MENT (methylnortestosterone acetate)
MENT, short for methylnortestosterone (acetate), is a synthetic anabolic steroid derived from nandrolone. This agent is also called trestolone acetate, although not as commonly. The trivial name methylnortestosterone is vague, and can also be applied to other steroids. In this case the “methyl’ in the name, which is commonly associated with C-17 alpha alkylated androgens like methyltestosterone, methandrostenolone, or oxymetholone, is referring to a modification at C-7. This gives MENT a considerably different appearance than 17methylnoretestosterone (Orgasteron). Of most obvious significance is its method of use. Although perhaps possessing a moderate level of oral bioavailability, this nandrolone derivative was not designed for oral administration. It is much more effective when administered to the body directly, by injection, implant, or transdermal gel. In character, MENT is a strongly anabolic steroid, which is accompanied by moderate androgenic and estrogenic properties.
General steroid potency is usually increased with 7methylation, a trait well illustrated with MENT. When methylation increases steroid potency it is usually due to one or a couple of things, most notably increased resistance to hepatic metabolism (breakdown) or reduced affinity for constrictive binding proteins. In the case of MENT, we see a steroid with relatively fast metabolic breakdown, but no binding to SHBG (Sex Hormone-Binding Globulin).1 Therefore, reduced binding to serum proteins seems to be partly responsible for making MENT a more potent steroid. When assayed in 1963, scientists reported an anabolic effect that was between 3.5 and 23 times greater than testosterone, while being only 3-6 times more androgenic.2 3 When investigated in primates in 1998, it was shown to have 10 times more anabolic potency than testosterone, with only 2 times the stimulatory action on the prostate.4
Its relative androgen receptor binding affinity was investigated a year later, and provided further explanation for the strong anabolic effect of this steroid. Here, MENT was shown to bind the androgen receptor more strongly than testosterone, nandrolone, or dihydrotestosterone.5
MENT (methylnortestosterone acetate) was first described in 1963.6 The early 1960’s were part of the heyday of anabolic steroid development, with new compounds being introduced into the journals almost every week. Like a great many of the effective steroids studied during this era, however, MENT didn’t make its way to becoming a commercial drug product. For about four decades it sat gathering dust on the bookshelves, next to many other effective but anonymous compounds. Historically, lack of early financial support has been a death sentence for anabolic steroids. If a company isn’t there in the beginning to spend the millions necessary to develop it into an actual prescription product, it isn’t going to go anywhere later on. The money simply wasn’t there for MENT in the 1960s, and it died. For a long time this agent remained a “nothing’ in the world of steroids.
But things changed for MENT around the turn of the century, in a very dramatic fashion. On October 30, 2000, international drug giant Schering AG (now Bayer) made a public announcement that it had entered into a partnership to research, develop, and market methylnortestosterone acetate for both male contraceptive and hormone replacement use. This followed several years of sporadic but positive studies on this agent. The ball was set in motion, and this old steroid, which scientists had ignored for over thirty years, was suddenly amidst a hotbed of new research and speculation, the likes of which it had never seen before. In their press release, Schering AG makes promise of a new androgen that offers the anabolic and endocrine benefits of an injectable testosterone, but with less prostate growth, and more patient comfort.
In other words, Schering is saying that MENT looks to be an easier to administer and equally useful steroid as testosterone, without the same issues concerning androgenicity.
The principle attraction Schering/Bayer has to MENT is probably not necessarily its potency, but its ability to duplicate the positive effects of testosterone on muscle mass and male sexual function while minimizing stimulatory action on the prostate. Prostate cancer and benign prostate enlargement are very common problems among males in the U.S., and both diseases are fueled at least partly by androgens. This has led to a great deal of caution when it comes to androgen replacement therapy in older men. Although the medical data is still inconclusive in this regard, many physicians fear that the androgenicity of testosterone may lead to ill effects. After all, increases in PSA values with testosterone use in older men are well documented.7 Perhaps MENT is being introduced to alleviate this concern. Noticing the lower relative androgenicity of MENT, researchers concluded over a decade ago that it might be a far better option for hormone replacement therapy. To quote the researchers from the NY Center for Biomedical Research exactly, ‘We conclude that the use of MENT instead of T for androgen replacement therapy could have healthpromoting effects by reducing the occurrence of prostate disease.’8 This is quite a statement, especially when we remember it concerns the use of a synthetic anabolic steroid.
