I've tried plenty of AI chemical research companies in the past. None compare to my first dose of .5ml Aromasin from Pure Essence. Was feeling the dreadful high estrogen effects from HCG like I normally do and decided to try my first dose of the Aromasin. Let's just say I overkilled my estrogen to the point of waking up the next morning with crazy joint pain, feeling very tired, wow my estrogen plummeted. I ended up taking 50mg Zinc before bed the same night, these guys are the most potent out there for any AI I've ever tried. I've had to go with Letro from other chemical research companies and even then I never got my estrogen this low before. I bet this Aromasin even registers higher on the equivalent dosing of the prescription variety. Extremely pleased, loving the veiny vascular look the AI gave me as well. Can't wait to stock up on their SARMS, I'll have my pocket book ready for Black Friday!!!