Using retinoids and an AHA (e.g. glycolic acid) or BHA (e.g. salicylic acid) actually diminishes the effectiveness of both ingredients. So how can you benefit from the potential anti-aging effects of each ingredient? To find the answer, I consulted with the site of Dr. Leslie Baumann, M.D., a practicing dermatologist and the co-founder and chief of the Cosmetic Dermatology department at the University of Miami School of Medicine. According to Dr. Baumann:
“Your question about order is a great one. Retinoids should not be mixed with BHA (i.e., salicylic acid) or AHA (i.e,. glycolic acid) because the BHA and AHA can inactivate the retinoid. Always use retinoids at night because the sun can also make the retinoid less effective.”
Of course, as would be expected from Dr. Baumann, this makes perfect sense.[Read more: Can You Really Use Retinoids with AHA, BHA, and L-ascorbic Acid or Not?]
Daytime AHA/BHA Products
Since AHA/BHA make your skin more sensitive to the sun, and so more susceptible to UV damage, you should always use AHA/BHA under a broad-spectrum UVA/UVB sunscreen with an SPF of at least 30. You should reapply it frequently and, if you can manage it, avoid the sun between 10 a.m. and 4 p.m.
These are some AHA or BHA products I like:
Paula’s Choice Exfoliating 2% BHA Lotion ($33.95, Amazon.com)[RELATED: Spotlight On: Alpha-Hydroxy Acids]
Nighttime Retinol Products
Some nighttime retinol products that I like from lowest concentration to highest:[Read More: 11 Things That You Never Knew about Retinol and Retinoids – Until Now]
Remember, the higher the concentration of retinol, the higher the risk of skin irritation. Studies show that 0.5 is the ideal concentration to start at for minimum irritation with maximum benefits. Start with a small application every two to three nights, and slowly work up a tolerance so that you may use it nightly. Ask you develop a tolerance, you can use higher concentrations of retinol. Most importantly, remember that it’s always best to consult your dermatologist before you start using any new product or ingredient.[RELATED: What is Retinol Metabolism?]
Using retinoids and AHA/BHA products at the same time can lower the effectiveness of both ingredients. But if you use them at separate times during your routine — AHA/BHA in the morning and retinoids at night — you can get the benefits of both without decreasing the effectiveness of either.