The Difference Between Retinol, Tretinoin, Glycolic Acid and Kojic Acid

Retinol, Tretinoin, Glycolic Acid and Kojic AcidHere at, we get a lot of questions about different skincare ingredients and what they can do for your skin.

To help you out, we’re going to briefly go over four of these anti-aging ingredients that we get the most questions about.  Namely retinol, tretinoin, glycolic acid and kojic acid.

Let’s get started…


The namesake of this site, retinol is a popular skincare ingredient that’s a derivative of vitamin A.

And if you haven’t heard by now, decades of clinical research has shown that retinol does quite a few amazing things for your skin.

It speeds up skin cell turnover, fades pigmentation, shrinks pores, rebuilds collagen and elastin and retexturizes the surface of the skin.

So what does all that mean?

It means retinol users can achieve younger, clearer-looking skin with less fine lines and wrinkles.  Who doesn’t want that?

And one of the best things about retinol, in addition to all the great benefits for your skin and appearance, is the fact that it’s available over-the-counter in a variety of different products.

So you don’t have to go to a doctor or mess with constant prescriptions.

Overall, retinol is considered by dermatologists as one of the best, most proven ingredients when it comes to anti-aging and better-looking skin.


If you’ve ever had severe acne, there’s a good chance you’ve heard of tretinoin.

Tretinoin is simply the generic name for the prescription drug Retin-A (as well as a few others).

It’s basically a retinoid that’s pure retinoic acid.

We don’t want to complicate things too much here, but retinoic acid is what’s responsible for all the benefits of not only tretinion but also retinol.

It basically increases skin cell turnover, which leads to many of the benefits we discussed above in our summary of retinol.

So what’s the difference between tretinoin and retinol?

Tretinoin is pure retinoic acid while retinol is stored in the skin and then converted to retinoic acid.

The difference is subtle but has a huge impact on two things– how quickly they work and the side effects.

With tretinoin, the skin-improving benefits will happen faster than with retinol, but the side effects of redness, burning, itching and peeling, will usually be greater.

With retinol, it takes longer to see results, but the side effects we just mentioned are usually considerably less.

So retinol basically works as a much weaker, better-tolerated version of tretinoin.

And with retinol, you don’t need a prescription; with tretinoin, you do.

Ok on to the next ingredient…

Glycolic Acid

Shifting gears a little bit, glycolic acid is more of an exfoliator than retinol or tretinoin, and a completely different ingredient.

(As a side note, you should know that exfoliating is extremely important for healthy, clearer, younger-looking skin.)

Glycolic acid is considered an AHA or Alphahydroxy Acid.

It’s derived from sugarcane and is a fruit acid similar to the other AHAs lactic, citric, malic, and tartaric acid.

That’s all fine and well but what does glycolic acid do for the skin?

Like many exfoliators, it helps to sweep away dead skin cells on the topmost layer of skin to reveal newer, younger skin cells underneath.

Because of this effect, it can also be used for acne treatment as well as anti-aging.

Glycolic acid is available in quite a few different OTC products, so you don’t need a prescription.

It can also be used, in much higher strengths that’s what’s available OTC, as a peel performed in a medical or skincare office.

Kojic Acid

The last anti-aging skincare we’re going to look at is one that many people aren’t familiar with– kojic acid.

Kojic acid is a natural substance found in fungi like mushrooms and rice malting.

It’s used primarily as a skin lightener, similar to what hydroquinone’s used for.

Kojic acid is good for minimizing skin discoloration, especially in those with a darker complexion.

It works by curtailing the production of melanin in the topmost layer of skin (it doesn’t penetrate very far however).

Like retinol and glycolic acid, kojic acid is available in OTC creams and products and doesn’t require a prescription.

Ok that about sums it up…

Hopefully you have a little more clarity on these ingredients and what they can do for your skin.

If you have severe acne, tretinoin is probably a good choice.

If you’re looking for a proven, all-around anti-aging treatment, you can’t do much better than retinol.

If you want a good exfoliator, perhaps try a product that has glycolic acid in it.

And finally, if you’re looking to lighten discoloration, kojic acid may be helpful.

Whatever you choose, be sure to check back here for the latest in skincare and detailed product reviews!

Click here for our list of the best retinol creams.