The common side effects of oxymetholone include depression, lethargy, headache, swelling, rapid weight gain, priapism , changes in skin color, urination problems, nausea , vomiting , stomach pain (if taken on an empty stomach), loss of appetite, jaundice , breast swelling in men, feeling restless or excited, insomnia , and diarrhea .  In women, side effects also include acne , changes in menstrual periods , deepened voice, hair growth on the chin or chest, male pattern baldness , enlarged clitoris , and changes in sex drive .  Because of its 17α-alkylated structure, oxymetholone is highly hepatotoxic . Long term use of the drug can cause a variety of serious ailments, including hepatitis , liver cancer , and cirrhosis ; therefore periodic liver function tests are recommended for those taking oxymetholone. 
As for winny instead of proviron, for the most part proviron was always cheaper than winstrol, plus it is a great androgen - so that really helps with the quality look/dry look when low enough bodyfat.
Saying that, it does seem that they are pretty interchangeable.. i cant think of a good reason to use proviron over winstrol IF winstrol is as powerful a SHBG binding steroid as thought.
Masteron in most cases isnt much more than proviron, and is dosed at the same dosage.. so that could be used for its extra anabolism too... fuck it, throw them all in the mix!
Hi Sara I am carlo, regarding steroids I was always taking depo cyp testosterone 10ml week , sum tyms stop taking for 4 weeks,on an of ,sex driver was always gud,, but after dat I quit for gud for week, but as I am gyming I started taking testo blast zma Sa supplements an creatine hcl e amino acid 6000, after3 days taking dos supplements I am experiencing Low libido, but wen I play with my cook dase erect but tek long,even I stopped taking dos supplements for 4 days stl having sem problem . Must I get hcg to kick start natural testerone?