Citric acid
Sets how acidic a product is.
How common
5,585 of 14,784 products with a full ingredient list in Open Beauty Facts; No. 4 of all the names found on their labels.
What it is
An acid that is also a food additive: in the US it is “generally recognized as safe” in food.
SourceHide
because citric acid, calcium citrate, ferric citrate, manganese citrate, potassium citrate, sodium citrate, diammonium citrate, isopropyl citrate, stearyl citrate, and triethyl citrate are generally recognized as safe direct food additives
[1] US Cosmetic Ingredient Review expert panel · 2014 · open source
Why it is in products
Mainly to set the product’s acidity (its pH), and to bind traces of metals (a chelating agent).
SourceHide
Citric acid is reported to function as a pH adjuster, chelating agent, or fragrance ingredient.
[1] US Cosmetic Ingredient Review expert panel · 2014 · open source
What it does
In shampoo, a lower pH (5.5 or below) may mean less frizz: alkaline products add negative charge to the hair’s surface, so hairs rub against each other more. In a test of 123 shampoos, 62% had a pH above 5.5.
Some evidencehair2 sourcesHide
Alkaline pH may increase the negative electrical charge of the hair fiber surface and, therefore, increase friction between the fibers. This may lead to cuticle damage and fiber breakage.
[2] Study · 2014 · open source61.78% presented a pH > 5.5
[2] Study · 2014 · open sourceHealthy skin’s surface is acidic, on average below pH 5. In one study, skin below pH 5 was in better condition than skin above it.
Some evidenceskin2 sourcesHide
it is estimated that the 'natural' skin surface pH is on average 4.7, i.e. below 5.
[3] Study · 2006 · open sourceIt is demonstrated that skin with pH values below 5.0 is in a better condition than skin with pH values above 5.0
[3] Study · 2006 · open source
Downsides and safety
The US expert panel concluded it is safe as used in cosmetics.
Well establishedSourceHide
concluding that these ingredients are safe in the present practices of use and concentration
[1] US Cosmetic Ingredient Review expert panel · 2014 · open source
Where it works
It works in the product, setting its pH; in a shampoo, that pH then acts on the hair’s surface charge.
Some evidenceSourceHide
Alkaline pH may increase the negative electrical charge of the hair fiber surface[2] Study · 2014 · open source
Rules
European Union
No EU limit: it is not on the regulation’s lists of banned or restricted substances, preservatives or UV filters.
How we checkedHide
We searched Annexes II to VI of the EU regulation (consolidated text of 18 May 2026): no entry (its nickel salts and the silver citrate mix are separate entries).open the list
United States
Not on the FDA’s list of prohibited or restricted cosmetic ingredients. In the US, cosmetics and their ingredients (other than colour additives) don’t need FDA approval before sale.
SourceHide
Under U.S. law, cosmetic products and ingredients, other than color additives, do not need FDA approval before they go on the market
[4] US Food and Drug Administration · open sourceWe searched the FDA’s list of prohibited and restricted cosmetic ingredients: no entry.open the list
Sources
- Safety Assessment of Citric Acid, Inorganic Citrate Salts, and Alkyl Citrate Esters as Used in Cosmetics International journal of toxicology, 2014US Cosmetic Ingredient Review expert panel
- The Shampoo pH can Affect the Hair: Myth or Reality? International Journal of Trichology, 2014Study
- Natural skin surface pH is on average below 5, which is beneficial for its resident flora Lambers H et al., International journal of cosmetic science, 2006StudyAuthors include staff of Sara Lee Household and Body Care
- Prohibited & Restricted Ingredients in Cosmetics | FDA US Food and Drug Administration
Checked against these sources on 4 November 2026. Spot a mistake? Tell us.