Should you steer clear of this ingredient altogether or hoard every product that has it listed on the label? (Spoiler: While not harmful, we believe you should treat it with caution.) Board-certified dermatologist Dendy Engelman, M.D., agrees: “It’s popularly used in hair and skin care products as a smoothing and occlusive ingredient,” she says. “You may be able to recognize the presence of dimethicone in your products by the silky-smooth texture that it adds.” Essentially, it helps the formula to feel and perform more luxuriously. Engelman says it’s also used to create a protective barrier on the skin that blocks external agents like arid air and pollutants from reaching the skin while locking in moisture. In fact, one study found that a majority of skin care products use dimethicone for its moisturizing capabilities1—while it doesn’t deliver any benefits from a skin-health perspective, per se, it forms an occlusive layer to keep moisture in and helps keep the surface of the skin soft and smooth. However, there are a few reasons even water-soluble silicones can get a bad rap—one of the most commonly cited is because of its occlusive properties. Although, Engelman adds that dimethicone can irritate those with sensitive skin since silicones can cause irritation; and for those with acne-prone skin, it can create the perfect environment for breakouts. “Breakouts can occur when silicone builds up on the skin’s surface and traps bacteria, dirt, and pollutants in, clogging your pores,” Engelman warns. She continues that it can also interfere with natural processes like sweating and releasing unwanted dirt and bacteria from the pores since it creates a film over the skin. As Ron McLaughlin, vice president of research and development at Living Proof, previously told mbg about silicone buildup in hair care: “The obvious drawback of all this is that you end up with hair that gets weighed down or greasy, so you are more likely to shampoo and style more often. This perpetuates what we call the cycle of damage. The more you wash and style, the more damaged your hair is, so the more you will feel like you need to reach for a silicone to get that soft feeling again. It’s a vicious cycle.” Fu and Lu add, from a formulator perspective, dimethicone is a great ingredient to include for its silky texture: “It can help create a beautiful moisturizer suitable for oily skin types as well as create fantastic conditioners that really help to protect the hair.” Again, just be mindful that it can be difficult to remove and causes buildup over time since it does create a film over the skin and hair. And if you do find that you’re experiencing an allergic reaction or breakouts from this ingredient, it’s probably best to avoid it and talk to your dermatologist or hairstylist. There’s also the argument that the sort of things you put on your skin should be beneficial—instead of filler or sensorial additives. This is an argument we can certainly get behind, as there are many products out there formulated without silicones that use occlusive materials with additional skin-supporting properties (things like natural oils and butters). Ultimately, the choice is yours—and we just want you to be informed about the things you put on your skin.