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.
Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
A 31-year-old man presenting with an 18-month history of sexual dysfunction resulting from severe adult-onset IHH (LH U/L, FSH U/L, T nmol/L). Initial therapy with 50 mg of clomiphene citrate (CC) three times a day for 7 days, with overnight LH pulse profiling and 9 am T levels evaluated at baseline and on completion. A 2-month washout period, followed by low-dose maintenance therapy (25-50 mg/d) for 4 months.
MAIN OUTCOME MEASURE(S):Baseline and stimulated T levels and LH pulsatility; effect on sexual function.
RESULT(S):Clomiphene therapy resulted in complete normalization of pulsatile gonadotropin secretion, serum T level, and sexual function. CONCLUSION(S):Isolated hypogonadotropic hypogonadism may result from an acquired defect of enhanced hypothalamic sensitivity to E-mediated negative feedback. Whereas direct T replacement therapy can further suppress endogenous gonadotropin secretion, treating IHH men with gonadotropins can stimulate endogenous T secretion and enhance fertility potential. On theoretical grounds, reversal of gonadotropin deficiency with CC might be expected to have a similar biological effect.