Trenbolone

Trenbolone acetate is a synthetic steroid that is extensively used in the United States as a growth promoter in beef cattle. The acetate is administered to livestock via slow-release implants; some is converted by the animal to 17-β-trenbolone, a relatively potent androgen receptor agonist in mammalian systems. Recent studies indicate that excreted 17-β-trenbolone is comparatively stable in animal waste and in so doing has become a classic endocrine disruptor being able to modify the sex of various fish such as guppies.

Ankley, G. T., Jensen, K. M., Makynen, E. A., Kahl, M. D., Korte, J. J., Hornung, M. W., Henry, T. R., Denny, J. S., Leino, R. L., Wilson, V. S., Cardon, M. C., Hartig, P. C. and Gray, L. E. (2003), Effects of the androgenic growth promoter 17-β-trenbolone on fecundity and reproductive endocrinology of the fathead minnow. Environmental Toxicology and Chemistry, 22 pp. 1350–1360. doi: 10.1002/etc.5620220623