The function of RDH16 (retinol dehydrogenase 16, ENSG00000139547) is as follows. Oxidoreductase with a preference for NAD. Oxidizes all-trans- retinol, 9-cis-retinol, 11-cis-retinol and 13-cis-retinol to the corresponding aldehydes (PubMed:10329026, PubMed:12534290, PubMed:9677409). Has higher activity towards CRBP-bound retinol than with free retinol (PubMed:12534290). Also oxidizes 3-alpha- hydroxysteroids. Oxidizes androstanediol and androsterone to dihydrotestosterone and androstanedione. Can also catalyze the reverse reaction (PubMed:10329026, PubMed:29541409, PubMed:9677409). {ECO:0000269|PubMed:10329026, ECO:0000269|PubMed:12534290, ECO:0000269|PubMed:29541409, ECO:0000269|PubMed:9677409}.