If you’ve spent any time digging through the mountains of beauty blogs out there, you’ve probably come across the term active. (Like, how can you add actives to your regimen, or how to pick actives that can address acne, hydration, or brightening concerns.) But what actually are actives?

The short answer: An active is the ingredient in a product addressing whatever skin concern it’s meant to target. Whether they work for you is not always clear—until you try them. But there’s a lot more to actives than just that. So, here’s what dermatologists want you to know about working with actives and how to find one that’s most likely to help you.

In general, an active is something that contains an active ingredient.

“When I look on the back of a bottle and it says the active ingredient, that to me means the chemical or molecule in that product that is doing what the product says it’s supposed to do,” John G. Zampella, M.D., assistant professor in the Ronald O. Perelman department of dermatology at NYU Langone Health, tells SELF. If you’re getting a cleanser that is claimed to treat acne, for example, the active ingredient is what actually treats the acne, possibly something like salicylic acid, he explains. So, an “active” skin-care product is simply anything that has an active ingredient (and not every product does).

But these aren’t just ingredients we think do something—we have a pretty darn good idea that they’ll be effective. “An active ingredient has been proven in a lab by research to change the skin in some way; it’s an ingredient that has data behind it,” Emily Newsom, M.D., a board-certified dermatologist at Ronald Reagan UCLA Medical Center, tells SELF. And claims about the effectiveness of those products are regulated by the FDA to reflect that level of certainty.

Just because a product doesn’t have an active ingredient doesn’t mean it’s useless, though. The inactive ingredients, meaning any of the ingredients that are not considered actives by the FDA and regulated as such, are also important. In many cases, the product is simply not designed to treat a specific condition even if it does a great job of cleansing or moisturizing your skin. The inactive ingredients are also often key in helping deliver the active ingredient to your skin (the most common inactive ingredient is water, after all). Certain inactive ingredients may also be irritating to those with sensitive skin or allergies (e.g. a botanical extract), Dr. Zampella says—so you shouldn’t ignore them on a label.

There are a few main categories of active-containing products.

These are the most common types of topical actives you’ll come across that address specific skin issues:

  • Signs of aging: SPF-boosting ingredients (e.g. zinc oxide, titanium dioxide, avobenzone, oxybenzone), vitamin A/retinoids, vitamin C, vitamin E.
  • Dryness: hyaluronic acid, vitamin E.
  • Pigmentation issues: kojic acid, AHAs, BHA, hydroquinone, vitamin C.
  • Acne: vitamin A/retinoids, salicylic acid, benzoyl peroxide, azelaic acid.
  • Rosacea: various antibiotics, azelaic acid, sulfur.
  • Psoriasis: steroids, vitamin A/retinoids, vitamin D, salicylic acid, urea, lactic acid, anthralin, tacrolimus, pimecrolimus.
  • Eczema: steroids, tacrolimus, pimecrolimus.

You can find active ingredients in both prescription and over-the-counter products.

Some skin products containing actives are considered drugs or medication and require a prescription. A product that is claimed to actually change the structure of your skin (like some antiaging products) or treat the symptoms of a condition (like eczema, psoriasis, or rosacea) is usually considered a drug by the FDA, which means it comes with a specific set of regulatory guidelines and an approval process involving clinical trials before it can be sold.

Some ingredients, like salicylic acid, are almost always treated as drugs, which means they have to be made according to a specific formula and called out on the product label in a very specific way, including the concentration and the ingredient’s purpose. But often it’s the way a product is marketed—including its intended use, what the consumer perceives it to do, and what the packaging claims it will do—that determines which category the FDA puts it in.

So, a product might say it can “reduce the appearance of” skin concerns such as wrinkles or redness or otherwise make them “less noticeable”—without specifically saying it treats the underlying condition associated with those issues. In these cases, the FDA treats them like cosmetics rather than drugs. Cosmetic ingredients aren’t tested by the FDA before they’re sold, so the responsibility for them to be safe and effective rests on the manufacturer. Specifically, cosmetics are defined as products “for cleansing, beautifying, promoting attractiveness, or altering the appearance,” and they are required not to mislead consumers with their claims, otherwise the FDA may take action.

