Halotestin
Active ingredient: Fluoxymesterone (Fluoxymesterone). Considered to be the strongest androgen and yet binds the androgen receptor weakly. The only controlled data comes from breast cancer therapy: a narrow advantage in response, none in survival, and in the larger study, none at all.
Auch bekannt als: Fluoxymesteron, Halo, Fluoxymesterone
What it is
Fluoxymesterone is a derivative of testosterone with three attachments: a fluorine atom at position 9, a hydroxy group at position 11, and a methyl group at C17. The molecular formula is C₂₀H₂₉FO₃. It was developed in the 1950s; It has been used clinically for hypogonadism and breast cancer in postmenopausal women, and the only controlled data on this substance come from this second use.
The methyl group on C17 makes the substance swallowable and puts a strain on it Liver, as with any oral steroid. The fluorine atom at C9 is special: it is the only halogen atom at this point among the common anabolic steroids, and it enhances the effect of the neighboring hydroxy group at C11.
How it works
The ratio does not hold up to the measurement
There is a circulating anabolic to androgen ratio of 1900 to 850 for fluoxymesterone, which makes the substance by far the strongest androgen. The displacement series in which such numbers arise says the opposite. On Androgen receptor of skeletal muscle and prostate, fluoxymesterone was one of the weak Binders, with less than 5 percent of the binding strength of the comparison substance, in the same group as Stanozolol and Methandienone.
The same work also removes the basis for the ratio: the ratio of binding in the muscle to that in the prostate was close to one for all steroids tested and usually only fluctuated between around 0.4 and 1.7. According to this measurement, a substance that has more than twice as strong an effect on the muscle as on the prostate does not exist, and a number like 1900 to 850 has no equivalent there. It was not possible to determine where it came from.
What of it? not follows: that the material appears weak. In metastatic breast cancer, 40 percent of patients responded to fluoxymesterone alone after tamoxifen failed. A substance that influences a tumor disease is not ineffective. It just doesn't seem to work through particularly strong receptor binding, and that's a difference.
No flavoring
Fluoxymesterone is not converted to estradiol to any significant extent. There is no estrogen-related water retention, and a aromatase inhibitors has nothing to inhibit. The reputation that the material makes you hard and dry has its basis in this and does not describe its own effect on the fabric, but the absence of another.
Aggression and drive
The most striking attribution to this substance is behavioral change: increased aggression, drive and competitive toughness. A study that would have measured this for fluoxymesterone could not be found in the literature reviewed here. For the substance class as a whole, a review lists increased sex drive and increased aggressive behavior among the most frequently self-reported effects in male athletes. This is a self-report and not a measurement, and it says nothing for this one substance.
What the studies show
There is nothing to train: no controlled examination, no dose determination, no measurement of strength or muscle mass. What there are are two large randomized trials in oncology, and they are unusually well done.
In metastatic breast cancer
238 postmenopausal women with metastatic breast cancer received either Tamoxifen alone or tamoxifen together with fluoxymesterone, 10 mg each twice daily. An objective response was seen in 50 of 119 with tamoxifen alone, i.e. 42 percent, and 63 of 119 with the combination, i.e. 53 percent. The average time until the disease progressed was 350 versus 199 days. Duration of response and survival did not differ, and androgenic side effects were greater with the combination.
The third arm is remarkable: 52 patients who had failed tamoxifen were then given fluoxymesterone, and 21 of them, or 40 percent, responded. The substance also works alone.
And in preventative treatment
The attempt to confirm this advantage in a larger and more important situation failed. 541 postmenopausal women with operated early, estrogen receptor-positive breast cancer received tamoxifen alone for five years or additional fluoxymesterone for one year. After an average of 11.4 years of follow-up, it was found no difference in relapse-free survival and none in overall survival; the adjusted risk ratio was 0.84 for relapse or death and 0.89 for death, both with confidence intervals including unity. As expected, masculinization occurred more frequently with fluoxymesterone.
This is an instructive couple. The first study found a narrow benefit in response and none in survival, and its authors wrote even then that the benefit was too small to justify the combination. The second, larger and longer observed, found none at all. A substance whose best documented benefit looks like this is not a strong active ingredient, but a weak one with clear side effects.
For the substance class as a whole, a review article describes strength increases of around 5 to 20 percent of the initial value and 2 to 5 kg of body weight with short-term administration, without any decrease in fat mass appearing to occur. It is not clear whether fluoxymesterone is at the top or bottom.
Dosage
- The only dose tested is 20 mg daily. 10 mg twice, for months to a year, in both randomized trials. The usual 20 to 40 mg daily in sports starts at the upper edge of the tested range and goes beyond it.
- The tested duration of use is one year, not two weeks. This does not relativize the common rule of thumb in terms of safety: the patients were monitored by a doctor and their alternative was progressive cancer. However, it shows that the usual limit of two to four weeks is not a measured limit.
- Not next to a second oral steroid. Two 17-alpha-alkylated preparations attack the same place in the liver, and the benefit of the second is disproportionate to this substance.
- An aromatase inhibitor has no target here. Without significant aromatization, there is nothing to inhibit; it just lowers estradiol from other sources in the stack.
