Polysorbate 20
Also known as Polyoxyethylene (20) sorbitan monolaurate, Tween 20, PEG(20) sorbitan monolaurate, Sorbitan monolaurate, poly(oxy-1,2-ethanediyl) derivatives
“CIR Expert Panel says: safe as used in cosmetics.”
Polysorbate 20 (polyoxyethylene (20) sorbitan monolaurate; Tween 20; CAS 9005-64-5) is a nonionic surfactant formed by ethoxylation of sorbitan monolaurate with approximately 20 ethylene oxide units per sorbitan core. In cosmetic formulations it functions as a hydrophilic nonionic emulsifier, solubilizer (particularly for essential oils and fragrance compounds in aqueous products), and dispersing agent. It is the most commonly used member of the polysorbate series because its HLB value (approximately 16.7) is well-suited to solubilizing lipophilic actives into water-based formulations. The Cosmetic Ingredient Review Expert Panel originally assessed Polysorbate 20 and eight other polysorbates (21, 40, 60, 61, 65, 80, 81, 85) in 1984 (J Am Coll Toxicol 3(5):1-82) and concluded they are safe as cosmetic ingredients. The Panel issued an amended final report in June 2015 that reaffirmed the 1984 conclusion with updated use data and additional toxicology. The QRT row carries the Detail 'safe as used when formulated to be non-irritating', reflecting the Panel's qualification that formulators must ensure the finished product is non-irritating — a standard qualification for surfactants that applies equally to other common nonionic emulsifiers. Polysorbates are hydrolyzed by pancreatic and blood lipases upon oral or systemic exposure: the fatty acid moiety (lauric acid for Polysorbate 20) is released and metabolized normally, while the polyoxyethylene sorbitan backbone is poorly absorbed and excreted unchanged. Acute and long-term oral toxicity studies show a low order of toxicity, and dermal studies show Polysorbate 20 is non-irritating and non-sensitizing at typical cosmetic use concentrations (0.5-5%).
Primary hydrophilic nonionic emulsifier and solubilizer in cosmetic formulations — HLB approximately 16.7 makes it ideal for solubilizing essential oils, fragrance compounds, and lipophilic actives into water-based toners, essences, and serums
Non-ionic compatibility: does not interact with most anionic or cationic ingredients, allowing broad formulation flexibility
CIR Expert Panel concluded safe as used in cosmetics:1-82, 1984; reaffirmed in the June 2015 amended polysorbates assessment) — same assessment clears Polysorbates 21, 40, 60, 61, 65, 80, 81, and 85
- · Rare contact allergy reports exist in the patch-test literature at low prevalence
1,4-Dioxane trace impurity (documented byproduct in the byproducts section) — a recognized manufacturing byproduct of the ethoxylation process; industry standard is vacuum stripping to reduce residual levels below ~10 ppm, and the CIR 2015 assessment considered this when concluding safety
As a surfactant, Polysorbate 20 can enhance the skin penetration of other ingredients in the formulation — typically desired (it helps water-soluble actives reach the stratum corneum) but formulators should consider the consequences when paired with actives that should NOT penetrate (e.g., sunscreen filters intended to stay on the surface)
CIR Quick Reference Table (12/2017, revised 07/2018) - Polysorbate 20 row: Finding 'SQ' (Safe Qualified) with Detail 'safe as used when f…
“Polysorbate 20 | SQ | safe as used when formulated to be non-irritating | JACT 3(5):1-82, 1984; Final report 06/2015 available from CIR”— QRT-122017revised072018.pdf, p. 108