SLCO1B1*5 is assigned no function based on definitive evidence in heterozygous and SLCO1B1*5/*15 compound heterozygote individuals. The plasma levels of highly sensitive OATP1B1 endogenous substrates GCDCA-3G and GDCA-3G are significantly higher in SLCO1B1*1/*5 and SLCO1B1*5/*15 heterozygotes than in individuals with the SLCO1B1*1/*1 homozygotes (32961594). In vitro studies have demonstrated significantly reduced uptake of estrone sulfate and estradiol 17beta-d-glucuronide (11477075), and several other substrates compared to SLCO1B1*1 (21245207).Therefore, consensus among experts was no function on definitive evidence.