There's no shortage of alpha-hydroxy acids in the skincare world. And while glycolic and lactic acids 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, Gretchen Frieling, MD, a triple board-certified dermatopathologist in the Boston area, dermatologist Ife J. Rodney, MD, founder of Eternal Dermatology in Fulton, Maryland, and cosmetic chemist David Petrillo, founder of Perfect Image, explain what makes citric acid so special, and why and how you may want to incorporate it into your skincare routine.
Type of ingredient: Alpha-hydroxy acid
Main benefits: Promotes exfoliation and skin cell turnover and is also a good source of antioxidants.
Who should use it: Citric acid is generally considered safe for all skin types, except for those with known allergies or especially sensitive skin, says Frieling. However, it can be particularly beneficial for those with oily skin.
How often can you use it: This is largely dependent upon the particular product you're using, but generally speaking, about two to three times per week.
Works well with: It's often paired with other alpha-hydroxy acids and beta-hydroxy acids, though this can potentially cause more irritation for those with sensitive skin.
Don't use with: Avoid using citric acid at the same time as any retinoid, as this can lead to irritation and redness, says Rodney. If you want to use them both in one day, use the citric acid in the morning and the retinoid at night, she adds.
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. However, it's worth noting that 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. And 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 do all work synergistically together, 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.
The Best Products With Citric Acid
Both Rodney and Frieling recommend this affordable and very effective exfoliant. "The formula uses a potent mix of AHAs, such as citric acid, and BHAs such as salicylic acid. Use it once a week to help fight breakouts and achieve bright, even-toned skin," says Frieling. (But she does caution that it's likely too intense for those with sensitive skin.)
Using a rinse-off product, such as a cleanser, is a great way to ease into a new active ingredient, given the minimal contact time it has with the skin. Petrillo likes this gel wash, which gently exfoliates (credit the citric acid in the mix) and smoothes skin's texture while also effectively removing dirt.
See spots run. "This non-hydroquinone, non-retinol formula effectively treats dark spots and skin discoloration using a combination of natural skin lighteners, including citric acid," says Rodney of another one of her product picks.
Regarding the point about citric acid being a choice ingredient for those with oily skin, here it's found in a toner that is ideal for post-cleansing to get an extra-deep clean. Plus, the citric acid in the formula helps bring the skin to a neutral pH before applying any other products, and the antioxidant properties help offer added defense against environmental aggressors, notes Frieling.
"This is a beautiful serum for anyone looking to tackle both signs of aging and clogged pores. It combines AHAs, such as citric acid, along with pure vitamin C to combat signs of free radical damage and to promote cell turnover and collagen production," explains Frieling. She suggests using it in the morning, under sunscreen, of course, to help achieve a bright and youthful complexion.
Both Team Byrdie and Rodney are fans of this cult-classic. While it does contain a very potent blend of both AHAs (citric acid included) and BHA, it's formulated at a special pH in order to prevent redness and irritation. Instead, it simply leaves your skin as fresh and radiant as, well, a baby's. Rodney suggests using it weekly for the best results.
Rodney recommends this serum, a good option for those with sensitive skin. It contains citric acid, but at a very low concentration, and is loaded with hydrating and soothing ingredients: Think sweet almond oil and sunflower seed oil.