With Boldenon in moderate doses aromatisation is usually not a problem to worry about. But it does aromatise a little so if you are sensitive or uses Boldenon in high doses there is still a reason to look out. This means that the risk of side effects like gynocomastia and water retention is small. The small aromatisation that does occur is positive for the glucose utilization (bringing back glycogen in the cell after a hard workout) and increases your natural growth hormone release. The main advantage is that oestrogen upgrades the androgen receptors giving an anabolic effect. Boldenon is not so toxic for the liver and the DHT conversion is also low. Acne and high blood pressure problems are also rare, this steroid is in all fairly safe to use and very much recommended.
Having said this, Masteron when initially produced pharmacologically, was seen by the FDA as a relatively safe medicine, even at high dosages. Dosages in excess of 150mg per day (that's over 1000mg per week) were considered as safe limits by the FDA (bear in mind most other AAS used by athletes are used in levels that exceed FDA safe limits). This is good news to the user, however do not misinterpret this information as a reason to use excessive doses of Masteron as in reality anything above 600mg per week is not going to give any more benefit than 500-600mg per week would give, thus excessive use would be a waste of money and injections.