Derm DMs: How many skincare acids should I use in my routine?

Acids have infiltrated almost every category of skin care products. Right now on my dressing table, cleanser, toner, essence, serum and exfoliating pads they all contain some form of hydroxy acid (i.e. AHA or BHA). These ingredients are effective and provide great benefits to the skin, but they can also cause dryness and irritation if used too often or incorrectly. While it's tempting to want to stock up on all kinds of foods that contains acid (and clearly I know this from experience) you don't want to overdo it.

I recently spoke with Dr. Patricia Wexler, a board-certified dermatologist in New York, to find out how many exfoliating products can be used in one treatment. Read her expert advice. 

Can products containing acids be layered?

There really is no yes or no answer here; The amount of exfoliation your skin can handle depends on several factors. First, it's your skin type, says Dr. Wexler. Acne-prone, oily skin usually tolerates acids better than dry or sensitive skin. However, Dr. Wexler notes that "acids should be used in moderation" regardless of your skin type. 

Other factors that may affect your tolerance are: percentage of acid you use and whether you use a barrier-strengthening moisturizer. "There are essential oils on your skin that you don't want to remove," says Dr. Wexler. Removing these essential oils not only causes dehydration and leaves the skin barrier vulnerable to damage, but it can also cause your skin to produce more sebum to compensate. The moisturizing ingredient Dr. Wexler recommends using after exfoliation is hyaluronic acid. Despite its name, this ingredient is not an exfoliating acid, so it can be used safely with AHAs and BHAs. 

One acid that can usually be used daily (especially for people with oily skin) is salicylic acid (BHA). "Very few people are allergic to it, and it's great at helping to tighten and unclog pores," she says. This can be especially helpful for keeping your skin clear if you often wear a protective mask. 

If you want to use another acid, such as an AHA, to correct uneven tone or texture, Dr. Wexler recommends using a mild acid and using a moisturizing product right away. For example, you can use a daily cleanser containing salicylic acid (try Vichy Normaderm PhytoAction Deep Cleansing Gel), and then serum with glycolic acid (for example, L'Oréal Paris Derm Intensive 10% Glycolic Acid) (daily or two to three times a week, depending on your skin) and then apply a moisturizer such as CeraVe Moisturizing Cream. It is formulated with ceramides and hyaluronic acid to protect the skin barrier. 

How to know if you're overexfoliating

Redness, irritation, itching, or any adverse reactions are all signs of over-exfoliation. “Nothing you use should cause these problems,” says Dr. Wexler. If you experience any of these effects, delay exfoliation until your skin has healed and then reevaluate your exfoliation regimen and skin concerns. It is important to pay attention to your skin and note how it reacts to certain percentages of acid and frequency of use. It's always best to start small and slow (i.e. low acid percentage and low frequency of use) and work your way up as your skin needs. When in doubt, consult a dermatologist for an individualized plan.