α-Hydroxytamoxifen is a metabolite of tamoxifen. It reacts with DNA and causes the formation of DNA adducts.

SNIPER(ER)-87 is a chemical compound composed of a derivative of the inhibitor of apoptosis protein (IAP) ligand LCL161 conjugated to the estrogen receptor α (ERα) ligand 4-hydroxytamoxifen using a PEG linker. It effectively degrades the ERα protein with an IC50 value of 0.097 μM. Within cells, SNIPER(ER)-87 selectively recruits XIAP to ERα, and XIAP functions as the primary E3 ubiquitin ligase responsible for the degradation of ERα induced by SNIPER(ER)-87[1][2].