Oct 6, 2010 Halotestin (Fluoxymesteron) is legendary among powerlifters and strength athletes. The mere word conjures up images of little mint colored pills that turn Dr. Jeckyl instantly into Mr.Hyde. Since I´m generally Mr.Hyde 24/7 this isn´t of much concern to me.. but lets see what else Halotestin can do for us. If you´re anything like me, the first thing you´ll notice is Halotestin´s absurd Anabolic and Androgenic rating. This stuff is 19x as anabolic as testosterone and 8.5x as androgenic! Whoa! I have to admit, those numbers are a bit deceiving, and through personal experience, I can say that Halotestin will not put anywhere near as much muscle on you as testosterone. Let´s take a closer look at Halo and see what kind of realistic effects we can expect from it, and what kind of side effects we´ll be dealing with. Firstly, I have to admit that I love this stuff, and generally its use in athletics and powerlifting is far more pronounced than it´s use in bodybuilding, where it is basically a one-trick-wonder used in the final weeks before a contest to harden up an already lean physique and give the user some added aggression during the final calorie depleted workouts before a contest. Halo has no estrogenic activity, and thus will not cause any kind of water retention or most of the bad effects associated with estrogen. It is however hepatoxic (liver toxic) (13) and I recommend keeping doses at or around 40mgs/day for a maximum of 4-6 weeks. If you are using it for it´s pronounced effect on aggression, you can simply use 10mgs prior to a workout, I personally prefer 10mgs upon rising and 10mgs prior to a workout, during the most intense weeks of a bulking or cutting cycle. This does (as you will see later) can be used with minimum HPTA inhibition. Effects of Halotestin Halotestin also has a volumizing effect on the physique, and for those with low a body fat percentage, this will cause an immediately more contest ready appearance. This is due, at least in part, to Halo´s ability to increase mean hematocrit with and hemoglobin level as well as red cell mass (4)(5)(6). Halotestin also appears to act through cells already committed to respond to erythropoietin (11), which is good news for athletes, of course. As you can see, Halo has quite a profound effect on red blood cell production, and this action is clearly one of the most obvious mechanisms by which it is thought to exert its effects with regards to increasing strength and energy levels. It also points to the possibility of using it for athletics and sports where a high VO2 max is needed, such as Rugby, Mixed Martial Arts, etc.. It also exerts its effects on strength and fat loss by both regulation of fatty acid oxidation in the liver and fast-twitch muscle mitochondria (2). Oddly, for a drug which exerts such a nice anabolic effect, and promotes such good strength gains, it has a pretty low Androgen Receptor Binding affinity (14).. I suppose, in this respect it can be compared to Winstrol (Stanozolol). As far as strength and agression goes, Halo is a great drug. It is especially useful on a cutting or strength cycle. It´s use for mass and weight gains have been pretty disappointing for most users, however. Fluoxymesterone administration is (unfortunately) accompanied by a reduction in thyroid binding globulin which causes associated decreases in T3, while the free T4 index remained totally unaltered; thus implying that thyroid function was unchanged. Remember, many anabolic steroids (notably Trenbolone) lower your T3 levels. In addition, during fluoxymesterone administration, there was a reduction in testosterone, gonadotropins and LH response to LHRH. Basal TSH did not vary, but there was a reduction in the peak and integrated TSH response to TRH. PRL levels tend to remain unchanged during fluoxymesterone use (8). Halo is of course suppressive to your HPTA, but I´ve found that in some studies where measurements were made of serum FSH, LH, testosterone, up to 20mgs per day of Halo did not suppress them measurably (9). This could possibly indicate the use of up to 20mgs/day of Halotestin without being in any great danger of suppressing