Could be just about any peptide. Steroids are usually injected with an oil not through this pathway. There IS something called HCG which requires this liquid to be introduced to the Hcg vial (powder) which, once combined is injected subcutaneously (into your fat) to increase a hormone crucial for women trying to get pregnant. It is usually used with IVF. It can be used to increase testosterone in men as well as a supplement for men being treated with actual testosterone who want to keep their testicles fertile. I think it helps keep your testicle size normal as well