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.
Azelaic acid is used to treat mild to moderate acne, both comedonal acne and inflammatory acne.   It belongs to a class of medication called dicarboxylic acids . It works by killing acne bacteria that infect skin pores. It also decreases the production of keratin, which is a natural substance that promotes the growth of acne bacteria.  Azelaic acid is also used as a topical gel treatment for rosacea , due to its ability to reduce inflammation.  It clears the bumps and swelling caused by rosacea. The mechanism of action is thought to be through the inhibition of hyperactive protease activity that converts cathelicidin into the antimicrobial skin peptide LL-37.  Azelaic acid has been used for treatment of skin pigmentation including melasma and postinflammatory hyperpigmentation , particularly in those with darker skin types. It has been recommended as an alternative to hydroquinone .  As a tyrosinase inhibitor, azelaic acid reduces synthesis of melanin .