All anabolic steroids express negative cardiovascular side effects, which include vascular reactivity (hardening of the blood vessels), increased blood pressure, increased hematocrit levels, and most impacting: the negative alteration of cholesterol values. Anabolic steroids have a tendency to temporarily reduce HDL (the good cholesterol), and many will also temporarily increase LDL (the bad cholesterol). This alteration can impact the risk the user has in developing cardiovascular disease, especially the longer the user remains on a cycle of anabolic steroids. Injectable anabolic steroids tend to be the least impacting, while oral anabolic steroids tend to be the worst (due to their route of administration and impact on the liver, which is essentially the cholesterol processing center for the human body). Parabolan, being an injectable anabolic steroid, possibly impacts cholesterol levels to a far lesser degree than oral anabolic steroids but at the same time impacts cholesterol levels negatively to a greater degree than most injectables due to the increased resistance to metabolism in the body. Cholesterol values tend to quickly return to normal once anabolic steroid use has ceased, and it is highly advised for the anabolic steroid user to engage in a clean diet alongside the supplementation of healthy omega-3 fats in order to maintain healthy levels of HDL cholesterol. The use of cardiovascular support supplements is also recommended.
It should be noted that in theory if one was to consistently suppress your natural estrogen levels for a long period of time, this would negatively impact your health, including your cholesterol. Due to the ability of Letrozole- to inhibit estrogen so much, this should definitely be a concern to most users. However the research that has focused on the relationship between use of letrozole and cholesterol levels is rather inconsistent in it's findings. Many studies have concluded that the compound is detrimental to both a user's HDL and LDL cholesterol levels, while other research has found no link. Obviously individuals are best served to monitor their cholesterol while using any compound via blood tests however barring that, letrozole should simply not be run for extended periods of time if at all possible. Doing so could cause serious medical complications.
Along with the issues related to blood lipids is the fact that many users complain that their libido is dramatically reduced when using the compound. This is related to the fact that estrogen is partly responsible for the regulation of an individual's sex drive. Since Letrozole- is so potent it can often drive estrogen levels too low and this inhibits a user's libido. To avoid this users can lower dosages, but some anecdotally report that even extremely low doses of the drug can cause problems. If this is the case a less potent compound such as exemestane or anastrozole may be a more appropriate option.
571. J. Mathieu, Proc. Intern. Symp. Drug Res. 1967, p 134. Chem. Inst. Can., Montreal, Canada.
572. Unique steroid congeners for receptor studies. Ojasoo, Raynaud. Cancer Research 38 (1978):4186-98.
573. Characterisation of the affinity of different anabolics and synthetic hormones to the human androgen receptor, human sex hormone binding globulin and to the bovine progestin receptor. Bauer, Meyer et al. Acta Pathol Microbiol Imunol Scand Suppl 108 (2000):838-46.
574. Unique steroid congeners for receptor studies. Ojasoo, Raynaud. Cancer Research 38 (1978):4186-98.
575. Disposition of 17 beta-trenbolone in humans. Spranger, Metzler. J Chromatogr 564 (1991):485-92.
576. Cholestasis induced by Parabolan successfully treated with the molecular adsorbent recirculating system. Anand JS et al. ASAIO 2006. JanFeb;52(1):117-8.