Looking a little more closely at some of the recent studies conducted on MENT, we see a general trend of success and relative safety. Perhaps the most noteworthy to examine is the multinational clinical study that was conducted between 2002 and 2003.9 It involved the use of MENT implants as long-term contraceptives in males. In this experiment, thirty-six men were enrolled in three separate clinics residing in Germany, Chile, and the Dominical Republic (12 men at each). The study protocols itself called for the use of the implants for 6, 9, or 12 months, and required periodic examinations to measure their effects and potential risks. Three different dosages were used, which consisted of administering one, two, or four implants at the onset of the investigation. Each implant is designed to deliver about 400mcg of steroid per day, which equates to daily doses of 4mg, .8mg, or 1.6mg of steroid. The release rate is slowly reduced as the Implant loses surface area, however, reaching approximately 200mcg per day by the one-year mark.
The results of the clinical trial were very promising. Four MENT implants (1.6mg/day) suppressed spermatogenesis with similar effectiveness as testosterone implants, testosterone enanthate injections, and testosterone undecanoate injections (all of which have been investigated successfully as contraceptives).
MENT was able to produce azoospermia in 82% of treated subjects, a figure that was actually higher than reported with 200 mg of testosterone enanthate per week (which produced azoospermia in 65-66% of normal male subjects by 6 months). As far as negative side effects, they were few.Two subjects noted increases in blood pressure that went outside the normal range, and one was forced to discontinue the study because of it (though no ill effect was noted). Otherwise, there was generally just a very small rise in systolic pressure (+4.8), and no significant changes in lipids (including cholesterol and triglycerides) or PSA values. Furthermore, prostate volume was slightly reduced (not increased) in all groups. Liver enzymes were increased slightly, but stayed within the normal range in all subjects. The mean time to the recovery of normal sperm production after discontinuance was 3 months, similar to that reported in a 1990 World Heath Organization study with 200 mg weekly of testosterone enanthate. Overall, MENT performed admirably, with a very notable (acceptable) level of effect, and minimal side effects. And what is more, the drug may be effective when being implanted as infrequently as once per year.
Another study of interest examined the ability of MENT implants to restore sexual behavior and function in hypogonadal (low testosterone) men.10 This, of course, is one of the principle objectives of androgen replacement therapy. This investigation took place in two clinics, one based in Ireland and the other Hong Kong. Twenty men participated in total, 10 at each location. The study was a double crossover investigation comparing the effects of testosterone enanthate (200 mg every 3 weeks) to that of two MENT implants (delivering .8mg of drug per day). This means that each of the twenty men had an opportunity to try both drugs, which were taken on two separate occasions between washout periods. Only minor differences in response were noted between MENT and conventional androgen replacement therapy, and both drugs were effective in restoring sexual behavior and erection frequency. MENT, at a dosage of 2 implants delivering approximately .8mg of drug per day, proved to be an effective option for androgen replacement therapy.
If Bayer does market this drug as an implant, it will be impractical to use for bodybuilding purposes. At best it will need to be broken down and made into an injectable somehow. The clinical study discussed above used implants containing about 140 mg of steroid each. Given the same in a production drug, more than one implant will be needed for a workable cycle. There is some investigation into its use as an oral,11 which does seem feasible (although not ideal from a cost effectiveness standpoint). The key to this steroid’s success with bodybuilders will really be the development of a commercial injectable.
This will likely follow the release of Bayer’s product; perhaps even precede it. The raw powder is already available from suppliers overseas, so it should not take long for some veterinary or underground manufacturer to perceive value in this new agent. An acetate version will probably be closely followed by a sloweracting MENT ester, perhaps even something basic like MENT cypionate or MENT enanthate.
MENT is not yet available as a prescription drug product.
MENT is a modified form of nandrolone. It differs by the addition of a methyl group at carbon 7-alpha to increase steroid potency and relative androgenicity. MENT generally refers to methylnortestosterone acetate, modified with the addition of carboxylic acid ester (acetic acid) at the 17-beta hydroxyl group to help extend the activity of the steroid during injection or implantation.
Side Effects (Estrogenic):
MENT is aromatized by the body, and converts to a synthetic estrogen with a high level of biological activity (7alpha-methylestradiol).12 As a result, it is a moderately estrogenic steroid. Gynecomastia is possible during treatment, particularly when higher doses are used. At the same time water retention can become a problem, causing a notable loss of muscle definition as both subcutaneous water retention and fat levels build. Sensitive individuals may want to keep the estrogen under control with the addition of an anti-estrogen such as Nolvadex®. One may alternately use an aromatase inhibitor like Arimidex® (anastrozole), which is a more effective remedy for estrogen control. Aromatase inhibitors, however, can be quite expensive in comparison to standard estrogen maintenance therapies, and may also have negative effects on blood lipids. Note that there is no mention of gynecomastia in any of the human clinical studies that have been conducted on this agent. Estrogenicity does not appear to be much of a problem when used at appropriate therapeutic dosages.
