Jesu! Wikipedia has a page for everything!
"Although commonly compared to nandrolone, boldenone lacks progesterone receptor interaction and all the associated progestinic side effects. Boldenone can, however, produce mild androgenic side effects. Oily skin, acne, increased aggression and hair loss are all possible with this compound but rare. Boldenone does reduce to a more potent androgen dihydroboldenone via the 5alpha-reductase enzyme (analogus to the conversion of testosterone to dihydrotestosterone DHT), however its affinity for this interaction in the human body is low to nonexistent. Supression of the HPTA, water retention, possible increase in acne and possible conversion to estrogen , high blood pressure are all side effects associated with Boldenone. Boldenone is also known to cause anxiety and flu like symtoms which manifest themselves most acutely in short ester versions like: acetate, and propionate (almost unuseable), but which are also present in the enanthate, cypionate, and undecyclenate forms."
