend hold up? As Landriscina says, “Tretinoin is extremely unstable. It breaks up super easily, so that’s why it’s kept in containers that are really good at keeping out air and light.” So by emptying out your entire tube (i.e., exposing it to both air and light), you’re essentially wasting the product. 

When you destabilize the tretinoin, Zubritsky explains, “[You’re] not only making it ineffective, but it can cause more damage and harm to the skin.” While you can use retinoids on the body, this makeshift method isn’t going to serve you. 

Instead, Zubritsky explains, apply the tretinoin first (read: Leave it in the container it came in), and then follow up with a hydrating body lotion or cream. You can also invest in a retinol body lotion specifically formulated for this purpose. But if you’re using prescription-grade products, it’s best to consult your dermatologist before deciding to apply the retinoid to your body in the first place. 

Surprise, surprise—not every skin care hack on TikTok is worth your time and money. By emptying the contents of your retinoid into a tub of body lotion, you’re exposing it to air and light, making the product unstable. This means your retinoid may now be less effective and more harmful to the skin. Instead, apply the retinoid first and follow up with a moisturizer. Still curious about how to use a retinoid? Check out our full guide.