Methylparaben
Also known as Methyl parahydroxybenzoate, Methyl p-hydroxybenzoate, Methyl 4-hydroxybenzoate, Nipagin M, Methylparaben
“CIR Expert Panel says: safe as used in cosmetics.”
Methylparaben (methyl p-hydroxybenzoate; CAS 99-76-3; C8H8O3) is a short-chain paraben ester and one of the most extensively studied cosmetic preservatives. The 2008 CIR amended paraben re-review (Int J Toxicol 27 Suppl 4:1-82, PMID 19101832) assessed the seven short-chain parabens together and concluded methylparaben 'safe as used' — an unconditional 'S' finding in the CIR Quick Reference Table with no detail-column conditions. The 2023 SCCS Opinion on Methylparaben (SCCS/1652/23, adopted 14 December 2023, corrigendum 28 February 2024) is the first SCCS opinion ingredient-specific to methylparaben (prior SCCS opinions on parabens — SCCS/1348/10, SCCS/1446/11, SCCS/1514/13 — were focused on propyl- and butylparaben, not methylparaben). SCCS/1652/23 explicitly considered concerns related to potential endocrine disrupting properties and concluded methylparaben safe as a preservative at up to 0.4% as acid when used on its own, and up to 0.4% in mixtures of esters whose total does not exceed 0.8% (as acid) — i.e., the long-standing Annex V entry 12 limits remain unchanged after the 2023 endocrine-focused re-review. The Darbre 2004 paper (PMID 14745841) detected parabens in breast tumour tissue; this finding generated substantial consumer concern but was evaluated by regulatory bodies and judged insufficient to alter the safety conclusion for methylparaben, a position reaffirmed in SCCS/1652/23. Patch-test contact allergy to methylparaben is documented (Sánchez-Pérez 2006, PMID 16487285) but uncommon — parabens are characterized as among the least sensitizing cosmetic preservatives (Hafeez & Maibach 2013, PMID 24305662).
Among the most extensively studied cosmetic preservatives globally; long safety record across both CIR (2008) and SCCS (2023) frameworks
Broad-spectrum antimicrobial activity particularly effective against molds and yeasts; water-soluble and compatible with a wide pH range
CIR unconditional 'S' finding (2008) and SCCS approved at 0.4% (as acid) without pediatric restriction in the most recent ingredient-specific re-review (SCCS/1652/23, 2023) — among the most favorably assessed preservatives in both regulatory frameworks even after explicit endocrine re-evaluation
Consumer-transparent: appears clearly on ingredient labels as 'methylparaben', enabling informed avoidance for consumers who choose paraben-free formulations
Endocrine disruption concern: parabens have weak estrogenic activity measurable in vitro; SCCS/1652/23 (2023) explicitly evaluated this concern for methylparaben specifically and concluded the ingredient remains safe at 0.4% as acid — the Annex V entry 12 limits were not tightened after the endocrine review
Darbre 2004 reported paraben detection in human breast tumour tissue with methylparaben as the predominant species (≈62% of total paraben recovered); detection in tissue does not establish causation, and regulatory bodies (CIR 2008, SCCS 2023) evaluated the work and did not find it sufficient to restrict methylparaben
Contact allergy: documented case reports of allergic and systemic contact dermatitis to methylparaben; patch-test prevalence is low and parabens are characterized as among the least sensitizing cosmetic preservatives
CIR Quick Reference Table (12/2017, revised 07/2018) — Methylparaben row: Finding=S, Citation=IJT 27(S4):1-82, 2008; JACT 3(5):147-209, 1…
“Methylparaben | S | | IJT 27(S4): 1-82, 2008 JACT 3(5):147-209, 1984 (original report)”— QRT-122017revised072018.pdf, p. 75
SCCS/1652/23 — Final Opinion on Methylparaben (CAS 99-76-3, EC 202-785-7), adopted 14 December 2023 (corrigendum 28 February 2024)
“the SCCS is of the opinion that the use of Methylparaben as a preservative in cosmetic products at concentrations of up to 0.4% (expressed as acid) is safe. It is also safe when used up to 0.4% in a mixture of esters for which the total concentration of all esters does not exceed 0.8% (as acid), as indicated in entry 12 of Annex V to the Cosmetics Regulation.”— SCCS/1652/23, p. 3 (Abstract, conclusion to Question 1)