Letrozole Dosage


Letrozole (Femara) and Arimidex are the two most popular aromatase inhibitors of the 3 major AIs, with Letrozole being the second most popular. Letrozole has demonstrated some very incredible efficiency in the reduction of Estrogen, more so than the other two major aromatase inhibitors. In comparison with the Arimidex, Letrozole has been found to be 10 – 20 times the strength of Arimidex, and although Letrozole doses are equally as effective as Aromasin, it operates through a different pathway in order to be highly effective in its own right[1]. However, the context that an anabolic steroid using athlete or bodybuilder is slightly different from the medical and clinical application of Letrozole or any aromatase inhibitor, and this is what any anabolic steroid user is most concerned with: the proper Letrozole doses for Estrogen control, how to utilize Letrozole doses, and the different manners in which Letrozole doses can be used.

It must first be understood that Letrozole is an aromatase inhibitor, with a wide variety of application in terms of Estrogen control. As an aromatase inhibitor, it holds the ability to exert control over literally all of the potential Estrogenic side effects that anabolic steroid users attempt to avoid or eliminate. The standard protocol (or general rule) for the use of all aromatase inhibitors should be the following:

Attempt to avoid the use of aromatase inhibitors at all costs unless absolutely necessary. If the use of an aromatase inhibitor is necessary, utilize it only when required, and attempt the lowest possible dose for the purpose of Estrogen control rather than Estrogen elimination.

This is extremely important and must be remembered by all readers investigating the use of aromatase inhibitors. The fact of the matter is that the use of aromatase inhibitors, whether it be the three primary AIs (Arimidex, Aromasin, and Letrozole) or any others, will exert negative effects on the body if utilized when they are either unneeded, or when they are utilized too much at Letrozole doses that are too high.

Remember that the reason for the use of an aromatase inhibitor should at all times be for the purpose of Estrgen control rather than Estrogen elimination, as the complete and total reduction of all Estrogen levels in the body can and does result in deleterious effects on the human body. This will be further explained in the side effects portion of this profile, but a general description is that these compounds (aromatase inhibitors) deprive the body of a very important hormone (Estrogen) that is important for various essential bodily functions at normal physiological levels.

Medical Letrozole Dosage

Letro is approved by the FDA for the treatment of post-menopausal female breast cancer patients as an adjunctive treatment when first-line treatments (such as Nolvadex) have failed to work. It is also approved for the extended treatment for post-menopausal female breast cancer patients after 5 years of Nolvadex administration. Letrozole is also approved for the treatment of post-menopausal female breast cancer patients that are exhibiting symptoms of Estrogen receptor unknown breast cancer. This is a breast cancer condition in which the diagnosis indicates that it is unknown as to whether or not Estrogen is the culprit, or whether or not the breast cancer is aggravated by Estrogen. Finally, it is also approved for the treatment of post-menopausal female breast cancer patients for whom all other anti-Estrogen compounds have not worked (this includes SERMs and all other AIs). Letrozole is often the last-resort and final treatment attempt for breast cancer patients when all else has failed.

The Letrozole dosage for breast cancer treatment in all cases are that of 2.5mg daily.

Letrozole Dosage During Anabolic Steroid Use

Letrozole in particular cannot be categorized into the three tiers of users (beginner, intermediate, and advanced) as normally outlined and listed in common profiles of the different compounds and drugs. This is due to the fact that Letrozole is an ancillary drug not particularly used for the purpose of performance enhancement, but instead is utilized to combat or mitigate various Estrogen-related side effects when aromatizable anabolic steroids are utilized.

In some instances, Letrozole doses might possibly also be utilized to increase the endogenous secretion of Testosterone in men, which allows this compound to be utilized as an ancillary medication during PCT (Post Cycle Therapy) phases following the end of an anabolic steroid cycle, but its use on its own for this purpose is not very common and is unlikely to produce noticeable performance enhancing effects. Letrozole’s use as an endogenous Testosterone stimulating agent will be further covered in detail shortly.

