Also known as tretinoin, retinoic acid is the most bioavailable retinoid. In other words, “Retinoic acid doesn’t need to go through any conversions, so it is readily available and faster-acting” than other retinoids, according to Sheila Farhang, MD, board-certified dermatologist and founder of Avant Dermatology & Aesthetics. And because of that, Dr. Chang says, it’s typically available only in prescription form — mostly commonly as Retin-A.
Retinol, to be precise, is the alcohol formulation of vitamin A, not to mention the version most commonly used in skin-care products, according to Dr. Chang. “Retinol has been shown to improve tone and texture, dyspigmentation, dryness, and fine lines,” she says. But there’s a catch. “It is less irritating than tretinoin, but also 20 times less potent because it needs to convert into retinoic acid.”
That doesn’t mean over-the-counter retinol isn’t effective, however. “Retinol can benefit skin at levels as low as 0.01 percent to the maximum recommended level of 1 percent,” Robinson tells Allure — great news for newcomers who may want to start at a lower level and work their way up in retinol strength.
Retinyl palmitate, the ester of retinol combined with palmitic acid, is also frequently found in skin care. Retinol esters, in general, are precursor molecules to retinol, which means they need to be broken down first into retinol and then into retinoic acid. “Therefore, they are less potent than retinol,” Dr. Chang says.
And finally, there’s retinaldehyde or retinal aldehyde. Because “[retinal] can be directly converted to retinoic acid and is more stable than retinol,” David Kim, MD, a board-certified dermatologist at Idriss Dermatology in New York City explained, it’s closer in efficacy to retinoic acid than retinol is.
What can retinol do?
You’ve probably heard that almost everyone can benefit from using retinol, and that’s not an exaggeration. “[Retinoids] are keratolytics, which means they increase skin cell turnover and are known to stimulate collagen synthesis,” Dr. Farhang says.
So what does that mean for your skin-care concerns and goals? If you’re looking to diminish common signs of aging and sun damage by smoothing skin texture and evening skin tone, using a retinol product is highly recommended by experts. “It can help reduce the look of wrinkles, as well as smooth, even out, and firm skin,” Robinson tells Allure.