If you want to get the most out of your retinoid product and avoid potential irritation, understanding the different types of retinoids and which one works best for your skin is a must. These vitamin A derivatives are potent actives, so they are very effective in targeting a wide array of skincare concerns. However, this also makes them not the easiest ingredients to play with, and using retinoids wrongly is definitely something your skin won’t like. Besides, there are quite a few forms of retinoids that address different concerns. Hence, assessing what type of retinoid you need increases the chances that your product will truly deliver.

What are retinoids?

Retinoids are vitamin A derivatives often used to treat acne and photoaging thanks to their ability to regulate cell growth, promote collagen production, accelerate wound healing, reduce wrinkles, and improve skin texture.^[1][2] Studies also point out that retinoids have antibacterial, anti-inflammatory, and antioxidant activities and are great bleaching agents effective for skin discoloration.^[3] Retinol, retinyl palmitate, and tretinoin are all types of retinoids, but they are not all equal in strength and tolerance rate.

While retinoids naturally come from animal sources, those found in skincare formulations are mostly synthetically made. 

Prescription vs. over-the-counter retinoids

There are prescripted retinoids that include the strongest forms (tretinoin, tazarotene, isotretinoin) and are used as a generic medication for moderate and severe skin conditions. On the other hand, skincare products contain over-the-counter retinoids (retinol, retinaldehyde, and retinyl esters) that are gentler and work great for preventing and correcting mild conditions.

How retinoids work

Retinoids work by encouraging cell turnover and inducing collagen production. However, for retinoids to affect your skin cells and provide these benefits, they must first be converted by special enzymes into the active form of vitamin A (retinoic acid). 

Each type of retinoid has to go through one, two, or three conversion steps to become retinoic acid, and the potency of a retinoid is highly affected by the number of conversions it has to go through. Retinoids with the closest proximity to retinoic acid are the strongest, while those with three conversion steps apart are the least effective (but also the gentlest).

Tretinoin is the most potent form of retinoids because it doesn’t need to undergo any conversion since it already is the active form of vitamin A. Retinaldehyde and retinol, on the other hand, must be turned by enzymes into usable retinoic acid, so they are less effective and milder.

The different types of retinoids

Different types of retinoids are used in skincare, classified according to their strength, the risk of irritation, and what skin conditions they target. 

Tretinoin

Tretinoin, known as Retin-A, is the topical form of pure retinoic acid available only as a prescribed treatment. Since it’s already active, tretinoin does not need to be converted by the skin enzymes, so it’s one of the most potent types of retinoids — 20 times more potent than retinol.^[1] It’s usually used in concentrations of 0.025% to 1% as a topical solution to treat severe acne as well as reduce signs of photoaged skin, including wrinkles and dark spots. As the strongest form of retinoid, tretinoin is also the most irritating, so you should use a regenerative moisturizer after tretinoin to increase your skin’s tolerance. Your dermatologist should also align you with everything you need to know to avoid sensitivities when prescribing tretinoin.

Isotretinoin 

Often known as Accutane, isotretinoin is the oral form of pure retinoic acid and the most effective type of retinoid for severe acne. It turns out it’s the only treatment that impacts all of the major causing factors of acne, affecting sebum production, inflammations, and bacteria.^[4] According to studies, in low dosages (0.5–1.0 mg), isotretinoin can clear 90% of acne, and the results usually take 16 to 30 weeks to appear. P.S: Isotretinoin carries no anti-aging effects when taken orally.

Tazarotene 

Tazarotene, brand name Tazorac, is a third-generation retinoid and the first topical retinoid developed for the treatment of psoriasis — a condition that causes itchy, dry patches.^[5] Tazarotene is also approved by the U.S. Food and Drug Administration (FDA) for acne treatment (only in 0.1% strength) and proved effective for photoaged skin.^[6][7] Unlike other retinoids, tazarotene doesn’t convert to retinoic acid once it enters the skin but to its biologically active form of tazarotenic acid.

Adapalene 

Adapalene is a synthetic retinoid derived from naphthoic acid that’s available in both over-the-counter and prescription forms.^[1] In fact, it’s the first prescribed retinoid made available over-the-counter since it’s less irritating than tretinoin. Adapalene also does not need to be converted to retinoic acid before it becomes active, so it’s very effective. But unlike tretinoin, topical adapalene has no effects on aging skin, being mostly studied for its benefits in acne treatment. So if you don’t like going into the prescription-strength territory and your only concern is acne, adapalene is one of the best forms of retinoids to consider.

Retinaldehyde 

Among the different types of retinoids, retinaldehyde is the most potent OTC form since it requires only one conversion to get into the active form of vitamin A. According to several studies, it offers similar benefits to pure retinoic acid for reducing the signs of photoaging, and it’s also effective for breakouts, skin discoloration, and uneven texture.^[1][3] However, compared to retinoic acid or tretinoin, retinaldehyde acts more gently on the skin and is less likely to irritate. Plus, it’s easily accessible since you can find it in all sorts of products, including creams and serums.

Retinol 

Retinol is the most popular form of retinoids used in skincare, and one of the best researched ones for sure. Yet, the thing with retinol is that it’s significantly less potent than other types of retinoids, more precisely 20 times less potent than tretinoin.^[1] This is because retinol needs to be converted twice — once to retinaldehyde and then to retinoic acid — to become active and provide benefits. The worrying part is that this conversion process is usually slow, resulting in only 5% of retinol being converted to retinoic acid.^[8] Regardless, there’s a lot of scientific evidence that proves retinol is effective for wrinkles, acne, dark spots, and lack of firmness, despite its slow conversion rate.

Related: 9 Best Retinol Creams for Beginners To Start Your Retinoid Journey

Retinyl esters

Retinyl esters are the most abundant retinoids present in the body, resulting from binding retinol molecules to fatty acids. The most common retinyl esters used in skincare include retinyl propionate, which is formed by binding retinol with propionic acid, and retinyl palmitate, which results from retinol and palmitic acid. Retinyl esters are usually much gentler and more stable than retinol but also less effective. They’re best suited for people who can’t tolerate other forms of retinoids or have reactive skin.