Citric Acid
SIH-trik AS-id
What Is Citric Acid?
Citric Acid is a naturally occurring alpha hydroxy acid (AHA) found abundantly in citrus fruits. In hair care, it primarily functions as a pH adjuster to keep formulations at the optimal acidic pH for hair health (4.5-5.5). It also acts as a chelating agent that removes hard water mineral buildup and helps seal the hair cuticle for improved shine.
Source: Citrus fruits or produced via microbial fermentation (Aspergillus niger)
Origin: Natural
Also known as: Vitamin C Acid, Sour Salt, Anhydrous Citric Acid, E330
What Does Citric Acid Do to Your Hair?
Citric Acid lowers the pH of hair care formulations to the mildly acidic range optimal for hair cuticle closure. A closed cuticle reflects more light (shine), retains moisture better, and resists damage. It also chelates (binds to) calcium and magnesium ions from hard water that cause buildup and dullness. At higher concentrations, it provides mild exfoliation.
Best For
All hair types, hard water areas, dull hair, color-treated hair (pH maintenance), high-porosity hair
Not Recommended For
Sensitive scalp at high concentrations, open wounds
Concentration Matters
0.1-2%
Hair Type Compatibility
Method Compatibility
Safety & Regulation
Very safe at cosmetic concentrations. Can cause mild irritation at high concentrations or prolonged contact on sensitive skin. The cosmetic concentrations used in hair care (typically under 2%) are well within safety margins. No systemic toxicity from topical use.
FDA Status: Generally Recognized As Safe
FDA classifies as GRAS for food use. Permitted in cosmetics without restrictions. Used in FDA-approved pharmaceutical preparations.
EWG Score: 1/10
HairAide Verdict
Citric Acid is a small but mighty ingredient that does critical behind-the-scenes work in hair care. It keeps products at the right pH for hair health and removes hard water buildup. If you live in a hard water area, a citric acid rinse can dramatically improve shine and softness. HairAide considers it an essential functional ingredient.
Products That Contain Citric Acid
Shampoos, conditioners, hair rinses, chelating treatments, color-protecting products
Alternatives to Citric Acid
If you want to avoid Citric Acid, look for products with these ingredients instead:
Acetic Acid (apple cider vinegar), Lactic Acid, Phytic Acid, EDTA (for chelating)
Frequently Asked Questions
Yes, Citric Acid has a safety rating of 9/10 and is generally considered safe for use in hair products. Very safe at cosmetic concentrations. Can cause mild irritation at high concentrations or prolonged contact on sensitive skin. The cosmetic concentrations used in hair care (typically under 2%) are well within safety margins. No systemic toxicity from topical use.
Citric Acid is CG-method approved and is generally considered safe for curly hair.
Yes, Citric Acid is approved for the Curly Girl method.
Some alternatives to Citric Acid include: Acetic Acid (apple cider vinegar), Lactic Acid, Phytic Acid, EDTA (for chelating)
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