Aromatase inhibitors. (AI's) An aromatase inhibitor (AI) is a drug or natural substance that binds to the enzyme aromatase either temporarily or permanently. This then prevents the enzyme from performing its primary function. These days aromatase inhibitors both synthetic or natural in origin are widespread in use in the bodybuilding and physique drug/supplement arsenal but what are AI's? How do they work and what are their potential side effects. Most importantly, would you personally want to use an AI and why. Aromatase inhibitors were originally designed for use in female breast cancer patients. Those whos cancers were estrogen driven will generally see some improvement in prognosis when estrogen levels are lowered. Often an AI will be used alone or in concert with other drugs such as SERMS. More on SERMs in another article. In the last decade or so alot of natural AI's have been discovered and released as dietary supplements not for female cancer patients but for male athletes and bodybuilder but why? Aromatase is the enzyme that converts testosterone to estrogen. In males estrogen is made primarily through this conversion. Testosterone> aromatase= estrogen. So by binding to the enzyme aromatase, AI's prevent testosterone from becoming estrogen. This lowers estrogen and raises testosterone levels. Testosterone rises partially because less is being converted but also because estrogen is made from testosterone. The brain, sensing estrogen is low will continue to send the signal LH(leutinizing hormone) to the testes so more testosterone can be made to be converted to estrogen, but, this conversion is being blocked so test levels continue to rise. This is of course exceptionally good for bodybuilders and physique athletes for several reasons. Firstly testosterone is muscle building and fat burning and contributes to strength, libido and so many other things male but, also low estrogen leaves us looking hard and dry while contributing even more to fat loss. For those using aromatizing steroids, prohormones and supplements AI's are crucial for managing estrogen levels but they can be used alone or in concert just for their test boosting and estro lowering benefits. There are 2 types of AI's. Suicidal, which binds to aromatase permanently and Non suicidal which binds only temporarily. The Non suicidal can, upon cessation of administration cause an abnormal rise in estrogen levels so some choose to taper off. Extremely low estrogen levels can cause dry, creaking, painful joints but this is not always the case. Extremely low estrogen can reduce libido and cause abnormally high cholesterol levels. These issues are generally only seen at high doses used for long periods. Cancer patients may take excessively high doses many times higher than we would use and for years at a time. Short term, supplemental doses generally have few side effects. Currently the strongest non prescription AI is found in Letrone. Containing atractylodes macrocephala, a plant with multiple exceptionally strong AI's Letrone is not only effective as an AI but also raises Growth hormone, IGF-1 and raises T3, T4 and cAMP which all help increase fat burning. Letrone is an exceptional natural anabolic on its own but works even better when stacked with Follidrone 2.0 or any of our other products.