20 mg quantity of unlabeled promegestone (R5020). This product is non-radioactive. Promegestone is a steroid that acts as an agonist of the progesterone receptor.

References for NLP004:

1. Ortega-Moreno, J. Receptor concentrations for estradiol and progesterone in surgically induced endometriosis in the rat. European Journal of Obstetrics and Gynecology and Reproductive Biology 54, 123–126 (1994).
2. Ree, A. H. et al. Autologous Down-Regulation of Messenger Ribonucleic Acid and Protein Levels for Estrogen Receptors in MCF-7 Cells: An Inverse Correlation to Progesterone Receptor Levels. Endocrinology 124, 2577–2583 (1989).
3. Ali, H. et al. Synthesis of the 7α-cyano-(17α,20E/Z)-[125I]iodovinyl-19-nortestosterones: potential radioligands for androgen and progesterone receptors. Steroids 68, 1163–1171 (2003).
4. Lesser, M. L. et al. Estrogen and progesterone receptors in breast carcinoma: Correlations with epidemiology and pathology. Cancer 48, 299–309 (1981).