For the purpose of Estrogen control during a cycle: Letrozole is the most effective aromatase inhibitor utilized to reduce levels of circulating Estrogen in the body during a cycle involving the use of aromatizable androgens (anabolic steroids that have an affinity to bind to the aromatase enzyme and undergo aromatization into Estrogen). This has been outlined previously in the introduction. Letrozole doses for this purpose cover a very wide range, and how much Letrozole is required (and how often) is also largely dependent on the doses of aromatizable anabolic steroids used, the individual’s sensitivity to aromatase inhibitors, and the rate of aromatization of the anabolic steroids used. With this being said, the general range of Letrozole doses are approximately 1.25mg – 2.5mg daily. There does exist a very large margin for adjustment and user preference when it comes to Letrozole dosages, as each individual should slowly adjust their dose depending on how they feel the body is responding. This is especially so for Letrozole, which is the most powerful and potent AI of the three. Even 1.25mg daily is too much for many anabolic steroid users, and often times the recommended dose is actually 1.25mg every other day, and often can be even less frequent especially considering the half-life of Letrozole is that of 2 – 4 days. These Letrozole doses can easily be adjusted if the user feels it is not working well enough, or if it is reducing Estrogen levels too much.


Always remember that the idea with the use of aromatase inhibitors is to control Estrogen levels and bring them back to normal physiological levels as opposed to the complete reduction and/or elimination of them, which will cause problems in the body.

For the purpose of gynecomastia reversal/elimination: It has been a proven fact both in clinical data involving mice, as well as anecdotal evidence that Letrozole is indeed capable of reversing and eliminating gynecomastia progression. This is one particular effect that is slightly more unique to Letrozole itself. It should be known that other aromatase inhibitors can exhibit this effect as well, but if gynecomastia has progressed beyond a certain point, it will be irreversible and removal must be done through surgery. Letrozole does not hold the ability to remove fully developed gynecomastia, but has demonstrated the ability to potentially reverse gynecomastia at development stages far beyond the reversal capabilities of Aromasin (Exemestane) or Arimidex (Anastrozole). One particular study on mice demonstrated that receptor overexpression (caused by Estrogen) that induced mammary gland changes were destroyed with even low doses of Letrozole[2]. Although these studies were performed on mice, there are plenty of anecdotal reports of bodybuilders developing gynecomastia who have utilized Letrozole in combination with a SERM (such as Nolvadex) that have effectively reduced and eliminated progressing gynecomastia where all other treatment attempts have failed. Although gynecomastia reversal is not guaranteed (especially depending on circumstances), it is worth a try for individuals who especially have recently developed gynecomastia (the sooner the treatment following gynecomastia development, the better).

Female Letrozole Dosage

Female anabolic steroid users seldom need to worry about rising Estrogen levels, but for those that are competitive bodybuilders that must eliminate the water retention associated with Estrogen that causes the unwanted bloating, the use of an aromatase inhibitor such as Letrozole (Femara) might be necessary. However, because of the immense strength of Letrozole, it is recommended that females attempt the use of one of the other two major aromatase inhibitors prior to resorting to Letrozole use. This is because it has been demonstrated medically that aromatase inhibitors in fact do impact Estrogen reduction in females far greater than that of males.

It is important to remember that medically, Letrozole is approved for use in post-menopausal females only, who possess a very different shift in hormone levels compared to pre-menopausal females. Even among post-menopausal female breast cancer patients, Letrozole is utilized as the absolute last resort last-line of defense against breast cancers after all other treatments and drugs have failed. Because medical data has suggested that aromatase inhibitors are far more effective in females than males (depending on the aromatase inhibitor in question used), Letrozole doses of 1.25mg every other day or once every two days should suffice and in fact often times become too much, in which case the individual might feel the need to adjust to either a lower dose or a lesser frequency of administration.

Letrozole Dosage for Increased Endogenous Testosterone Secretion and PCT (Post Cycle Therapy)

It has been previously mentioned that Letrozole holds the potential to raise the endogenous production of Testosterone levels in men. This is through the negative feedback loop of the HPTA (Hypothalamic Pituitary Testicular Axis), whereby it has been found that excess Estrogen in men can and does suppress the output of endogenous Testosterone, leading to hypogonadism[3]. Letrozole in particular in many studies has demonstrated to hold the capability to raise Testosterone levels through the reduction of Estrogen. One particular study evaluated an elderly male exhibiting sexual dysfunction issues resultant of low endogenous androgen production that was administrated with Letrozole doses, and the study concluded that Testosterone levels were restored normal physiological levels and sexual function was restored[4]. In this study, LH (Luteinizing Hormone) and FSH (Follicle Stimulating Hormone) had increased, while SHBG (Sex Hormone Binding Globulin) had decreased. LH and FSH are the two important gonadotropins that signal the testes to begin production of Testosterone, while SHBG is a protein that binds to androgens and renders them inactive (in much the same way aromatase inhibitors will bind to the aromatase enzyme and render it inactive). The same study had determined that Letrozole was so effective at Estrogen reduction in men that the test subject’s Estrogen levels were in fact undetectable.

