As the crusade for cleaner beauty products continues, skin care ingredients that were once considered standard are rightfully being called into question.

Take parabens, for example. Now that we know the once-popular preservatives are also potentially carcinogenic endocrine disruptors, beauty brands are removing them from their formulations and slapping “paraben-free” stickers on everything. The same for phthalatessulfates, formaldehydes, and a whole host of other possibly dangerous ingredients.

While most experts support the removal of parabens, phthalates, sulfates, and morefrom skin care, one group of ingredients that’s made the “free from” lists is still up for debate: silicones.

On one side of the argument, you have those who say silicones make skin look healthier without actually contributing to its overall health.

On the other side, you have those who say silicones aren’t technically harmful, so there’s no harm in keeping them in skin care products.

Which side is science on? Well, both. Kind of. It’s complicated.

First, what exactly are silicones?

“Silicones are a group of semi-liquid substances derived from silica,” Dr. Joshua Zeichner, a board-certified dermatologist with Zeichner Dermatology in New York City, tells Healthline. Silica is the main component of sand, but that doesn’t mean that silicones fall under the “natural” umbrella. Silica has to go through a significant chemical process to become silicone.

Silicones are best known for their occlusive properties, which is a fancy way of saying that they form a barrier-like coating on the skin that’s resistant to both water and air. Zeichner likens it to a “breathable film.”

“Used medically, silicones have been proven to help heal wounds and improve scarringTrusted Source,” says Dr. Deanne Mraz Robinson, a board-certified dermatologist and member of the Healthline advisory board. “They have long been used in burn units because they can uniquely heal and protect while allowing the wound to ‘breathe.’”

Basically, their occlusive nature blocks lacerations from interacting with the outside environment, ensuring the wound stays in its own little healing “bubble.”

“They also have a unique texture, giving skin care products a slick feel,” Zeichner says. This sums up the main role of silicones in serums and moisturizers: They make for easy application, lend a velvety texture, and often leave skin looking plump and smooth, thanks to that filmy coating.

So, why don’t people like them?

Honestly, all of that sounds pretty great. So, uh, why don’t people like silicones? There are a few reasons.

The argument: The benefits of silicones are only superficial

The verdict: Unless you’re dealing with an open wound on your face, silicones don’t provide any tangible benefits to the skin. “In cosmetic products, they mostly deliver a pleasant-feeling carrier base,” Mraz Robinson says. Think thick, blendable serums and moisturizers.

Silicones smooth over any rough patches and lock in moisture. So, while silicone-filled serums and moisturizers might make your face look and feel nice in the moment, they don’t contribute to the long-term health and improvement of your skin. As soon as you wash the product off, you wash away the benefits.

The argument: These ingredients are harder to wash off and get stuck in pores

The verdict: “Silicones are hydrophobic,” Mraz Robinson says. In layman’s terms: They repel water.

For this reason, silicone-based products don’t rinse away easily. The oil cleansing method was practically invented to help dislodge silicone particles from pores. So, if you do slather on the silicones every once in a while, oil cleanse or double cleanse before bed to keep your complexion free and clear.

The argument: They cause breakouts

The verdict: It turns out, there’s a downside to silicones’ occlusive abilities. Sure, they keep environmental aggressors out, but they also lock in some not-so-great substances.

“For acne-prone patients, silicones can act as a ‘barrier’ and trap oil, dirt, and dead skin cells, making acne worse,” Mraz Robinson says.

Dermatologists maintain that if you’re not typically prone to breakouts, you shouldn’t have an issue. If your pores already tend toward clogs, though, it might be a good idea to skip the silicones.

The argument: Silicones mess with product layering

The verdict: Fans of 10-step routines, or even three-step routines, for that matter: Put down the silicone serum and slowly back away. Silicones may block subsequent ingredients from reaching the skin, rendering anything applied after a silicone product pretty much useless.

“They sit on the surface of the skin and allow the ingredients [underneath] to sink in while simultaneously creating a protective barrier on the skin’s surface,” Mraz Robinson explains. This could, theoretically, be great as the last step in your routine, but using silicones any earlier in your routine could present a problem.

The argument: They’re basically just filler

The verdict: While the majority of silicones have been shown to be safe for topical application, they’ve also been shown to be… a lot of fluff.

“Overall, I like to avoid inactive ingredients, or ‘filler’ ingredients,” says Mraz Robinson. “For everyday use, I would say avoid them when you can, but for condition-specific use, like topical wound healing, don’t be afraid.”

The argument: Silicones aren’t eco-friendly

The verdict: Even if all the above arguments aren’t enough to make you say buh-bye to silicones, this one might be: Silicones are bioaccumulativeTrusted Source. Once they’re rinsed down the drain, they contribute to the buildup of sludge pollution in oceans and waterways, and don’t break down for hundreds of years.

How to tell if silicones are in your skin care products

More and more brands are opting out of silicones every day, so the easiest way to ensure your skin care products are filler-free is to look for a label that says “silicone-free” or “free from silicones” (or some more inventively-worded variation thereof).

You can also scan the ingredients list on the back of the product packaging. Anything that ends in -cone or -siloxane is a silicone.

Other common names for silicone in cosmetics include:

  • dimethicone
  • cyclomethicone
  • cyclohexasiloxane
  • cetearyl methicone
  • cyclopentasiloxane

It’s definitely not necessary to include silicones in your skin care routine. But according to dermatologists, it’s not totally necessary to eliminate them, either — at least, for the sake of your skin.

If you’re concerned about green, natural, or otherwise eco-friendly skin care, though? Go silicone-free, stat.