Ethinyl estradiol is a synthetic derivative of the natural estrogen estradiol. It is one of two estrogens currently used in oral contraceptive pills. The other, mestranol, is converted to ethinyl estradiol before it is biologically active. Ethinyl estradiol and norethindrone are used together as an oral contraceptive agent. Estrogens diffuse into their target cells and interact with a protein receptor. Target cells include the female reproductive tract, the mammary gland, the hypothalamus, and the pituitary. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. This cascade is initiated by initially binding to the estrogen receptors. The combination of an estrogen with a progestin suppresses the hypothalamic-pituitary system, decreasing the secretion of gonadotropin-releasing hormone (GnRH). Used for treatment of moderate to severe vasomotor symptoms associated with the menopause, female hypogonadism, prostatic carcinoma-palliative therapy of advanced disease, breast cancer, as an oral contraceptive, and as emergency contraceptive.

Estradiol benzoate is the synthetic benzoate ester of estradiol, a steroid sex hormone vital to the maintenance of fertility and secondary sexual characteristics in females. As the primary, most potent estrogen hormone produced by the ovaries, estradiol binds to and activates specific nuclear receptors. This agent exhibits mild anabolic and metabolic properties, and increases blood coagulability. Although estradiol benzoate is not approved by the FDA for use in humans in the United States, it is approved for veterinary use as a subdermal implant both alone (CELERIN®) and in combination with the anabolic steroid trenbolone acetate (SYNOVEX® Plus).

Osaterone acetate (previously known as TZP-4238), a synthetic steroidal anti-androgen agent. Osaterone acetate is used in veterinary in Europe in the treatment of benign prostatic hyperplasia (BPH) in male dogs. Osaterone acetate inhibits the effects of an excess of male hormone (testosterone) through various mechanisms. It competitively prevents the binding of androgens to their prostatic receptors and blocks the transport of testosterone into the prostate. Osaterone acetate was also investigated in Japan in the treatment of prostate cancer and BPH and, in addition, was studied in postmenopausal osteoporosis in humans. However, these studies were discontinued.

Phorbol 12-myristate 13-acetate (PMA) also commonly known as 12-O-Tetradecanoylphorbol-13-acetate (TPA) is a phorbol ester that is commonly used to activate phospholipid-dependent protein kinase (protein kinase C). PMA/ TPA possesses potential antineoplastic effects and was studied in phase II clinical trials together with dexamethasone in patients with relapsed or refractory acute myeloid leukemia. In addition, PMA/ TPA participated in phase I trial for treating patients with hematologic cancer or bone marrow disorder that has not responded to previous treatment. Nevertheless, both clinical trials were terminated. Besides, PMA/ TPA was studied in patients with solid tumors, which had depressed white blood cell and neutrophil counts because of prior treatment with cytotoxic cancer chemotherapeutic drugs. It was shown, that the drug increased the low white blood cell and neutrophil counts toward the normal range.

Phenylacetate is the ester of a phenol and acetic acid. It is a metabolite of anticancer drug phenylbutyrate (PB), natural neurotransmitter phenylethylamine. Naturally, it is an odorant found in strawberries, passion fruit, and black tea. Phenylacetate level in urine was used as a marker for the diagnosis of some forms of unipolar major depressive disorders. Phenylacetate is used as a tool substrate to study esterase activity in the blood of patients in clinical studies of the effect of nutritional supplements on paraoxonase-1 levels.