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Medically reviewed by Last updated on Feb 22, 2023.

Excipient (pharmacologically inactive substance)

What is it?

Isobutylparaben, with the chemical formula of C11H14O3 is an antimicrobial preservative used in many cosmetics, as a food flavoring agent and as a suspending agent for medications. Isobutylparaben used in industry is synthetically created, but natural parabens also exist in nature.

All parabens have similar structure to estrogen. Studies conducted in the early 2000s located traces of parabens in breast tumors, but evidence has not linked parabens with breast cancer. The Cosmetic Ingredient Review (CIR) reviewed the safety of methylparaben, propylparaben, and butylparaben in 1984 and concluded they were safe for use in cosmetic products at levels up to 25%. Typically parabens are used at levels ranging from 0.01 to 0.3%.[1]


  1. US Food and Drug Administration. Cosmetics. Parabens. Accessed August 19, 2012.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.