mequinol mequinol mequinol, mehq or 4-methoxyphenol, is a phenol used in dermatology and organic chemistry. mequinolclinical dataother names4-hydroxyanisole; para-guaiacolahfs/drugs.cominternational drug namesmedlineplusa682437routes ofadministrationtopicalatc coded11ax06 (who) legal statuslegal status ca: unscheduled us: ℞-only and unscheduled in general: unscheduled identifiers iupac name 4-methoxyphenol cas number150-76-5 ypubchem cid9015iuphar/bps6827chemspider8665 yunii6ht8u7k3amkeggd04926 ychemblchembl544 ycomptox dashboard (epa)dtxsid4020828 echa infocard100.005.246 chemical and physical dataformulac7h8o2molar mass124.139 g·mol−1density1.55 g/cm3melting point52.5 °c (126.5 °f)boiling point243 °c (469 °f) inchi inchi=1s/c7h8o2/c1-9-7-4-2-6(8)3-5-7/h2-5,8h,1h3 ykey:nwvvvbrkawdgab-uhfffaoysa-n y (verify) uses dermatology mequinol is a common active ingredient in topical drugs used for skin depigmentation. as a topical drug mequinol is often mixed with tretinoin, a topical retinoid. a common formulation for this drug is an ethanolic solution of 2% mequinol and 0.01% tretinoin by mass. dermatologists commonly prescribe the drug to treat liver spots. lower dosages of mequinol have been used in conjunction with a q-switched laser to depigment skin in patients with disseminated idiopathic vitiligo. organic chemistry in organic chemistry 4-methoxyphenol is used as a polymerisation inhibitor (e.g. acrylates or styrene monomers). preparation 4-methoxyphenol is produced from p-benzoquinone and methanol via a free radical reaction. safety people can be exposed to 4-methoxyphenol in the workplace by breathing it in, skin absorption, swallowing it, skin contact, and eye contact. the national institute for occupational safety and health (niosh) has set a recommended exposure limit (rel) of 5 mg/m3 over an 8-hour workday.