Note that studies have also shown MENT to strongly bind the progesterone receptor, as well as to produce progestational effects on uterine weight in immature rabbits.13 Further examination, however, confuses this determination. The effects of MENT on uterine weight were not blocked by concurrent use of an anti-progestin (mifepristone) or anti-estrogen, suggesting that neither progestational nor estrogenic activity was responsible for this effect. Given the use of only this one limited model, the known binding of MENT to the progesterone receptor, and the tendency for nandrolone-derived drugs to offer at least some progestational activity, moderate activity will be assumed until it can be discounted.
The side effects associated with progesterone are similar to those of estrogen, including negative feedback inhibition of testosterone production and enhanced rate of fat storage. Progestins also augment the stimulatory effect of estrogens on mammary tissue growth. There appears to be a strong synergy between these two hormones here, such that gynecomastia might even occur with the help of progestins without excessive estrogen levels being present. The use of an antiestrogen, which inhibits the estrogenic component of this disorder, may be sufficient to mitigate gynecomastia caused by progestational anabolic/androgenic steroids.
Side Effects (Androgenic):
Although classified as an anabolic steroid, androgenic side effects are still possible with this substance. This may include bouts of oily skin, acne, and body/facial hair growth. Anabolic/androgenic steroids may also aggravate male pattern hair loss. Individuals sensitive to the androgenic effects of this steroid may find a milder anabolic such as Deca-Durabolin to be more comfortable. Women are additionally warned of the potential virilizing effects of anabolic/androgenic steroids. These may include a deepening of the voice, menstrual irregularities, changes in skin texture, facial hair growth, and clitoral enlargement.
Note that one well-understood function of 7-methylation is to block steroid 5-alpha reduction. As such, this derivative of nandrolone cannot be converted to a ‘dihydro’ metabolite.14 With nandrolone and most of its analogs, this reduction means a less androgenic steroid. Dihydronandrolone is weaker than nandrolone, so relative binding is reduced in target tissues with high reductase concentrations. Not being able to convert to a weaker steroid here, MENT is going to display more relative androgenicity than nandrolone. Reductase inhibitors, likewise, will not affect the relative androgenicity of MENT. Greater androgenicity was deemed a desirable trait during development, as it allows MENT to more effectively support male sex characteristics and libido compared to the weakly androgenic nandrolone.
Side Effects (Hepatotoxicity):
MENT is not a c17-alpha alkylated compound, and not known to have hepatotoxic effects. Liver toxicity is unlikely.
Side Effects (Cardiovascular):
Anabolic/androgenic steroids can have deleterious effects on serum cholesterol. This includes a tendency to reduce HDL (good) cholesterol values and increase LDL (bad) cholesterol values, which may shift the HDL to LDL balance in a direction that favors greater risk of arteriosclerosis.
The relative impact of an anabolic/androgenic steroid on serum lipids is dependant on the dose, route of administration (oral vs. injectable), type of steroid (aromatizable or non-aromatizable), and level of resistance to hepatic metabolism. MENT is likely to have a moderate effect on the hepatic management of cholesterol due to its aromatizable nature and route of administration. Anabolic/androgenic steroids may also adversely affect blood pressure and triglycerides, reduce endothelial relaxation, and support left ventricular hypertrophy, all potentially increasing the risk of cardiovascular disease and myocardial infarction.
To help reduce cardiovascular strain it is advised to maintain an active cardiovascular exercise program and minimize the intake of saturated fats, cholesterol, and simple carbohydrates at all times during active AAS administration. Supplementing with fish oils (4 grams per day) and a natural cholesterol/antioxidant formula such as Lipid Stabil or a product with comparable ingredients is also recommended.
Side Effects (Testosterone Suppression):
All anabolic/androgenic steroids when taken in doses sufficient to promote muscle gain are expected to suppress endogenous testosterone production. Without the intervention of testosterone-stimulating substances, testosterone levels should return to normal within 1-4 months of drug secession. Note that prolonged hypogonadotrophic hypogonadism can develop secondary to steroid abuse, necessitating medical intervention.
The above side effects are not inclusive. For more detailed discussion of potential side effects, see the Steroid Side Effects section of this book.
