Hunty, I am not that knowledgable on spironolactone. I believe it does increase estrogen, otherwise you would not experience regrowth from it. If it didn't increase E, then how can it lead to feminisation or other estrogenic effects?
https://www.ncbi.nlm.nih.gov/pubmed/747893
Within this study (at 300mg/day for more than 40 weeks), it states:
'In the high-dosage group, serum oestrone maintained high levels from the beginning of this study, and serum oestradiol concentrations increased with the development of gynaecomastia.'
'Thus, long-term spironolactone treatment increased the serum levels of oestrone and oestradiol in hypertensive men followed by the development of gynaecomastia. The elevation in circulating oestrogens could well explain the oestrogenic side-effects of spironolactone treatment.'
Furthermore (at 75mg to 150mg for 12 weeks), it states:
'In the conventional-dosage group, serum oestrone concentrations significantly increased (P less than 0.01) at 12 weeks, serum oestradiol concentrations gradually increased throughout the study period, however, the increments were not statistically significant (P less than 0.2).'