Here’s where it gets really confusing: Whether or not a product lists the active as an active ingredient on the label comes down to whether or not it’s considered a cosmetic or a drug. A skin-care cosmetic product may contain the same active ingredient as a product that’s considered a drug, but it won’t list the active ingredient in question as an active ingredient on the label, but rather as an ingredient—even if it is advertised on the front of the packaging. This is due to the wording of the claims around the ingredient.

For instance, a face wash containing salicylic acid may be considered a drug and list it as an active ingredient if it claims to actually treat or manage acne. If it’s a cosmetic, it may just list salicylic acid among its many ingredients.

You might find the same active ingredient in a drugstore option, a luxury option, and a prescription.

And, importantly, the expensive or prescription options may or may not be superior to a drugstore product with the same active ingredient. Prescription medications and luxury skin-care products can cost hundreds of dollars, but “the same active ingredient might be in a product that costs 10 bucks,” Dr. Newsom says. “Just because a celebrity uses it and it costs a lot more doesn’t mean it works any better.”

For instance, you can get a prescription for azelaic acid that comes in 15 percent (Finacea) and 20 percent (Azelex) concentrations, which may cost somewhere in the ballpark of $300 to $400 if your insurance doesn’t cover it. Or you can buy a 10 percent version online that doesn’t claim to “treat” anything (and doesn’t break out azelaic acid as an active ingredient in a drug facts box, but does list it in the long list of ingredients) for a fraction of the price.

In some cases those differences in the concentration or overall formula of the product matter; in others it might matter only a little bit or not at all. For example, “the 10 percent [version of azelaic acid] hasn’t been tested in a clinical trial,” Dr. Zampella says. “But the active ingredient we know is regulated by the FDA. Is it still going to have some effect? I think the answer is yes.” (As a reminder, though, actives aren’t the only ingredients in a product and the inactive ingredients may be crucial for delivering the active ingredient to your skin. So it’s always worth talking your choices through with your derm.)

When it comes to benzoyl peroxide, as another example, research suggests that a 2.5 percent concentration is basically just as effective at treating acne as a 10 percent version, Dr. Zampella says. “Depending on what you’re treating, the concentration might not be that important.” But maybe for your individual skin type and situation, only the 10 percent gets the job done. And if we’re talking about topical steroids, which are used to treat psoriasis and eczema, the dose definitely makes a difference, Dr. Zampella says.

Concentration isn’t the only thing to think about, though. Sometimes an ingredient may have been approved to treat an issue in an oral form, but it’s sold over the counter in a topical form, Dr. Newsom says. This is the case with a newer ingredient called tranaxemic acid (TXA) that has been shown to help with melasma when taken orally—but there isn’t solid evidence that it’s effective topically.

The big takeaway here is that even if a product contains an active ingredient, that doesn’t necessarily mean it has a concentration or formula that puts it at the same efficacy level as that of a prescription option—so it may or may not work as effectively (and we may simply not know if it will work). Talk to your derm about your specific skin issues and the active you’re curious about, and they can help determine whether a prescription drug is necessary, or if an OTC recommendation will suffice.

You can always ask your derm for help understanding an ingredient list.

The back of a skin-care product is usually a labyrinth of long words, and all you want is for it to work. But it’s worth having a grasp on what the main ingredients do and what the product may be able to achieve for your skin before you buy so you don’t waste your effort and money. According to our experts, it’s especially important to pay attention to:

  • The active ingredient
  • The concentration of the active ingredient
  • Any inactive ingredients you might be allergic or sensitive to
  • The way claims are worded on the packaging

Ultimately, you should absolutely feel empowered to parse the ingredients you’re putting on your skin. And, of course, if you have any questions along the way, your dermatologist is the best resource you have for making sense of it.

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