One can easily conclude, based on the data provided, that Letrozole would be an effective addition to the necessary increases in Testosterone required during the post-cycle weeks following cessation of anabolic steroid use. There is one issue with the addition of Letrozole in a PCT program that includes the use of SERMs such as Nolvadex and Clomid, which are known as absolutely essential components to a PCT program. This same problem is evident in Arimidex, but not in Aromasin (Exemestane). The problem is that Letrozole and Nolvadex (as well as Arimidex and Nolvadex) both directly counteract one another. One study has demonstrated that when Letrozole is utilized with Nolvadex, Nolvadex will decrease blood plasma concentration of Letrozole (as well as Arimidex, another commonly used aromatase inhibitor)[5].

The conclusion here is that the use of Letrozole and Nolvadex together is a very bad idea. Therefore, Letrozole’s use as a PCT component is very limited if used in conjunction with Nolvadex. Instead, its use with HCG might be more beneficial, but this also presents the problem of the essential component of a SERM for the purpose of endogenous Testosterone stimulation being absent. Therefore, a better aromatase inhibitor choice for PCT instead of Arimidex would be Aromasin (Exemestane), because unlike Letrozole, Aromasin has it has not been demonstrated have its effectiveness eliminated or reduced by Nolvadex as shown in studies[6].

Proper Administration and Timing of Letrozole Dosages

There are no special considerations with administration of Letrozole doses, and it can be taken at any time of the day (morning, night time, before, during, or after meals).

One important note to make with Letrozole doses is that it in fact takes 60 days before blood plasma levels of Letrozole have reached its optimal peak level, even though its half-life is approximately 2 – 4 days[7]. Letrozole possesses the longest required window of time for blood plasma levels to reach optimal peak out of all three major aromatase inhibitors (conversely, Arimidex and Aromasin require 7 days in order for optimal peak blood plasma levels to be reached).

Expectations and Results from Letrozole Dosages

Because Letrozole is by far the most effective aromatase inhibitor with the ability to reduce Estrogen levels to undetectable levels, users must be cautious to ensure that these Estrogen levels do not plummet too low to be considered healthy. As Estrogen levels decline, the physique may take on more of a harder ‘grainier’ and ‘ripped’ look due to the loss of water retention provided by Estrogen. This results in very little to no subcutaneous fluid, which will present the underlying musculature more prominently. The one exception to the issue of complete Estrogen elimination is in competitive bodybuilders that require almost total elimination of water retention on the competition day. In such a situation, Letrozole might possibly be the best aromatase inhibitor to use above all other AIs at a full dose utilized by a competitive athlete only days leading up to a competition for the physique altering reasons previously stated. Near-total reduction of Estrogen should not be maintained for more than a 48 hour period for health reasons.



Medical References:


[1] Pharmacology and pharmacokinetics of the newer generation aromatase inhibitors. Buzdar AU. Clin Cancer Res. 2003 Jan;9(1 Pt 2):468S-72S.

[2] Aromatase overexpression transgenic mice model: cell type specific expression and use of letrozole to abrogate mammary hyperplasia without affecting normal physiology. Mandava U, Kirma N, Tekmal RR. J Steroid Biochem Mol Biol. 2001 Dec;79(1-5):27-34.

[3] “Dangers of Excess Estrogen In the Aging Male”. Faloon, William. Life Extension Magazine, November 2008.

[4] Aromatase inhibition, testosterone, and seizures. Harden C, MacLusky NJ. Epilepsy Behav. 2004 Apr;5(2):260-3.

[5] Comparative clinical pharmacology and pharmacokinetic interactions of aromatase inhibitors. Boeddinghaus IM, Dowsett M. J Steroid Biochem Mol Biol. 2001 Dec;79(1-5):85-91.

[6] Inhibitory effect of combined treatment with the aromatase inhibitor exemestane and tamoxifen on DMBA-induced mammary tumors in rats.

[7] Pharmacology and pharmacokinetics of the newer generation aromatase inhibitors. Buzdar AU. Clin Cancer Res. 2003 Jan;9(1 Pt 2):468S-72S.