Here’s a fact: retinol is one of the most clinically-proven active ingredients around. Still, this potent skincare favorite seems veiled in mystery: who should be using it, when should you start, what’s it really doing — and once and for all, what do you call it?

Here, we debunk 9 of the most common retinol myths.

#1 Retinol, retinoid, retinyl, Retin-A: they’re pretty much all the same

While it’s true that these “R” ingredients all fall under the same vitamin A umbrella, they’re not identical. Some are much stronger than others, based on how much work your skin cells must do to convert the ingredient to make it useful. This is a measure known as bioavailability.

Here’s a breakdown of the “R’s,” with ingredients listed from highest to lowest potency:

• Retinoid: a class of active ingredients derived from vitamin A.
• Retinoic acid: the most bioavailable (i.e. directly useable) substance that binds to skin cell receptors.
• Retin-A: a brand name of the generic prescription drug tretinoin, formulated with pure retinoic acid.
• Retinol: a substance that’s converted by the skin into retinoic acid in two chemical reactions.
• Retinyl: found preceding palmitate, acetate, or linoleate, these ingredients require at least 3 conversions to become retinoic acid.

#2 You should wait until your 30s to use retinol

Retinoids were initially developed to treat acne, and have been used successfully for decades by people in their teens and twenties. Researchers subsequently discovered the anti-aging capabilities of these vitamin A derivatives.

Cell turnover begins to slow down as early as our mid to late twenties — so starting retinol before you see any signs of aging is a smart idea. SLMD Retinol Resurfacing Serum is great for keeping breakouts in check, evening out skin tone, and minimizing fine lines in acne-prone skin.

#3 Retinol is the ultimate exfoliant

It’s common to see retinoids described as exfoliating the skin — but that’s not exactly accurate. Exfoliants loosen the bonds between dead skin cells, causing them to slough off and reveal newer skin beneath. Retinoids bind to skin cells, prompting them to speed up the rate of cell turnover, creating new skin faster and helping to prevent dead skin buildup.

This results in accelerated desquamation: losing those dead, outer skin cells more quickly.

#4 Only certain skin types can tolerate retinol

Redness, peeling, flaking: the initial irritation that can result from retinoid use has led to the misconception that retinol is too strong for some people. While everyone’s skin is different, it’s likely that any issues during the first few weeks of use will subside once your skin gets used to the product.

Typically, this irritation period lasts 2-3 weeks, and can be improved by gradually dialing up to the recommended dose.

#5 You can’t apply retinol within 30 minutes of cleansing

This advice may be true for some people — but it’s not a hard-and-fast rule. Damp skin is more porous, which means that active ingredients can better penetrate the skin. If you don’t experience irritation when you apply retinol right after cleansing, there’s no reason to wait.

#6 Retinol thins your skin

This one is partially true — but it’s not like it sounds. Remember that your skin is made up of many layers, with the tough stratum corneum making up the outermost layer. These dead cells tend to build up as we age, but retinol speeds up the rate at which new skin cells form — which in turn encourages those outer dead cells to slough off. This thins the stratum corneum, so skin appears newer and fresher.

Studies have also shown that retinol stimulates the dermis (that’s the layer directly beneath the epidermis) to produce more collagen. That’s the protein responsible for giving skin structure. As a result, skin becomes measurably thicker.

#7 Don’t use retinol near your eyes

Likely related to the myth above, many people believe that the skin around the eye area is just too delicate for retinol. But dermatologists agree that as long as you don’t get product close enough to actually get into the eye (which can cause irritation), you should definitely take advantage of its ability to minimize crow’s feet and help even tone.

#8 You can’t combine retinol with alpha or beta hydroxy acids

Yep: there’s such a thing as product overload. Using several retinol products, or applying it more than once daily, can cause irritation. So can exfoliating too frequently. On the other hand, the right combination of active ingredients can really maximize their effectiveness: when you remove some of the dull, dead outer skin cells with an acid like glycolic or salicylic, your retinol product can penetrate better.

Dr. Sandra Lee (aka Dr. Pimple Popper) recommends her best-selling SLMD Salicylic Acid Cleanser, gentle enough to use every day. It’s important to listen to your skin: if you’re experiencing redness, peeling or flaking beyond the typical 3-week initiation period, try dialing down your routine a bit. Use retinol every other night, and/or limit your exfoliant use to morning or just a couple of times weekly.

#9 It takes about a month for retinol to work

This one probably came about based on the 28-day skin cycle: if it takes about 4 weeks for a new skin cell to push its way to the surface and slough off, that’s how long you need to wait to see skincare results. Fact is, retinol can take a lot longer — estimates range from 3 to 12 months — to demonstrate its full effectiveness.

That doesn’t mean it’s impossible to see improvement in less time — some people put visible changes at about 6 weeks — but it does mean you should be patient before throwing in the towel on your retinol product.

Keep in mind that a prescription tretinoin product is going to work faster, because it’s more bioavailable. However, the potential for irritation is correspondingly greater as well.