Citric Acid Is the Underrated AHA That Deserves Our Attention

There's no shortage of alpha-hydroxy acids in the skincare world. And while glycolic and lactic acid often get all the attention, there's another, very commonly-used AHA that deserves equal consideration. We're talking about citric acid, which has some unique properties and good-for-your-skin benefits that set it apart from other acids. Ahead, experts Gretchen Frieling, Ife J. Rodney, and David Petrillo, explain what makes citric acid so special, and why and how you may want to incorporate it into your skincare routine.

What Is Citric Acid?

"Citric acid is a type of alpha-hydroxy acid that's extracted from citrus fruits such as lemons, limes, oranges, and grapefruits, as well as other fruits such as berries," explains Rodney. It's also an incredibly common ingredient, plentiful not only in many types of skincare but also things such as food and household cleaners, and is even used as a preservative, she adds.

Benefits of Citric Acid for Skin

Because it is an AHA, citric acid offers the same types of exfoliating properties as any AHA would. But it also has a few additional benefits worth calling out.

• Acts as a chemical exfoliant: All alpha-hydroxy acids, citric acid included, work by helping to dissolve the "glue" that keeps dead cells stuck together on the surface of the skin. By promoting cell turnover and helping these dead cells slough off, it helps unclog pores, even out skin tone, and improve overall textures, says Frieling.
• Easily tolerated: What separates citric acid the most from other AHAs is its molecular size: "Citric acid's molecules are larger than those of glycolic acid, which is the smallest of all the AHAs, but they're also bigger than lactic acid, pyruvic acid, and tartaric acid," explains Petrillo. That means that it's harder for the skin to absorb the citric acid, which means it's weaker and less potent. But the upshot is that it may be much easier for someone to tolerate citric acid than it would be glycolic acid, Petrillo adds.
• Has astringent properties: Oily skin types, take note. Citric acid is a natural astringent, helping to dry out excess oil and leaving the skin feeling nice and clean, notes Rodney.
• Contains protective antioxidants: "Citric acid is unique compared to other acids because it also has antioxidant benefits," says Frieling. "External aggressors, such as sun damage, can wreak havoc on skin cells. Antioxidants like citric acid can help combat some of that oxidative stress to reveal brighter-looking skin."
• Helps maintain the skin's pH levels: Here's another unique feature. "With a natural pH of about 2, citric acid is an excellent pH balancer," notes Rodney. Why is that important? Keeping the skin's pH from becoming too alkaline helps maintain normal skin barrier function, explains Frieling. A well-functioning skin barrier is at the root of healthy, beautiful skin.

Side Effects of Citric Acid

While citric acid is considered gentler and more mild than others, it is still an acid, which means there's always some potential for irritation. This holds especially true for those with sensitive skin or an inflammatory skin condition, such as rosacea, notes Petrillo. Citric acid will also make your skin more susceptible to the sun, so it's imperative to be extra on top of your daily SPF game whenever you're using it.

How to Use It

Again, as is the case with many other acids, the experts we spoke with agree that it's best to follow particular product directions for application and usage. Citric acid is often paired with other acids—both AHAs and BHAs—because they all work together synergistically, but proceed with caution if you have sensitive skin. And avoid using any kind of physical exfoliant, such as a scrub or abrasive tools, at the same time, notes Petrillo. Similarly, if a retinoid is part of your skincare regimen, don't use it at the same time as citric acid. Use the citric acid in the morning and the retinoid at night, or alternate days.