Some info on Tren..
As a general rule, all androgens will produce secondary effects on lipolysis by binding with androgen receptors located in adipose tissue. Essentially, the stronger the androgen, the higher affinity it will have with binding to these receptors. This bind will stimulate the mobilization of fatty acids, and ultimately the oxidation of them assuming that a caloric deficit is adhered to. Trenbolone by itself, and alongside estrogen, has been shown to reduce subcutaneous fat, intermuscular fat, and decrease muscle marbling (another measurement of intramuscular fat content).
Although, the binding of trenbolone to androgen receptors in adipose tissue is fairly straight forward, the precise mechanism(s) through which it reduces body fat remain to be determined. Many speculate it may involve a direct stimulation of lipolysis, as demonstrated by an increased expression of enzymes involved in lipolysis in the liver, including enoyl-coA-hydratase (EnoylCoA) and acyl-coA-dehydrogenase.
In various rat studies, there has been an inability for males to gain body weight following trenbolone administration. The speculation here is that this may result from a reduction in total body fat mass or perhaps intramuscular fat content, similar to what has been observed in other species.
K. Blouin, A. Veilleux, V. Luu-The, A. Tchernof - Androgen metabolism in adipose tissue: recent advances Mol Cell Endocrinol, 301 (2009), pp. 97?103
R.C. Herschler, A.W. Olmsted, A.J. Edwards, R.L. Hale, T. Montgomery, R.L. Preston, et al. - Production responses to various doses and ratios of estradiol benzoate and trenbolone acetate implants in steers and heifers J Anim Sci, 73 (1995), pp. 2873?2881
B.A. Reiling, D.D. Johnson - Effects of implant regimens (trenbolone acetate-estradiol administered alone or in combination with zeranol) and vitamin D3 on fresh beef color and quality J Anim Sci, 81 (2003), pp. 135?142
J.A. Samber, J.D. Tatum, M.I. Wray, W.T. Nichols, J.B. Morgan, G.C. Smith - Implant program effects on performance and carcass quality of steer calves finished for 212 days J Anim Sci, 74 (1996), pp. 1470?1476
M. Reiter, V.M. Walf, A. Christians, M.W. Pfaffl, H.H. Meyer -Modification of mRNA expression after treatment with anabolic agents and the usefulness for gene expression-biomarkers Anal Chim Acta, 586 (2007), pp. 73?81
Some other neat things that have been seen during rodent studies is trenbolone's somewhat unique abilities to decrease retroperitoneal (behind abdominal cavity), perirenal (kidney), and other fat depots. I have been trying to get my hands on these studies however they are unpublished, as far as I know...
Time and time again, the lipolytic effects of trenbolone (enanthate) have been superior to testosterone (enanthate) in comparable exogenous doses. Although I would urge folks not to think of trenbolone as a "fat burner", it can definitely assist one's goals when combined with a proper diet and lifestyle.