When you’re shopping for a face mask, you’ll find that there’s one for practically every skin concern out there. This is great news when you consider all the skin-boosting possibilities that can happen within a 20-minute masking treatment. But anyone who’s slathered on masks to no avail has one question: Which skin conditions are best served by face masks and which ones should you reserve for your serums?

“Masks are a huge part of the skin-care market,” says Rachel Nazarian, MD, a New York City-based, board-certified dermatologist, explaining that they offer benefits through prolonged contact of active ingredients on your skin. “This process enhances the penetration of those active ingredients.” She’s also a fan of the product category because it’s so representative of self care and “encourages the need to stop and sit.” In other words: You get to relax and benefit from a complexion boost. Win-win.

That said, there are some skin conditions that leave-on products are best suited for. “For major skin issues like severe acne or rosacea, I would not depend on a short-contact mask to greatly improve [flare-ups],” says Dr. Nazarian. New York City-based board-certified dermatologist Melissa Kanchanapoomi Levin, MD FAAD agrees, noting that the skin benefits of face masks tend to be “minimal if anything.” You won’t notice as much of a change, for example, if you use an “anti-aging” face mask with retinol as you would from using a retinol—an active ingredient that’s been studied to better your complexion after regular use (rather than from a one-and-done treatment)—every single day. “Though masks can be effective in fighting signs of aging, keep in mind that oftentimes the longer an ingredient has contact with the skin, the more effective it can be,” says Dr. Nazarian. “A leave-on cream or serum would be superior from this standpoint.”

Also okay to skip? Charcoal masks. “I’m not a huge fan of these for any kind of dramatic improvement,” Dr. Nazarian says, noting that charcoal is great for removing oil, but that’s a “temporary perk” that won’t leave a lasting improvement to your overall skin health. If you want to spend your beauty bucks wisely, Dr. Nazarian recommends face masks for boosting hydration, fading hyperpigmentation, and helping to diminish breakouts, all of which you can notice improvement with weekly use. (Of course, it’s not like other masks are pointless—they’re just not your best bet if you’re looking for lasting results.) Now: Keep scrolling for what to look for when shopping for your masking treatment of choice.

For moisturizing TLC

“If you do want to mask, I recommend them only if you want them for hydration purposes,” says Dr. Levin, who’s a fan of sheet masks made of hydrogel or biocellulose for allowing active ingredients to penetrate better, like the Image Skincare Hydrating Hydrogel Sheet Mask ($9). Dr. Nazarian recommends looking for face masks that contain hyaluronic acid, squalane, or ceramides, which “allow your skin to rebuild itself with the building blocks for retaining and drawing in moisture,” she says. Her fave is the Neutrogena Moisturizing Hydro Boost Hydrating Hydro Gel Mask ($3), which all skin types can use. “The primary ingredient in this is hyaluronic acid, which hydrates and draws water in,” she says.

For pimple help

Masks aren’t exactly your best bet if you’ve got serious or cystic acne since the pimples are deeper below the skin’s surface, but they can help you out with regular ol’ zits (like whiteheads, when the pus is ready to be sucked out). Dr. Nazarian prefers face masks with sulfur for getting the job done. “It’s naturally antibacterial and decreases redness, and many oily-type and acne-prone people find it useful in improving the quality of their skin,” she says. “I find it to be a really effective and efficient ingredient if you’ve got oily skin.” Her tip? Try the Proactiv Skin Purifying Mask ($38), which also has tea tree oil and vitamin E “which aid in improving old acne marks and stains,” she says. Also great is the Sunday Riley Saturn Sulfur Acne Treatment Mask ($55), because its sulfur levels are strong, and they’re combined with zinc to further banish excess oil plus niacinamide for redness (niacinamide, or vitamin B3, strengthens the skin barrier, which results in less redness and irritation when faced with environmental stressors).

For reduced pigmentation

Hyperpigmentation takes a lot of time and patience to get rid of. But incorporating a weekly face mask for the spots can speed things up, says Dr. Nazarian. “You can decrease the production of the pigment, or melanin, with certain enzymes, such as licorice root extract, azaleic acid, vitamin C, and kojic acid,” she says. “You can also use ingredients that stimulate cell turnover, such as glycolic acid or other alpha and beta hydroxy acids.” If you’re prone to irritation, though, she recommends only using these masks occasionally—or she recommends the Biossance Squalane + Vitamin C Rose Oil Mask ($48) since the squalane and rose oil “make it more tolerable for sensitive skin.” I’m also a fan of the Tata Harper Resurfacing BHA Glow Mask ($65), which uses pomegranate enzymes as a gentle exfoliant-slash-antioxidant for sloughing off dead skin cells and brightening, plus white willow bark extract (a natural BHA) to clear pores.

If dark spots are your nemesis, here’s how to get rid of hyperpigmentation, according to a derm. And this is what to know about proper inflamed acne treatment.