Like methandrostenolone (Dianabol),

Oxymetholone
does not bind well to the androgen receptor (AR), and most of the
anabolism it provides is via non-AR-mediated effects. It is therefore a
Class II steroid and is best stacked with a Class I steroid. The drug
appears to give the same benefits as Dianabol. Unlike Dianabol,
however, it seems that oxymetholone is progestagenic. It has been
observed to cause nipple soreness or to aggravate gynecomastia even in
the presence of high dose antiestrogens, strongly suggesting that the
effect is not estrogenic. That effect can be reduced by concurrent use
of stanozolol (Winstrol), which is anti-progestagenic. This
progestagenic effect of oxymetholone is only a concern when using
aromatizing steroids. With androgens such as Primobolan, oxymetholone
stacks very nicely and is a surprisingly friendly drug. In contrast,
with testosterone it is a very harsh drug.

Oxymetholone does not convert to estrogen, and thus antiestrogens
are not required if no aromatizable AAS are being used. However, in
concert with aromatizing drugs, oxymetholone is notorious for worsening
“estrogenic” symptoms, possibly by producing progestagenic symptoms
which the bodybuilder confuses as estrogenic, or by altering estrogen
metabolism, or by upregulating aromatase.

Compared to what bodybuilders expect of it, the drug is reasonably
mild when no aromatizing steroids are present. I consider its potency
approximately comparable to Dianabol. It is not unusual for a first
time user to do quite well on an oxymetholone-only cycle, but more
advanced users will want to stack with another steroid. Typical use is
50-150 mg/day, which should be divided into several doses per day.

Because

oxymetholone is
17-alkylated, it is stressful to the liver. It is better to limit use
to no more than 6 weeks or preferably four weeks before taking a break
of at least equal length. Many users feel that it is more effectively
used in the beginning parts of the cycle, rather than in the last few
weeks.