These days, beauty counters are piled high with stacks and stacks of the latest creams, serums, and SPFs that all promise to whisk skin concerns and prevent new ones from coming on. In no surprise to anyone, super-concentrated active ingredients are highly covetable, and that’s why ampoules, a Korean beauty staple, are now making their way to the United States.

Ampoules are highly concentrated active serums that are specifically designed for one-time use. “The amount and container size are strategically for preserving the pureness of the product,” explains Julie E. Russak, MD, a New York City dermatologist. “There are no added fillers, the product often features one main star ingredient, and, because of the way it’s packaged—it’s usually for one single use—so it isn’t compromised by the effects of being exposed to the environment.”

This is especially important for ingredients like retinol and vitamin C, which David Lortscher, MD, a board-certified dermatologist and CEO of Curology, says are unstable and easily degrade when exposed to light and air. Howard Sobel, MD, a New York dermatologist adds that ampoules, such as Dr. Barbara Sturm Hyaluronic Ampoules ($145) and Natura Bisse Diamond Instant Glow ($90), are of particularly high quality given not only their small, air-tight vials or capsules, but also the fact that they ensure that you’re applying the right amount of product to your face.

What do ampoules do?

Beyond the ingenious packaging, let’s talk about the benefits of actually adding them into your routine. “Ampoules offer the purest form of active ingredients at a prescribed amount so skin absorbs exactly what it needs,” Dr. Russak explains. “Usually, ampoules are marketed to address one specific skin issue at a time; say, dry skin or dull skin.”

To state one single result of an ampoule would be to assume that all ampoules are meant to do the same thing, and they’re not. While they’re all pure and stable, the actual effects of any given ampoule comes down to the ingredients within it. Common ingredients found in ampoules include hyaluronic acid, ceramides, retinol, and vitamin C, so check out which one you’re getting before you slather it onto skin and expect one effect. “Depending on the ingredient, it can help brighten, hydrate, or plump fine lines and wrinkles,” says Dr. Sobel.

One thing to note? “Ampoules tend to have a short lifespan as they are often formulated without preservatives,” Dr. Sobel reminds. “Make sure to use them up before their expiration date.”

How are ampoules different from serums?

TBH, they’re not all that different from serums. According to Lily Talakoub, MD a dermatologist in McLean, Virginia, ampoules are simply potent serums in high concentrations without fillers, and this helps to extend their shelf life.

That’s not to say that ampoules and serums are the same thing though. “Serums are multi-use and can sometimes be compromised in temperature and efficacy,” Dr. Russak explains. Ampoules, on the other hand, are more like targeted boosters that don’t concern themselves with the possibility of oxidation.

Dr. Lortscher notes that ampoules are typically not part of a daily routine—though that doesn’t mean they can’t be used every single day. “Serums and oils tend to contain multiple ingredients designed for product balance or lower concentrations designed for everyday use; ampoules may give a greater degree of customization or control,” he explains.

Given their potency, you might wonder if these can be used in conjunction with other products, and the answer is yes. “Layer [the ampoule of your choice] between your cleansing and serum step,” says Dr. Sobel. “You can also skip your normal serum and go straight into moisturizing to seal all the active ingredients into your skin.”

What’s more, you can even add your ampoules into your favorite moisturizers, serums, and oils. “Ampoules are customizable, and the appeal is that the consumer can create a customizable cocktail of precise prescription-like care for the individual skin need,” Dr. Russak says.

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