“An ampoule is a small, single-service—most often glass—tube containing a supercharged serum with the highest concentrations of active ingredients,” says Ava Shamban, MD, a board-certified dermatologist based in Beverly Hills, Calif. “The term ampoule is derived from a word meaning ‘small package.’” Ampoules are, indeed, similar to serums in that they target specific skin concerns, but they’re not quite the same. There are three key factors set ampoules apart:

They feature ultra-high concentrations of active ingredients.They’re housed in small, single-use vials to provide the perfect dose every time.They’re sealed in air-tight containers to reduce oxidation.

“Ampoules are great for targeting skin concerns that your current skincare lineup can’t tackle on its own,” notes Charlotte Cho, esthetician and founder of Soko Glam. “Due to their high concentration formulas of potent ingredients, they really hone in on what exactly it is you want them to do, whether it be blemish control, pigmentation fading, or hydration.” As for where they fall in your regimen, ampoules are applied after your toner and/or essence, but before your preferred moisturizer. When in doubt, always apply your skincare products in order of thin to thick.

How to Choose the Best Ampoule

Ampoules come in a variety of formulations, depending on the skin concern you want to target. For example, if an ampoule contains a high level of vitamin C, it can help fade hyperpigmentation. Or if an ampoule is formulated with concentrated cica (aka centella asiatica), its purpose is to help soothe an irritated skin barrier. “If you’re interested in finding an ampoule that’s formulated to help fight blemishes, look for BHAs [beta hydroxy acids], AHAs [alpha hydroxy acids], and tea tree water on an ingredient list,” adds Cho. “For soothing ampoules that are suited for sensitized, dehydrated, and sensitive skin, you’ll want to look for an ampoule formulated with cica, mugwort, or houttuynia cordata.” For ampoules that can help control oil and reduce the look of pores, Cho says that an ampoule with a high concentration of niacinamide (vitamin b3) will be your best bet. Dr. Shamban notes that some supercharged ampoules are designed specifically for post-treatment care after getting an in-office procedure, such as lasering or a peel. Because the skin barrier is temporarily “compromised” after these procedures, the ampoules are better absorbed.

Best Ampoules to Try

Now that you know why you need an ampoule, we found the best ampoule for every skincare concern below.