Benzoic Acid
Also known as Benzoic acid, Phenylformic acid, Benzenecarboxylic acid, Dracylic acid
“EU CosIng says: restricted.”
Benzoic acid (CAS 65-85-0; C7H6O2) is a widely used cosmetic preservative with extensive safety assessment history. The CIR Expert Panel originally assessed Benzyl Alcohol, Benzoic Acid, and Sodium Benzoate in 2001 (Nair B, IJT 20(Suppl 3):23-50, PMID 11766131), concluding safe up to 5%. In 2017, an amended re-review expanded the assessment to include additional benzoic acid salts and benzyl benzoate (Johnson et al., IJT 36(Suppl 3):5S-30S, PMID 29243541), with the QRT recording a plain 'S' (Safe) without concentration restriction — meaning the updated CIR assessment does not carry a numeric cap. EU Cosmetics Regulation Annex V permits benzoic acid as a preservative with product-type-dependent concentration limits: 2.5% in rinse-off (except oral), 1.7% in oral products, and 0.5% in leave-on products. The ingredient can cause nonimmunologic contact urticaria and enhanced irritant reactions on compromised skin barrier (Lahti et al., Contact Dermatitis 1995, PMID 8565459).
Broad-spectrum antimicrobial at low pH — effective against bacteria, yeasts, and molds; one of the longest-used preservatives in both food and cosmetics
CIR Expert Panel concluded safe as used in cosmetics (Johnson et al. IJT 2017, PMID 29243541; original 2001 assessment PMID 11766131) — updated 2017 assessment carries no concentration restriction
FDA GRAS (Generally Recognized As Safe) as a direct food additive; extensive history of safe use in food and food-adjacent cosmetic formulations
WHO acceptable daily intake of 5 mg/kg body weight established for the benzoic acid / sodium benzoate group — supports long-term safety at regulatory cosmetic concentrations
EU Annex V listed — explicitly reviewed and permitted by EU regulatory authorities as an allowed preservative with defined product-type caps
- · Nonimmunologic contact urticaria reported at higher concentrations — a direct irritant effect (not immune-mediated) documented in human studies
- · Enhanced irritant reactions on skin with compromised barrier function (e.g., washed or damaged skin) — Lahti et al. 1995 showed reactions stronger on repeatedly washed skin
- · Effective antimicrobial activity is pH-dependent (most active at pH 2.5–4.5 as undissociated acid); at higher pH the benzoate ion predominates and activity drops significantly
- · EU Annex V caps differ substantially by product type (0.5% leave-on vs. 2.5% rinse-off) — formulators must respect the applicable limit for their product category
In combination with ascorbic acid under UV exposure, benzoate can undergo decarboxylation to form trace benzene — primarily a concern in food/beverage context but worth noting for vitamin C cosmetic formulations
- · 2.5% Rinse-off products, except oral products (EU Annex V Entry 1(a))
- · 1.7% Oral products (toothpaste, mouthwash) (EU Annex V Entry 1(b))
- · 0.5% Leave-on products (EU Annex V Entry 1(c))
CIR Quick Reference Table (12/2017, revised 07/2018) — Benzoic Acid row: Finding=S, Citation=IJT 36(Suppl. 3):5-30, 2017; original IJT 20…
“Benzoic Acid | S | | IJT 36(Suppl. 3):5-30, 2017; original IJT 20(S3):23-50, 2001”— QRT-122017revised072018.pdf, p. 11
Regulation (EC) No 1223/2009 Annex V — Entry 1: Benzoic acid and its sodium salt; product-type-conditional concentration limits (legislat…
“Reference number 1: Benzoic acid and its sodium salt — (a) Rinse-off products, except oral products: 2,5 % (acid)”— Regulation (EC) No 1223/2009, Annex V, Entry 1(a)