Preload all chemical data:

    ChemicalData[All, "Preload"];
    RebuildPacletData[]; (* the latter should not really be necessary *)

Get all names:

    cd = ChemicalData[];

Get their molecular formulae:

    l = ChemicalData[#, "MolecularFormulaString"] & /@ cd;

By counting the Cs, Os and Hs in the tattooed diagram we know we have to find $\rm{C_{19}H_{28}O_{2}}$. Looking for all molecules that have that molecular formula:

    p = Position[l, "C19H28O2"];

    Column[Labeled[ChemicalData[#, "StructureDiagram"], #] & /@ Extract[cd, p]]

![Mathematica graphics](http://i.stack.imgur.com/xK0u0.png)

Looks like it is Testosterone.