testosterone palmitate testosterone palmitate testosterone palmitate, also known as testosterone hexadecanoate, testosterone 17β-palmitate, and androst-4-en-17β-ol-3-one 17β-palmitate, is an anabolic-androgenic steroid (aas) and an androgen ester – specifically, the c17β palmitate (hexadecanoate) ester of testosterone – which was never marketed. it is a prodrug of testosterone and, when administered via intramuscular injection, is associated with a long-lasting depot effect and extended duration of action. testosterone palmitateclinical dataother namestestosterone hexadecanoate; testosterone 17β-palmitate; androst-4-en-17β-ol-3-one 17β-palmitateroutes ofadministrationoral, intramuscular injectionidentifiers iupac name phenanthren-17-yl] hexadecanoate cas number991-20-8pubchem cid164765chemspider144440uniiuv7u6aq9kpcomptox dashboard (epa)dtxsid00912871 chemical and physical dataformulac35h58o3molar mass526.846 g·mol−13d model (jsmol)interactive image smiles cccccccccccccccc(=o)o1cc21(cc32ccc4=cc(=o)cc34c)c inchi inchi=1s/c35h58o3/c1-4-5-6-7-8-9-10-11-12-13-14-15-16-17-33(37)38-32-21-20-30-29-19-18-27-26-28(36)22-24-34(27,2)31(29)23-25-35(30,32)3/h26,29-32h,4-25h2,1-3h3/t29-,30-,31-,32-,34-,35-/m0/s1key:okfbxyqpcpwwrp-shdaaxgtsa-n testosterone palmitate is a longer-chain ester of testosterone compared to testosterone undecanoate. relative to testosterone undecanoate, testosterone palmitate shows higher oral bioavailability. however, no free testosterone was observed after administration of testosterone palmitate, suggesting that it is not hydrolyzed as efficiently as testosterone undecanoate. on the other hand, another study found that testosterone palmitate was hydrolyzed in humans.