Finasteride, a reductase inhibitor, will not be effective in combating some of the androgenic side effects of oxymetholone. This is due to the fact that while oxymetholone does convert to dihydrotestosterone, this does not involve the 5 alpha reductase enzyme (2). Oxymetholone is a dihydrotestosterone based steroid. It differs only from dihydrotestosterone only due to the addition of a 2-hydroxymethylene group. This grouping can be removed metabolically which in turn would reduce the compound to 17 alpha-methyl dihydrotestosterone 1. It is this biotransformation that can explain, at least partially, the strong androgenic effect that oxymetholone has.
There is limited information available on the pharmacokinetics of oxymetholone.  It appears to be well-absorbed with oral administration .  Oxymetholone has very low affinity for human serum sex hormone-binding globulin (SHBG), less than 5% of that of testosterone and less than 1% of that of DHT.  The drug is metabolized in the liver by oxidation at the C2 position, reduction at the C3 position, hydroxylation at the C17 position, and conjugation .   The C2 hydroxymethylene group of oxymetholone can be cleaved to form mestanolone (17α-methyl-DHT), which may contribute to the effects of oxymetholone.  The elimination half-life of oxymetholone is unknown.  Oxymetholone and its metabolites are eliminated in the urine .  
What is a cycle Oxymetholone effective?
What amounts of Anadrol 50 should you use, what dosage Oxymetholone Will work best? It should be known that for most steroids, the more you take product, the more effective the cure and the results will be impressive. Anadrol is one of the few steroids where the more you take product, the more the efficiency curve tends to flatten out quickly. The recommended perfect gains relative to the degree of toxicity are around 50mg of Anadrol. You can go up to 100mgs of Anadrol, you will take even more mass, but it has been proven that taking 100mg of Anadrol per day is as effective as taking 150mg, so you have no interest in Exceed 100 mg per day.