Now that you get why it is important to moisturize and what ingredients to look out for, it’s time to dive into what not to do with moisturizers.

Like with most beauty products, there are some common mistakes to watch out for. For example, using too much moisturizer can be counterproductive. “Younger skin (under 25) usually produces plenty of NMF, so adding extra moisturizer isn’t always necessary,” says Dr. Obagi. Just consider your skin’s needs and keep it light. When in doubt, it is always best to consult a dermatologist in person.

Another common mistake is applying moisturizer at the wrong time. Hatzistefanis suggests applying moisturizer as the last step in your routine, right after serums, “while your skin is still a little damp” to seal everything in. During the day, follow it up with your favorite SPF.

Though there is some debate about whether you should apply SPF before moisturizer if you’re using a chemical sunscreen, Dr. Ibrahim says it’s not something to stress over. “In general, as long as SPF is on the skin, you are safe,” he says. “Some dermatologists argue that it’s better to apply chemical SPF before applying moisturizer to allow SPF ingredients to penetrate into the skin better due to an old dogma. It used to be believed that chemicals absorb into the skin so they can ‘neutralize’ rather than reflect UV rays, and it’s no longer true as both mineral and chemical filters reflect UV rays. What’s most important is the film that forms over the skin. I still suggest SPF being the last skin care applied to avoid dilution and moving the sunscreen around.”

Dr. Ibrahim also advises against layering multiple products with the same active ingredient, which includes acne-fighting principles like salicylic acid, benzoyl peroxide, and retinoids. “When it comes to acne-fighting ingredients, be careful to not overuse them as they can be irritating and drying to the skin,” he says.

“Outside of acne-fighting ingredients, for teens wanting to incorporate active ingredients, look for ingredients with antioxidant properties that can help protect the skin against UV and environmental damage. Think vitamin C, green tea, and plant extracts that contain polyphenols like ginseng,” he continues.

While Dr. Ibrahim says in general teens can use actives and there’s no particular ingredient they should avoid, the key is not overusing ingredients and products for the sake of it. “[Teens] have young, healthy skin already. While ingredients like peptides won’t hurt, there’s just no reason to spend money on ingredients that the skin doesn’t need,” he explains.

“In short, the key for teenage skin: prevention and protection. Don’t overdo anti-acne ingredients, incorporate antioxidants, and if you have acne, use a retinoid like Differin Gel that’s both anti-acne and anti-aging.”

Dr. Tripathi explains it further. “Moisturizer and SPF is all teens need, unless treating something like acne,” he elaborates. “In that case, I recommend salicylic acid and tretinoin, separated, or benzoyl peroxide, however, it’s best to consult a derm for your specific concerns.”