Diisostearyl Malate
Also known as diisostearyl malate, di-isostearyl malate, bis(isostearyl) malate
“CIR Expert Panel says: safe as used in cosmetics.”
Diisostearyl malate is a diester of isostearyl alcohol and malic acid used primarily as an emollient and gloss agent in lip products. The CIR Expert Panel (2015) assessed six dialkyl malates and found them safe at current practices of use and concentration. Two case reports document contact sensitization from diisostearyl malate in lipstick, with the Hayakawa 1987 study implicating isostearyl alcohol impurities in the malate as the true sensitizer rather than the ester itself.
Non-irritating, non-sensitizing emollient with excellent gloss and lip-feel properties
Provides sheen, spreadability, and skin-conditioning in lip products and color cosmetics
High lipophilicity (logP ~17) limits dermal penetration; metabolic hydrolysis yields malic acid and isostearyl alcohol, both of established safety
- · Primarily used in lip products at high concentrations; impurity profile of commercial-grade material may vary by supplier
Case reports of allergic contact cheilitis attributed to diisostearyl malate in lipstick; Hayakawa et al. (1987, PMID 3595121) found impurities (branched C18 aliphatic compounds with primary alcohol groups) in the diisostearyl malate material were the likely sensitizing agents rather than the pure ester
CIR Quick Reference Table (12/2017, revised 07/2018) — DIISOSTEARYL MALATE row: Finding=S, Citation=IJT 34(S1): 5-17, 2015
“Diisostearyl Malate | S | | IJT 34(S1): 5-17, 2015”— QRT-122017revised072018.pdf, p. 44