MENT has not yet been developed into a commercial drug product. Prescribing guidelines are unavailable. MENT is a relatively potent steroid, so an effective dose for bodybuilders is going to be small. As a drug 10 times more anabolic than testosterone by some studies, and 20 times more effective at suppressing spermatogenesis than testosterone enanthate in others, we should commonly see daily doses under 10 mg (maybe 3-6mg most commonly). If prepared as an oil-based injectable (with acetate ester), this would mean shots of roughly 10-20 mg every two to three days. Compare this to trenbolone, which is usually given in doses of 75-100 mg per shot under the same schedule (and this is a particularly potent steroid).
Some might find good effect at 10 mg daily or above, although high doses will likely amplify potential side effects, and are not recommended.
MENT should stack well with a variety of different steroids, possibly for both cutting and bulking phases of training depending on individual sensitivity to its estrogenic and progestational properties. For simplicity, this might mean using it with drugs like testosterone cypionate or enanthate (200-400 mg per week), Dianabol (20-35 mg per day), or Anadrol (50-100 mg per day) when looking for sheer size, milder anabolics like nandrolone decanoate or boldenone undecylenate (200-400 mg per week) for lean mass, or nonaromatizable drugs like Primobolan (200400 mg per week), Winstrol (20-35 mg per day), or Anavar (15-20 mg per day) while cutting. Remember that c-17 alpha alkylated substances impart some hepatotoxictiy, and may greatly amplify the negative effects of steroid therapy on serum lipids.
MENT has not yet been developed into a commercial drug product. Prescribing guidelines are unavailable. Given its high level of potency, effective doses in women would likely be measured in microgram amounts. The drug would also generally be taken in cycles lasting 4 weeks or less. Note that virilizing side effects are still possible with primarily anabolic substances, and need to be carefully monitored.
No legitimate medical preparation containing MENT is yet available. This compound may be available on the black market as an underground steroid.
1 Pharmacokinetics of 7a-methylnortestosterone in men and cynomolgus monkeys. Kumar N. et al. J Androl 18:352-58.
2 Al Segaloff. Steroids 1,299 (1963).
3 J A Campbell, SC Lyster et al. Steroids 1,317 (1963).
4 Prostate-sparing effects in primates of the potent androgen 7amethylnortestosterone: A potential alternative to testosterone for androgen replacement and male contraception. Cummings D, Kumar N et al. J Clin Endocrinol Metab. 83:4212-19:(1998).
5 7alpha-methyl-19-nortestosterone, a synthetic androgen with high potency: structure-activity comparisons with other androgens. Kumar N. et al.L Steroid Biochem Mol Biol. 1999 Dec 31;71(5-6):213-22.
6 Lyster S C, et al. Acta Endocrin (Kbh) 43 (1963):399. 7 Transdermal testosterone improves sexual function, mood, muscle strength, and body composition parameters in hypogonadal men. J. Clin Endocrinol. Metab. 85:2839-53.
8 7alpha-methyl-19-nortestosterone: an ideal androgen for replacement therapy. Sundaram K, Kumar N, Bardin CW. Recent Prog Horm Res. 1994;49:373-6.
9 A clinical trial of 7a-methyl-19-nortestosterone implants for possible use as a long-acting contraceptive for men. S. Eckardstein, G Noe et al. J Clin Enocrinol Metab 88:5232-39:(2003).
10 7a-methyl-19-nortestosterone maintains sexual behavior and mood in hypogonadal men. R.A. Anderson, C.W. Martin et al. J Clin Endocrinol Metab. 84:3556-62(1999).
11 ‘Structure-activity relationship study of human liver microsomesctalized hydrolysis rate of ester prodrugs of MENT by comparative molecular field analysis (COMFA). Bursi R. Grootenhuis A. et al. Steroids 2003 Mar;68(3):213-20.
12 Aromatization of 7alpha-methyl-19-nortestosterone by human placental microsomes in vitro. Kumar N. LaMorte et al. J Steroid Biochem Mol Biol. 1994 Feb;48(2-3):297-304.
13 Estrogenic and progestational activity of 7-alpha-methyl19nortestosterone, a synthetic androgen. Beri R, Kumar N, Savage T. et al. Steroid Biochem Mol Biol. 1998 Nov;67(3):275-83.
14 Different patterns of metabolism determine the relative anabolic activity of 19-norandrogens. Sundaram K, Kumar N. et al. J Steroid Biochem Mol Biol. 1995 Jun;53(1-6):253-7.