The term “retinol” may be something that you are vaguely familiar with, or perhaps you’re already a die-hard fan. Regardless of your familiarity with it, retinol and retinoids remain a mistifying component of our daily regimen. They are, however, as important as a cleanser, moisturizer, and sunscreen. Yup. Just as important. More than Vitamin C or peptides. Here’s why:

Retinoids are a topical form of Vitamin A (usually they are formulated as serums) that promote cellular turnover, bringing forth younger cells to the surface of your skin. According to extensive clinical research, retinoids improve the appearance of fine lines and wrinkles by promoting the growth of more collagen (the structural protein in your skin that gives it that bounce), improve hyperpigmentation, sun damage, and even out skin tone. Essentially they are a miracle worker and along with sunscreen, most dermatologists swear by it.

So what is the difference between retinol, retinoids, Retin-A, retinoic acid?

Retinol is a form of retinoid, which are compounds that are or act similarly to Vitamin A. When retinoids (including retinol) are used they have to go through a process of conversion, using your skin’s enzymes to become retinoic acid, which is what creates the cellular change. Retinols are compounds that are at the first stage of conversion, while other retinoids, such as tretinoin (the generic name for Retin-A) are at the second stage. This is why retinoids generally are more effective than retinol – they take less time to deliver the same results. Tretinoin and some other retinoids are only available through a prescription from a dermatologist and therefore have been subjected to the FDA’s rigorous testing for safety and efficacy.

So, while retinoids are miracle workers, they do have a few things to keep in mind. First, they take a while to deliver visible results (at least 8 to 12 weeks, and 6 months for the full effect). They are also quite irritating – to get your skin acclimated to them, start using them only once or twice a week, gradually increasing the frequency with which you incorporate them into your daily regimen. Use them at night, since they increase your skin’s sensitivity to UV rays. That means that it’s important to use sunscreen in the morning, every day.