Get the most out of your skincare routine with these power combos.

Like peanut butter and jelly or chips and salsa, there are certain skincare ingredients that just work better together. Don't get us wrong, they're still great on their own (just like you could eat your chips plain and they'd still be delicious). But in the ongoing quest to make your skincare routine as effective as possible—not to mention get the most bang for your buck from the products you're using—knowing which ingredients play nicely together can be helpful. On the flip side, there are certain pairings that don't mix, and can end up either inactivating one another and/or leading to some serious skin irritation, neither of which you want. To keep things simple, consider the below a helpful 'cheat sheet' of ingredients that work especially well together—and those that don't.

1 Do Mix: Vitamin C + Sunscreen

It hopefully goes without saying, but wearing sunscreen 365 days per year, rain or shine, is arguably the most important thing you can do to maintain healthy, beautiful skin. Once you've nailed that step, consider giving your SPF a little extra boost by layering a vitamin C-based serum underneath your sunscreen, suggests Kavita Mariwalla, MD, a board-certified dermatologist in New York City. No matter how diligent you are about applying sunscreen, it's inevitable that your skin is still going to get some amount of sun exposure. Vitamin C is a powerful antioxidant that works to scavenge the damaging free radicals that form as a result, acting as a second line of defense and extra layer of protection.

2 Do Mix: Vitamin C + Ferulic Acid and/or Vitamin E

Speaking of vitamin C, you can up its benefits even further by searching for a serum that pairs it with ferulic acid and/or vitamin E. "Vitamin C is great for helping address sagging, textural irregularities, and skin discoloration," says Morgan Rabach, MD, a board-certified dermatologist in New York City, co-founder of LM Medical, and assistant professor of dermatology at Icahn School of Medicine at Mount Sinai. The only problem? It's notoriously unstable, which is where these two other ingredients—which, like vitamin C, are also powerful antioxidants—come in. "Vitamin E and ferulic acid keep the vitamin C more stable and prevent it from degrading," she explains. Plus, all three work synergistically when it comes to delivering those protective antioxidant benefits.

3 Do Mix: Retinoids + Peptides 

Dr. Mariwalla says it's a great idea to use both a retinoid- and peptide-based night cream at bedtime. "You get the collagen-building effects of the retinoid, but it also works to improve the penetration of the peptide cream, which can help improve skin's firmness," she explains. Plus, many peptide creams contain plenty of emollients, hydrating ingredients that can help counteract the irritating side effects that often come with using a retinoid. Use the retinoid first (just a pea-size amount), then top it with the peptide cream.

4 Do Mix: Retinoids + Hyaluronic Acid

Similarly, pairing a retinoid with a hydrating hyaluronic acid-based moisturizer is another good combination, according to Dr. Rabach. Retinoids are great because they can help tighten pores, decrease oil production, and get rid of dead skin. However, all of this can make the skin dry and flaky, she explains. That's where hyaluronic acid comes in, a choice moisturizing ingredient that can ward off that unwanted dryness. And while it was once thought that applying a moisturizer before a retinoid would render the latter inactive, that's not the case, says Dr. Mariwalla. Apply a light layer of the hyaluronic acid cream or serum first, followed by a pea-sized amount of the retinoid.  

RELATED: Yes, You Can Use Retinol on Dry Skin - Here's How

5 Don't Mix: Retinoids + Any Acids

Retinoids are super effective, but that potency comes with a high potential for skin irritation and increased skin sensitivity. That's why you definitely shouldn't be using retinoids at the same time as skincare acids—such as alpha- and beta-hydroxy acids—which also increase sensitivity, warns Dr. Rabach.  And while it's not an acid, Dr. Mariwalla adds that you also shouldn't combine retinoids with benzoyl peroxide;  it will make the retinoid less effective. If you do want to use both types of ingredients, use the AHAs, BHAs, or benzoyl peroxide in the morning, and always save the retinoid for evening. "Retinoids can make your skin more sun sensitive so make sure you're only using them at night," notes Dr. Mariwalla.

6 Don't Mix: Beta-Hydroxy Acid + Alpha-Hydroxy Acid

To the point of acids, it's best not to use products with beta-hydroxy acids and alpha-hydroxy acids at the same time, cautions Dr. Mariwalla. (Salicylic acid is the most common BHA whereas glycolic and lactic acid are popular AHAs.) The two categories aren't meant for layering and can cause too much dryness and irritation, she says. That being said, they can work well together—so long as they're formulated and blended correctly. If you want to reap the benefits of both, seek out one singular product that uses the two types of acids simultaneously—and is specially formulated to minimize the likelihood of irritation—rather than layering two separate products on top of one other. 

7 Don't Mix: Niacinamide + Vitamin C

Whereas vitamin E and ferulic acid make vitamin C work better, niacinamide can decrease the efficacy of vitamin C several fold, notes Dr. Mariwalla. That being said, niacinamide is a great skincare ingredient that delivers a litany of benefits (it's an effective skin-soother and moisturizer, just to name a few) so it is still worth working into your routine. Her suggestion? Apply vitamin C in the morning, under sunscreen, and reserve niacinamide for evening use.