Now this goal depends highly on how advanced one already is as a trainer and/or steroid user. Someone who is already 40 lb. more muscular than he could achieve naturally, and who wishes to add still more for the purposes of competitive bodybuilding, will simply find no use from a recommendation to use 500 mg/week of Sustanon

At best such a dose might allow him to maintain what he has, instead of slowly losing muscle while off drugs. Such an athlete will probably not achieve his goals with less than a gram per week of injectables, stacked with at least 50 mg/day of orals. And he may need more than this. He is already far beyond what he could attain naturally, and more yet will not come easily. 

Muscle and anabolic steroids

What of the person who, after several years of hard, quality training, is probably fairly close to his genetic limit under natural conditions? He would probably achieve excellent results with this same 500 mg/week dose of Sustanon, and undoubtedly would do so with some Methandienone added as well.
Another person may not even be close to his natural genetic limit in the first place, due to inconsistent or poor training, or novice status. Such a person can make excellent gains without anabolic/androgenic steroids (AAS) at all, and while AAS can increase the rate of gains, one cannot say that any particular drug regimen is necessary or advisable. 

Yet another person, who simply wishes to have an attractive physique and appearance by conventional standards, and highly values the condition of his skin and hair, would be poorly served by the advice to use Sustanon or Methandienone at any dose. The likely worsening of his skin and possible acceleration of hair loss would not be worth it. He would be better served with a milder drug, which would allow him to achieve his goals with minimal cosmetic or health risk. 

And what about the second goal: losing fat? Well, this goal is at cross-purposes with gaining muscle. One simply cannot gain nearly as much muscle on reduced calories as on higher calories allowing a fat gain of perhaps 1 lb/week. 

The person would be best advised to divide muscle gains and fat loss into separate phases. If a person is not at a level of muscularity beyond what he can attain naturally, AAS really are not necessary for dieting down to moderate body fat levels such as 8%. However, AAS use can make the dieting easier and faster, especially for natural endomorphs. 

It does not seem that much of a dose is required in this applicatio n. 250 mg/week Sustanon or 400 mg/week Primobolan will be effective. That however is not the case for individuals who are well beyond their natural limits. They will shrink much faster on low dose steroids than on high dose steroids while dieting, and anything less than a gram per week would be obviously much less effective than doses actually used (2-4 grams per week not being unusual in elite circles.)

Source:
Duchaine Daniel, Underground Steroid Handbook II, 2006
Hart Mick, Laymans Guides to Steroids
Hart Mick, Laymans Guides II - Return of the Syringe
Hart Mick, Laymans Guides III - Return of the Syringe
Hardcore, Complete Steroid Handbook, 2004