- For women, the fabric is the worst choice in the category. As expected, masculinization occurred more frequently in the large study, and voice changes do not go away.
- Initial values before the first tablet. transaminases, Bilirubin, alkaline phosphatase, blood pressure, lipid profile and Hematocrit.
Side effects
Liver
What happens: The methyl group at C17 interferes with the removal of bile salts from the liver cell; A build-up of bile occurs with jaundice and itching with little cell death. Fluoxymesterone is considered to be particularly stressful for the liver.
What it depends on: About the alkylation, the dose and the duration. What follows from this is: A study that would have used liver values under fluoxymesterone as an endpoint could not be found in the literature reviewed, and a search for case reports of liver damage under this substance did not yield any results. The reputation as the most liver-toxic representative of the class is therefore not proven; it follows from the structure it shares with the other oral steroids. What you can do: transaminases, Bilirubin and alkaline phosphatase at baseline and after four weeks. If yellowing, dark urine or itching occurs, discontinue use immediately. For TUDCA There is no controlled study on this clinical picture.
Masculinization, especially among women
What happens: Fluoxymesterone is a pure androgen without estrogen content. In both randomized trials, more androgenic side effects occurred with the combination with fluoxymesterone than with tamoxifen alone, and masculinization was specifically mentioned in the larger one.
What it depends on: Of dose and duration, and of gender. For the study participants, 20 mg daily was enough to make the effect visible. What follows from this is: In men it manifests itself as acne, increased body hair and accelerated hair loss, in women it also manifests itself as deepening of the voice and enlargement of the clitoris, and these two do not go away. What you can do: For women, the only effective way to deal with it is abstinence; At the first sign of a voice change, the damage has already been done. For men, only local remedies and discontinuation help against hair loss.
Blood pressure, blood lipids and blood count
What happens: Oral 17-alpha-alkylated steroids increase the breakdown of HDL particles in the liver; that HDL falls, LDL rises. For this class of substances, a review article names increased blood pressure and reduced HDL, including its subfractions, as the significant risk changes; Androgens also stimulate blood formation, without this being reflected in better endurance performance.
What it depends on: From the oral route and from the dose. No figures specifically for fluoxymesterone could be found in the literature reviewed. What follows from this is: The last sentence is important for this material because it was used in martial arts because of the increasing hemoglobin: An increase in hemoglobin and hematocrit has been described with anabolic steroids, but no improvement in endurance performance has been observed. What you can do: Lipid profile, blood pressure and Hematocrit before the start and after four weeks, see Cardiovascular risks associated with AAS.
Your own axis
What happens: An supplied androgen drives the HPTA axis down, LH and FSH fall. Since fluoxymesterone does not provide estradiol, androgen and estrogen fall at the same time if nothing else is present.
What it depends on: Of dose and duration. For this class of substances, the disruption to your own testosterone and gonadotropin production can persist for months after you stop using it. What follows from this is: If you use the substance for a few weeks, as is usual, the axis is still suppressed and the recovery takes longer than the application. What you can do: Determine testosterone and LH before starting and after discontinuation and plan withdrawal. For the restart HCG and Clomiphene the established means.
Classification
Halotestin lives from a number that doesn't exist. The circulating ratio of 1900 to 850 has no equivalent in the only larger displacement series; There, fluoxymesterone is one of the weak binders on the androgen receptor. And the concept that the number conveys does not hold up to the same measurement: muscle and prostate hardly differ in their receptors.
What the substance has been proven to be able to do is in oncology, and it is modest. In addition to tamoxifen, he increased the response rate in metastatic breast cancer from 42 to 53 percent without increasing survival, and his own authors considered that too little to recommend the combination. In the larger study with eleven years of follow-up, there was no advantage at all. Given alone, it worked in 40 percent of patients for whom tamoxifen had failed. This is a real effect and not an extraordinary one.
The attribution that matters in sport is also the least well-documented. The fact that fluoxymesterone increases aggression and competitive toughness is self-reported by the scene; no measurement for this could be found. For a substance that is taken almost exclusively for this effect, this is the crucial gap.
What would decide the matter would be an experiment as is usual in psychopharmacology: the same person, two phases, blinded, with standardized questionnaires on irritability, drive and mood, as well as the strength values. For a substance whose main desired effect takes place in the head, blinding would be crucial, and it is precisely this that is missing.
Sources
- Saartok T, Dahlberg E, Gustafsson JA. 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. PubMed
- Ingle JN et al. Randomized clinical trial of tamoxifen alone or combined with fluoxymesterone in postmenopausal women with metastatic breast cancer. J Clin Oncol. 1988. PubMed
- Ingle JN et al. Randomized trial of tamoxifen alone or combined with fluoxymesterone as adjuvant therapy in postmenopausal women with resected estrogen receptor positive breast cancer. North Central Cancer Treatment Group Trial 89-30-52. Breast Cancer Res Treat. 2006. PubMed
- Hartgens F, Kuipers H. Effects of androgenic-anabolic steroids in athletes. Sports Med. 2004. PubMed
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