Can You Use Glycolic Acid and Retinol Together?

Glycolic acid and retinol are two of the most popular anti-aging ingredients featured in skincare, but how do you decide which one is right for you? More to the point, is it ok to use both at the same time? Can you use glycolic acid and retinol together? Or would it just be one giant skin disaster waiting to happen?

The short answer is that it really depends on your skin type and what you are trying to achieve! Let’s look at why this is…

Glycolic Acid

Glycolic acid is an alpha hydroxy acid (AHA) that is made from the sugar cane plant and weakens the bonds between dead skin cells on the surface of the skin, enabling exfoliation to take place. It has the lowest molecular weight of all the AHAs which means that it is better able to penetrate the skin and can be more effective. However, this means that it also has the potential to cause more skin irritation.

AHAs, such as glycolic acid, are commonly used to treat the signs of sun-damage, such as pigmentation, fine lines and wrinkles, enlarged pores, and uneven skin tone. In addition, they can be useful in the treatment of acne.

Retinol

Retinol is a derivative of vitamin A that can increase the rate of skin cell turnover and renewal, reduce sun damage, boost collagen production, improve the appearance of wrinkles, reduce pigmentation, and increase skin hydration. However, initially, retinol can cause irritation and dryness of the skin by damaging the skin’s protective barrier which increases the amount of water lost from the skin.

Can You Use Glycolic Acid and Retinol Together?

Glycolic Acid and Retinol Optimum pH Levels

Working out which skincare ingredient’s can and can’t be combined together can be utterly headache-inducing. Are differing pH levels an issue? Are you going to end up with angry irritated skin?

To make matters worse, the relationship between glycolic acid and retinol is a complicated one. In theory, the pH levels at which they are optimally effective are different and they are both ingredients that have the potential to cause skin irritation – even separately!

For starters, the optimal pH for retinol activation is somewhere between 5.5 and 6, while glycolic acid is most effective at a much lower pH (less than 3.5).

So what happens to glycolic acid at a higher pH? Well, some research suggests that glycolic acid is still effective at a pH of 4.4 ^[1], which is still lower than what is apparently optimal for retinol.

However, the skin’s surface pH is naturally acidic anyway, with pH levels ranging from anywhere between 4.7 and 5, which means that retinol is always used at a pH level that is less than optimal without its effectiveness being reduced.

This suggests that it is a myth that glycolic acid and retinol render each other useless due to differing pH levels.

But what about irritation potential?

Glycolic Acid and Retinol Mechanism of Action

Both glycolic acid and retinol increase the rate of skin cell turnover but in different ways. Retinol encourages the production of new skin cells and increases the rate that these cells travel to the surface of the skin.

It’s a common misconception that retinol has an exfoliating effect because it can cause the skin to flake and peel. However, this is a sign of damage to the skin’s barrier and dehydration.

In contrast, glycolic acid acts at the surface of the skin to weaken the bonds between dead skin cells in order for them to be shed faster.

This means that glycolic acid and retinol actually compliment each other and may enhance the effects of the other.

This seems to particularly be the case when it comes to the treatment of acne and acne scars.

Can You Use Glycolic Acid and Retinol Together to Treat Acne and Acne Scarring?

Multiple research studies have found that the combination of glycolic acid and retinol, either in the same product or applied separately, can be well-tolerated and a complimentary and effective acne treatment.

For example, a combination of retinaldehyde and glycolic acid significantly reduced the number of spots and pimples after 1 – 3 months of use with very little skin irritation ^[2]. The same combination has also proved useful at preventing and treating the post-inflammatory hyperpigmentation (PIH) left behind after acne clears ^[3].

Other research provided patients with 0.025% retinoic acid and 12% glycolic acid and were told to mix half a fingertip of each together and apply every day. 91% of patients saw an improvement in their atrophic (pitted) acne scars, while 85% of patients experienced improvements in PIH ^[4].

The improvement in pitted scars suggests that the combination of retinol and glycolic acid may increase collagen production and, therefore, offer anti-aging benefits.

Potential Issues When Combining Glycolic Acid and Retinol

One thing to bear in mind, especially for those with acne-prone skin, is that both glycolic acid and retinol can cause skin purging. This is an initial breakout of spots and pimples that are caused by the use of products that increase skin cell turnover. These spots and pimples would have appeared eventually, however, it can be alarming when they all come to the surface of the skin at once.

In the same vein, those with dry or sensitive skin may experience irritation when using either glycolic acid or retinol and this may be enhanced when combining the two together. If you experience flaking and peeling, you may want to reduce the frequency of use of either/both glycolic acid and retinol or use them on alternate nights.

Summary – Can You Use Glycolic Acid and Retinol Together?

Overall, glycolic acid and retinol make a great skincare pairing as long as you don’t experience any skin irritation. If your skin is prone to irritation, then you may want to consider alternating the nights that you use glycolic acid and retinol.

In addition, reducing the frequency of use to every other night may slow the purging process for those with acne-prone skin.

A common misconception is that glycolic acid and retinol can’t be combined together due to their differing pH levels. However, this is a myth and both can be very effective at the skin’s natural pH level.

So yes, you can use glycolic acid and retinol together – you just need to listen to your skin!

References

1. DiNardo, J., Grove, G. & Moy, L. (1996). ‘Clinical and histological effects of glycolic acid at different concentrations and pH levels’, Dermatol Surg., 22(5), 421-424. Available at: https://pubmed.ncbi.nlm.nih.gov/8634803/
2. Poli, F., Ribet, V., Lauze, C., Adhoute, H. & Morinet, P. (2005). ‘Efficacy and safety of 0.1% retinaldehyde/ 6% glycolic acid (Diacneal) for mild to moderate acne vulgaris’, Dermatology, 210(Supp 1), 14-21. Available at: https://www.karger.com/Article/Abstract/81498
3. Katsambas, A. (2005). ‘RALGA (Diacneal), a retinaldehyde and glycolic acid association and post-inflammatory hyperpigmentation in acne – a review’, Dermatology, 210(Supp 1), 39-45. Available at: https://www.karger.com/Article/PDF/81501
4. Chandrashekar, B., Ashwini, K., Vasanth, V. & Navale, S. (2015). ‘Retinoic acid and glycolic acid combination in the treatment of acne scars’, Indian Dermatol Online J., 6(2), 84-88. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375771/