Methylnortestosterone Decanoate
A long-acting decanoate ester of 7-alpha-methyl-19-nortestosterone (MENT), a potent synthetic androgen that resists both aromatisation to a normal estrogen pattern and 5-alpha reduction. The parent MENT was investigated as a male contraceptive and androgen replacement agent; the decanoate ester extends its duration for depot delivery. It is a research-grade compound with very limited human characterisation in this esterified form.
01 Overview
7-alpha-methyl-19-nortestosterone (MENT, trestolone) is roughly ten times as potent as testosterone on a weight basis and does not undergo 5-alpha reduction, so it does not accumulate in prostate tissue the way testosterone does. It does aromatise, but to a more potent estrogen (7-alpha-methyl-estradiol), meaning estrogenic effects remain a concern. The acetate ester (trestolone acetate) is the better known form; a decanoate ester lengthens the release window for sustained depot dosing.
Human data specific to the decanoate ester are essentially absent; most evidence derives from MENT implant and acetate studies conducted for contraceptive and hypogonadism research. The compound is included as a member of the injectable 19-nor androgen family and should be regarded as poorly characterised in its long-ester injectable form.
02 Mechanism
The decanoate ester slowly releases MENT, an androgen receptor agonist about tenfold more potent than testosterone that is not a 5-alpha reductase substrate but does aromatise to a potent estrogen.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Low | 20–40 mg/wk | IM | MENT is far more potent than testosterone; doses are low. |
| Enhancement | 40–70 mg/wk | IM | Anecdotal; no validated protocol for the decanoate ester. |
Ester comparison
| Ester | Half-life | Injection freq. | Testosterone by mass |
|---|
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Potent anabolismMENT is highly anabolic and androgenic per milligram in animal assays. | ~10x testosterone by weight | Preclinical | |
| No prostate 5-alpha amplificationBecause it is not converted to a DHT-like metabolite, prostate effects differ from testosterone. | Not 5-alpha reduced | Preclinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| Estrogenic effects from potent metaboliteAromatisation to 7-alpha-methyl-estradiol can cause pronounced gynecomastia and water retention. | Moderate | Common | Preclinical | |
| Progestogenic effectsLike other 19-nor compounds it has progestogenic activity that can worsen gynecomastia and libido loss. | Moderate | Common | Preclinical | |
| Strong HPTA suppressionMENT was studied precisely because it profoundly suppresses spermatogenesis. | Severe | Universal | Preclinical |