Anavar...
The main reasons for the wide-spread use of oxandrolone in sports is because it is very appealing to female athletes as well as male athletes. It causes little or no virilization properties, demonstrated by its medical uses to treat women. This is rather surprising since oxandrolone does not aromatize either. It's the only steroid that is both safe and convenient without producing excess estrogen.
Oxandrolone also has little effect on the body's own natural hormone production. The negative feedback was found to be very minor, meaning that during short term use no suppression of Gonadotropin releasing hormone (GnRH, start of natural testosterone production) was noted. This meant that whatever gains made, as little as they may have been, were very easily maintained post-cycle. So there was also no use for products like Clomid or Nolvadex in conjunction with oxandrolone consumption. The easy to maintain low gains would indicate a low binding to the androgen receptor.
Primo...
Methenolone however, is a DHT-based steroid (actually, DHB or dihydroboldenone, the 5-alpha reduced of the milder boldenon). Meaning when it interacts with the aromatase enzyme it does not form estrogens at all.
Primo can cause hairloss then... and if I had hairloss on JW.. I would more then likely have it on primo.