Citric acid is an alpha hydroxy acid found naturally in citrus fruits like lemons and oranges. In skincare it plays two roles. At exfoliating strengths it helps loosen the bonds between dead surface cells so they shed more easily, and at the low levels used simply to adjust a formula's acidity, it does not exfoliate at all.
Research has classified citric acid as both an AHA and, at very low pH, a mild beta hydroxy acid, giving it a somewhat broader exfoliating action than some other fruit acids. It is also a recognized antioxidant that can help stabilize other ingredients in a formula, like vitamin C, from breaking down.
Citric Acid References
Citric Acid: An Alpha and Beta Hydroxyacid for Antiaging, Journal of the American Academy of Dermatology, 2004
Topical AHA in Dermatology: Formulations, Mechanisms of Action, Efficacy, and Future Perspectives, Cosmetics, 2023
Our team reviews ingredient research and uses up-to-date evidence to rate ingredients based on the categories below.
Best
Ingredients with the most rigorous and convincing evidence. These are the standouts backed by consistent findings across independent, peer reviewed clinical research.. When we call an ingredient Best, it has earned that distinction through genuine, reproducible proof that it improves skin.
Good
Reliable, well tolerated ingredients that do their job without complaint. They may not carry the headline benefits of a Best rated active, but they hydrate, stabilize a formula, or support the ingredients around them in ways that make a real difference in how a product performs and feels.
Average
Ingredients that are perfectly safe and serve a clear function, typically as an emollient, thickener, or filler, but do not offer any meaningful skin benefit beyond that basic job. Not a red flag, just not a reason to choose one product over another.
Bad/Worst
Ingredients with documented potential to irritate skin, disrupt the barrier, or trigger sensitization in some users, often synthetic fragrance, drying forms of alcohol, or certain essential oils. Not automatically a dealbreaker for every skin type, but worth knowing about before you commit to a product.
