2,4-Di-tert-butylphenol-d21 (2,4-DTBP-d21) is the deuterium labeled 2,4-Di-tert-butylphenol (HY-W014589). 2,4-Di-tert-butylphenol (2,4-DTBP) is an orally active RXRalpha activator and a human estrogen receptor ligand with anti-inflammatory and antioxidant activities, which can induce apoptosis in tumor cells. 2,4-Di-tert-butylphenol can activate the RXRalpha subtype in LXRalpha/RXRalpha, PPARgamma/RXRalpha, and hormone receptor beta/RXRalpha. 2,4-Di-tert-butylphenol also has antiviral and antifungal activities and has the potential to inhibit Abeta-induced neurotoxicity. 2,4-Di-tert-butylphenol can be used as an intermediate in the preparation of antioxidants and UV stabilizers, and is also used in the manufacture of drugs and fragrances[1][2][3].