Structurally, Stenbolone actually resembles Primobolan, the major difference being that instead of a 1-methyl group, it has a 2-methyl group. This is a very common alteration, and actually is the one we see when comparing Masteron and Proviron. I don´t see why it was done with this particular steroid, though, as it´s an injectable, and this alteration is often used to increase oral availability without increasing liver-toxicity. Since it has been done, however, I´m speculating that you could actually ingest this steroid orally and still see some results.but why would you want to? Anyway, as we know, those Masteron and Proviron are very similar, but for that alteration I mentioned, so we can predict Stenbolone to actually produce very similar results to Primobolan.

Due to its structure (actually a 5-alpha reduced version of Boldenone), it can´t aromatize to estrogen, so it can´t cause estrogenic sides. However, the 1-2double bond in its structure (the same one we see with Boldenone) makes it less androgenic than I´d like and Stenbolone is only half as androgenic as Dihydrotestosterone. Thus, DHT-related side effects are also probably of no great concern. Clearly, this is a very safe drug in that regard, so it´s easy to see why Duchaine liked it so much, stating that if he had to pick one steroid to use for the rest of his life, it would be Anatrofin.

Stenbolone Acetate
     [2-methyl-5alpha-androst-1-en-3-one,17b-ol]
     Molecular Weight (base): 302.4558
     Molecular Weight (ester):60.0524
     Formula (base): C20 H30 02
     Formula (ester): C2 H4 O2
     Melting Point: N/A
     Manufacturer: Syntex (discontinued)
     Effective Dose: 350mgs-700mgs/week
     Active life: 3 days
     Androgenic/AnabolicRatio (estimate): 88:55

Source: steroid.com