960:165-510 vs testosterone by oral administration. 
7a-methyl-19-norandrostenedione, Mentabolan, MENT dione, Trestione.
It was first synthesized and tested for anabolic and androgenic activity in rats in 1963.  It was subsequently released as a “prohormone/designer steroid” by PHF/IBE in late 2011.
This is a prohormone to the black-market bodybuilding steroid and experimental contraceptive Trestolone, aka MENT. It’s been described on some internet forums as “MENT dione”, however since MENT is short for 7a-Methyl 19-Nor-Testosterone, this compound could more accurately be described as 7a-Methyl-19-Nor-Androstenedione, and given an acronym of it’s own like MENAD or MENORAD.
This prohormone is a “19-nor”, or nandrolone derivative, and differs from nandrolone in that this hormone has a 17-ketone, where nandrolone has a 17b-hydroxy function, and also has the addition of a 7a-methyl group. In the same way as “Boladrol” is a 7a-methylated dione version of methyl testosterone, this compound is a 7a-methylated dione version of nandrolone.
Please don’t confuse this compound (or the target steroid) with the widely-feared mibolerone, a.k.a. “cheque drops”, which is a 17a-methylated version of trestolone (or dimethylated nandrolone). While MENT has the 7a-methyl/19-nor combination that produces a far stronger steroid than either configuration does alone, it lacks the 17a-methyl group that tends to dramatically increase liver toxicity.
Effects should be similar to the injectable trestolone acetate. It’s a strongly anabolic, moderately androgenic compound which should elicit significant strength gains and increased accumulation of muscle mass at an appropriate dosage. Users may also experience mood changes, such as an increase in confidence and subjective well being, and/or an increase in workout aggression.
Side-effects may include those common to anabolic androgenic steroids, including but not limited to: blood pressure increases, HPTA disruption, adverse shifts in lipoprotein subfractions (increased LDL, lowered HDL cholesterol), acne, hair growth or loss. This product should not be used by women or teens. There’s evidence that MENT aromatizes to some degree,  so the estrogen-sensitive may wish to either avoid this compound or co-administer an aromatase inhibitor (AI) or selective estrogen receptor modulator (SERM).
One side-effect that many might fear from this compound is the loss of libido and/or erectile dysfunction often seen with 19-nor derivatives (known colloquially as “deca-dick”). On the contrary, tests conducted with the target hormone trestolone (MENT) have found that it had a positive mood, libido, and erection-stimulating effect similar to that of testosterone,  though this may not necessarily hold true with the supraphysiological doses used by bodybuilders.
Metabolism and Bioavailability:
As mentioned, this is a “dione” prohormone. In the body the ketone at C17 will be hydrolysed by 17b-hydroxysteroid dehydrogenase type 5 (17b-HSD5) into the active compound trestolone (MENT). Trestolone itself has been shown to be roughly 6 times as anabolic as methyl test by oral administration, and around 2.5 times as androgenic. 
Unlike steroids like testosterone and DHT, trestolone shows no affinity for SHBG,  so all of the converted compound in circulation should be bioavailable. For the same reason, it’s likely to have a short terminal half-life so frequent dosing is suggested.
As most will know, testosterone and similar delta-4 steroids are typically converted to stronger compounds like DHT and DHT derivatives by the enzyme 5-alpha reductase (5AR). 19-nor compounds are an exception to this rule, with 5a-reduced nandrolone (or 19-nor DHT) being a far less potent androgen than nandrolone itself.  The 7a-methylation of trestolone (and by extension Mentabolan) hinders the reduction of this double bond.  This means that the 7a-methyl group not only makes the compound stronger by increasing androgen receptor affinity,  but also reduces the ability of the body’s enzymes to break it down into weaker metabolites.
MENT is a strong compound for several reasons (including as previously discussed steric hindrance to 5a-reduction, and an inability to bind with SHBG), but the primary reason for its strength is the increased androgen receptor affinity caused by the conformational changes of the 7a-methyl group.  The same will be true of the prohormone to MENT; Mentabolan.