Mibolerone
Active ingredient: Mibolerone. Heat suppressant approved for female dogs, effective in microgram quantities. Binds the androgen and progesterone receptors and is hardly bound in the blood. The acute attack of aggression for which it is taken has never been measured.
Auch bekannt als: Mibolerone, Cheque Drops, Dimethylnandrolon, 7,17-Dimethyl-19-Nortestosteron
What it is
Mibolerone is 7α,17α-dimethyl-19-nortestosterone, so Nandrolone with two additional methyl groups: one at C7, which enhances the effect on the receptor, and one at C17, which makes the substance swallowable. The molecular formula is C₂₀H₃₀O₂.
It is a veterinary medicine. It was approved for the suppression of heat in bitches, and it has also been studied in this application. There has never been an approval and never a study for humans. In addition, it serves as Metribolone, as a laboratory ligand for determining androgen receptors.
How it works
At the receptor
The binding properties of this substance have been unusually well studied because it should be useful as a measuring tool. It binds to the rat uterus and rat prostate Androgen receptor specific and with high affinity. It binds to glucocorticoid receptors not. In tissue from calf uteruses and human breast tumors, however, it binds both the androgen and progesterone receptors.
A second finding from the same work is more important for dosage than it initially sounds: different than Dihydrotestosterone Mibolerone binds the human sex hormone binding globulin practically not. Testosterone is largely bound in the blood and is therefore ineffective; This buffer does not apply to this material. What is given is free, and that is part of the explanation for why it works in microgram amounts.
The progestin side
That Mibolerone also binds the progesterone receptor, This substance is not just a side note from the 19-nor structure, but also fits the application: Suppressing a bitch's heat is exactly what you expect from a gestagen effect.
The binding patterns differed between rats and calves, which the authors attribute to species-specific differences in progesterone receptors. Transmission from one species to another is particularly uncertain with this receptor, and there is nothing available for humans other than the findings on the breast tumor tissue.
Aggression and what is known about it
This substance's reputation is based almost entirely on an effect in the head: an acute surge of aggression and drive, which is why it is taken immediately before a maximum attempt. There is no measurement of this, neither for Mibolerone nor even for a short-term active ingredient of this type.
What there is is the best controlled work on androgens and mood. 28 men with normal hormonal status alternately received a single injection of 1000 mg testosterone undecanoate or a placebo, blinded. Testosterone levels increased from 20.7 to 37.5 nmol per liter. The mood changes were detectable, but small: Anger and hostility increased on average from 7.48 to 10.71, and fatigue decreased. Aggressive behavior did not increase. This is a different substance, a different time frame and a different dose, and it does not refute the Mibolerone reports. But it shows how small the measured effect is if someone measures it blindly instead of asking about it.
What the studies show
There is nothing to humans. No controlled study, no case series, no dose determination, no measurement of strength, mood or side effects. What there is is the dog approval examination, and it is more informative than it sounds.
The dose in question
In female Beagle dogs, Mibolerone reliably suppressed heat when immature animals received 60 micrograms daily and adult animals received 200 micrograms daily for up to 730 days. Just 20 micrograms daily prevented heat in 70 percent of cases. In addition to the suppression of heat, a prolonged interval between cycles, vaginal discharge and a Dose-dependent enlargement of the clitoris. Decreased post-treatment pregnancy rates occurred only in animals given 20 micrograms for two years; The puppies born afterwards were outwardly unremarkable.
These numbers are the actual findings of this article. An adult beagle weighs around ten kilograms, and for him 200 micrograms a day is enough to shut down the entire sexual cycle. The amounts mentioned in strength training are of the same order of magnitude, with a body weight that is many times higher. Anyone who doses this substance is not in the range of a weak effect, but in an amount that will stop a dog from reproducing for two years.
The transmission from the dog to humans does not go far: different species, different gender, different question, and the authors reported neither liver values nor blood lipids. What it carries is the magnitude of the effective amount, and this is where most errors occur with this substance.
For the substance class as a whole, a review article describes short-term administration increases in strength of around 5 to 20 percent of the initial value and 2 to 5 kg of body weight, as well as increased blood pressure, reduced HDL cholesterol and a disruption in one's own hormone production, which can last months after discontinuation. She cites increased sex drive, acne, increased body hair and increased aggressive behavior as the most common self-reported effects of male athletes.
Dosage
- There is no dose for humans. Neither one that has been tested nor one that has been handed down from a medical application. All information circulating is scene practice.
- The reference size is micrograms, not milligrams. For dogs, 60 to 200 micrograms daily are sufficient for a complete hormonal effect. An error by a factor of a thousand with such a dosed substance is not a theoretical risk, but rather the most likely application error.
- There is no SHBG buffer. Unlike testosterone, Mibolerone is hardly bound in the blood; what is given works. This explains the small amount and the small margin between effective and too much.