endogenous hormones. Halotestin as Steroid Anyway, Halotestin is a testosterone derived steroid, and has an 11-beta group attached to it to inhibit aromatization, although it is particularly prone to being 5-alpha-reduced and may thus cause DHT related side effects, such as acne and hair loss. It is metabolized primarily by 6 beta-hydroxylation, 4-ene-reduction, 3-keto-reduction, and 11-hydroxy-oxidation. We know this by the identification of 4 particular metabolites and the tentative identification of at least 3 other metabolites. Detection of Halo in urine is possible for at least 5 days after a single 10 mg oral dose to previously untreated adult males, by monitoring the presence of 2 metabolites, since the parent drug is not detectable more than 1 day after the dose(12). However, the moral-compass of the athletic world, the IOC, has developed a test for fluoxymesterone metabolites that will detect them for up to 2 months after cessation of use. This item is not in high demand in bodybuilding except for as a pre-contest drug, and would more likely be found circulating in Athletic and Powerlifting circles, where it is more commonly used in a cycle. Halotestin (Fluoxymesteron) Profile [9-alpha-fluoro-11-beta-hydroxy-17-alpha-methyl-4-androstene-3-one,17b-ol] Molecular Weight: 336.4457 Formula: C20 H29 F O3 Melting Point: 240C Manufacturer: Upjohn, Various Date Released: 1957 Effective Dose:10-40mgs/day Active life:6-8 hours Detection Time: 2 months Anabolic/Androgenic ratio:1,900/850 References: 1. Treatment with anabolic steroids increases the activity of the mitochondrial outer carnitine palmitoyltransferase in rat liver and fast-twitch muscle. Biochem Pharmacol. 1991 Mar 1;41(5):833-5. 2. Effects of synthetic androgen fluoxymesterone on triglyceride secretion rates in the rat.Proc Soc Exp Biol Med. 1975 Jun;149(2):452-4. 3. Metabolism of anabolic steroids in humans: synthesis of 6 beta-hydroxy metabolites of 4-chloro-1,2-dehydro-17 alpha-methyltestosterone, fluoxymesterone, and metandienone. Steroids. 1995 Apr;60(4):353-66. 4. Influence of fluoxymesterone on in vitro erythropoiesis affected by leukemic cells.Exp Hematol. 1984 Mar;12(3):171-6. 5. [Erythropoietin in serum and urine in healthy persons and patients with chronic renal disease upon hypoxic stimulation and hypoxic stimulation after pretreatment with fluoxymesterone (author´s transl)] 6. Fluoxymesterone therapy in anemia of patients on maintenance hemodialysis: comparison between patients with kidneys and anephric patients. J Dial. 1977;1(4):357-66 7. Combination hormonal therapy with tamoxifen plus fluoxymesterone versus tamoxifen alone in postmenopausal women with metastatic breast cancer. An updated analysis.Cancer. 1991 Feb 15;67(4):886-91. 8. Effect of non aromatizable androgens on LHRH and TRH responses in primary testicular failure.Horm Metab Res. 1984 Sep;16(9):492-7. 9. The effect of synthetic androgens on the hypothalamic-pituitary-gonadal axis in boys with constitutionally delayed growth. J Pediatr. 1979 Apr;94(4):657-62. 10. The effect of synthetic androgens on the hypothalamic-pituitary-gonadal axis in boys with constitutionally delayed growth. J Pediatr. 1979 Apr;94(4):657-62. 11. Steroids and hematopoiesis. II. The effect of steroids on in vitro erythroid colony growth: evidence for different target cells for different classes of steroids. J Cell Physiol. 1976 Jun;88(2):135-43. 12. Testing for fluoxymesterone (Halotestin) administration to man: identification of urinary metabolites by gas chromatography-mass spectrometry. J Steroid Biochem. 1990 Aug 28;36(6):659-66. 13. Toxic effects of anabolic-androgenic steroids in primary rat hepatic cell cultures. J Pharmacol Toxicol Methods. 1995 Aug;33(4):187-95. 14. Relative binding affinity of anabolic-androgenic steroids: comparison of the binding to the androgen receptors in skeletal muscle and in prostate, as well as to sex hormone-binding globulin.Endocrinology. 1984 Jun;114(6):2100-6. 15. The relationship of androgen to the thyrotropin and prolactin responses to thyrotropin-releasing hormone in hypogonadal and normal men. J Clin Endocrinol Metab. 1981 Feb;52(2):173-6.