Primobolan is one of those anabolic steroids which has a cult following not unlike the old original version of Masteron. Actually, as you can easily see from it´s anabolic:androgenic ratio below in the profile, it´s a pretty weak steroid but actually stronger(!) than Masteron in both regards. I don´t know anyone who has run both compounds at the same dose. We are probably justified in speculating that you´d probably get similar results from either of them, when you consider the fact that you are getting quite a bit less actual drug and more ester when you choose injectable Primobolan (which has the very long Enanthate ester attached to it) over Masteron (which has the very short propionate ester attached to it). In truth, I think part of the reason many Primobolan users have been disappointed is that they failed to use enough of it, for long enough. From it´s chemical structure and anabolic:androgenic rating, we can assume it is at least as effective as Masteron, on an equal Mg for mg basis. However, due to its ester (in the injectable version), it needs to be run for at least 12 weeks to see the full benefits from it. When you consider a measly dose of 400mgs of this stuff for 12 weeks will probably cost you around $500.

It´s easy to see why many people have tried to use less...and have been disappointed with their results. On the other hand, many competitive bodybuilders consider Primobolan indespensible to their pre-contest drug routine, and wouldn´t consider dieting without it. Anyway...I think the comparison to Masteron (another great precontest drug) is the best one we can make, with reference to expected gains and results.

Effects of Primobolan

One study performed on sheep involved administering 100mgs of Methenolone, and electronically stimulating their lats (electronic stimulation was used because they kept falling off the chin-up bars). Anyway, when compared with the lat muscles of sheep who didn´t receive Methenolone, the receiving group gained significantly more muscle mass as well as strength (1)(2). It´s also has a relatively high affinity for binding to the AR, actually binding better than testosterone (3). This ability to strongly bind to the AR may be why Primobolan is such a good "fat burner." Strong AR binding has been positively correlated with lypolysis (fat-burning) (8).

In addition, as this steroid can actually aid in reducing breast tumors, no ancillary products need be considered for use with Primobolan, and in fact, it may actually be a useful ancillary agent in it´s own right, similar to Masteron. Also, just like Masteron, Primobolan has no propensity to aromatize (convert to estrogen). Since it doesn´t aromatize, a lot of the side effects commonly associated with estrogen will not be of concern. This means water retention, acne, and gyno will be non-existent more or less. this lack of water retention combined with the slow and steady gains provided by Primo may help to explain why it has earned a reputation for creating quality muscle gains. This also helps to explain why it is so expensive. Although estrogenic sides are not a concern, hair loss still, remains a very real concern with Primobolan, as with many DHT-Derived steroids. Many primobolan fans always include Finasteride and Ketoconazole (shampoo) in cycles containing Primobolan.

Although nobody would ever suggest to use Primobolan as a bulking agent, it´s been studied as an agent to halt wasting and possibly reverse many of the adverse effects of anemia. It is a shocking failure in both areas, according to some of the case studies I´ve read, (5)(6) and this should come to no surprise to anyone. Anadrol reigns supreme in this area, and nobody in the athletic community would ever compare those two drugs. However, Michael Mooney and many other respected doctors who work with AIDS patients have found sufficient evidence to claim that Primobolan is an immune enhancer and as such is very useful for AIDS patients (not that the FDA cares...Primobolan is still not approved for sale in the United States). AIDS patients aren´t really in need of Bulking Drugs, so an immune enhancer like Primo which will add small, quality gains in muscle is perfect for them. And since we aren´t even going to vaguely consider the use of Primobolan as a bulking agent, clearly this leaves us with considering it primarily for use in gaining and maintaining lean tissue. It´s a great choice for this purpose, and many competitors have used it very successfully to retain muscle while on a calorie reduced diet. The reason Primo is so useful for this purpose is that one of its primary functions is to help your body retain nitrogen (7) at a greatly enhanced rate. The greater your nitrogen retention is, the more muscle you will build. In the case of using primo as a pre-contest drug, this nitrogen retention will help you retain muscle and ensure that your dieting preferentially favors fat loss over muscle loss.

Primobolan is a very unique steroid, as it is one of the few that comes in both an oral as well as an injectable version. I suppose Winstrol does also, but Primobolan actually has a different ester on the oral (acetate ) and injectable (Enanthate) versions. The oral version is one of the more interesting oral compounds I´ve looked into. For starters, it´s one of the few compounds available to athletes and bodybuilders which is both oral as well as non-17-alpha-alkylation. This alteration is (as I´m sure you remember from other stuff I´ve written) what generally makes oral steroids survive their first pass through your liver, but also makes them Hepatoxic (Liver  toxic). Well... oral Primo doesn´t have this feature, so it is very mild on your liver (actually it basically isn´t liver toxic at all), but also is largely destroyed by it, since 17 beta estrification and 1 alkylation is the method used to make this stuff orally available. You´ll need to take a lot of this stuff for it to be effective... 100mgs/day of the oral version is a safe estimate for reasonable gains& for women, you could get away with less; perhaps 25mgs/day. Even though the acetate ester has a 2-3 day active life, your liver will do some damage to oral primo, so every day dosing will still be necessary.

When men were given a 30-45mg dose of the oral version of Primo, they experienced a 15-65% decrease in gonadotropin levels (9).100mgs is a good dose for gains... well, you´ll also reduce your gonadotropin levels considerably. I have personally never understood why people recommend either oral or injectable Primobolan as a possible bridging compound for this reason... maybe at a too-low-to-do-anything dose of 10mgs it could be used as a bridge.

Primobolan Profile

(Methenolone)

     (Oral Version is + Acetate Ester)
     (Injectable Version is + Enanthate Ester)
     [17beta-Hydroxy-1-methyl-5alpha-androst-1-en-3-one]
     Molecular weight of base: 302.4558
     Molecular weight of Acetate ester: 60.0524
     Molecular weight of Enanthate ester: 130.1864
     Formula: C20H30O2
     Melting Point:
     Manufacturer: Schering
     Effective dose(oral): (Men)50-100mgs/day; (Women) 10-25mgs/day
     Effective dose (injectable): (Men) 350-600mgs/week; (Women) 100mgs/week
     Active Life: 10-14 days (injectable); 4-6hrs (oral)
     Detection Time: 4-5 weeks
     Anabolic/Androgenic Ratio (Range): 88:44-57

Source: steroid.com