- The purpose is an impact that no one has measured. Those who take the substance because of an attack of aggression rely on self-reports, and the only blinded study on androgens and aggression found no increase in aggressive behavior.
- Not next to a second oral steroid. Mibolerone is methylated at C17 like Methandienone and Methasterone and thus attacks the same place in the liver.
- The material is not suitable for women. In the female dog, clitoral enlargement was dose-dependent and occurred regularly. This change does not reverse in humans.
Side effects
Your own axis
What happens: An supplied androgen drives the HPTA axis down. In the female dog, mibolerone shut down the entire sexual cycle for up to two years, and after weaning, the pregnancy rate was reduced in one of the groups.
What it depends on: Of dose and duration. There is no measurement for humans; For this class of substances, the disorder can persist for months after discontinuation. What follows from this is: A substance that suspends an entire cycle in microgram quantities is not a candidate for the assumption that a short application will have no consequences. What you can do: Determine testosterone and LH before starting and after stopping. For the restart HCG and Clomiphene the established remedies, both requiring a prescription.
The gestagen effect
What happens: In addition to the androgen receptor, Mibolerone also binds the progesterone receptor. Partial progestin action may affect libido and erection more than testosterone or estradiol levels suggest, and may contribute to the growth of mammary tissue without the involvement of estradiol.
What it depends on: Of dose and duration. What is measured is the bond, not the effect on humans, and the bond patterns differed between the species examined. What follows from this is: Anyone who expects this page is correctly interpreting a loss of libido with normal estradiol. A aromatase inhibitors doesn't attack it. What you can do: If there is a feeling of tension behind the nipple or a lack of recovery, testosterone, estradiol and Prolactin let it be determined together before a cause is assumed.
Liver
What happens: In other oral steroids, 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.
What it depends on: Of dose and duration. Neither a case report nor a measurement could be found for Mibolerone itself; The approval test in the dog did not report liver values. What follows from this is: For a substance that works in microgram quantities, a very small absolute amount passes through the liver, and this differs from substances that are taken in double-digit milligram quantities. This doesn't serve as an all-clear because it was never checked. What you can do: transaminases, Bilirubin and alkaline phosphatase before the start and during the course. If yellowing, dark urine or itching occurs, discontinue use immediately.
Blood pressure, blood lipids and the application situation
What happens: For the substance class, a review article mentions increased blood pressure and reduced blood pressure HDL cholesterol as the relevant risk changes. In addition, this substance has the special feature of its use: it is taken immediately before maximum exertion, i.e. exactly when blood pressure and heart rate reach their highest anyway.
What it depends on: From the dose and from the strain. There is no measurement for Mibolerone. What follows from this is: The temporal combination of active ingredient and maximum load is not as pronounced for any other steroid in this category, and it is the part of use for which there is the least data. What you can do: Measure blood pressure before and during the course, see Cardiovascular risks associated with AAS. If high blood pressure or a heart condition is known, the combination of this substance and a maximum attempt is the worst possible option.
Classification
Mibolerone is a heat suppressant approved for dogs, and the most important sentence about its use in humans is a number: For a ten-kilogram female dog, 200 micrograms a day is enough to stop the sexual cycle for two years. Anyone who orients themselves on this scale has an idea of what they are dealing with.
More is known about the receptor than most substances in this category, and that's because it was intended as a measurement tool. It binds the androgen receptor with high affinity, not the glucocorticoid receptor, but rather the progesterone receptor, and it is hardly bound in the blood. The last two points explain the progestin side and the small effective amount.
The reason for which it is taken is also the most poorly documented. There is no measurement of the acute surge in aggression and drive, and the best blinded study on androgens and behavior found only minor changes in mood and no increase in aggressive behavior after supraphysiological testosterone administration. Anyone who expects an effect that would not survive blinding should know that the expectation itself is part of it.
What would decide the matter would be exceptionally easy to build with this material and yet has never been built: the same athlete, two days of testing, blinded, with force measurement and a standardized questionnaire. For a substance whose desired effect occurs exclusively through experience, blinding is not a detail of the experimental setup, but the whole question.
Sources
- Traish AM, Mueller RE, Wotiz HH. Binding of 7 alpha, 17 alpha-dimethyl-19-nortestosterone (mibolerone) to androgen and progesterone receptors in human and animal tissues. Endocrinology. 1986. PubMed
- Sokolowski JH, Geng S. Biological evaluation of mibolerone in the female Beagle. Am J Vet Res. 1977. PubMed
- O'Connor DB, Archer J, Wu FC. Effects of testosterone on mood, aggression, and sexual behavior in young men: a double-blind, placebo-controlled, cross-over study. J Clin Endocrinol Metab. 2004. PubMed
- Hartgens F, Kuipers H. Effects of androgenic-anabolic steroids in athletes. Sports Med. 2004. PubMed
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