Letrozole (Femara) and Arimidex are the two most popular of the three major Aromatase Inhibitors, with Letrozole being the second most popular.
Letrozole has demonstrated remarkable efficiency in reducing estrogen compared to the other two primary Aromatase Inhibitors.
When compared to Arimidex, Letrozole was found to be 10-20 times more potent, and while its dosage is the same as Aromasin, it works through a different pathway, making it highly effective on its own [1].
However, the context is somewhat different from the medical and clinical use of Letrozole or Aromatase Inhibitors by athletes or bodybuilders using anabolic steroids.
This is why every anabolic steroid user is most curious to learn about the proper Letrozole dosage for estrogen control, how to utilize Letrozole dosing, and the various ways Letrozole dosing can be used.
First, it must be understood that Letrozole is an Aromatase Inhibitor and is applied in various ways regarding estrogen control.
As an Aromatase Inhibitor, it possesses the ability to literally control all potential estrogenic side effects that an anabolic steroid user seeks to avoid or eliminate.
The standard protocol (or general rule) for all Aromatase Inhibitor use should be as follows:
The use of Aromatase Inhibitors should be avoided unless absolutely necessary.
If an Aromatase Inhibitor must be used, it should be used only when absolutely necessary, for the purpose of estrogen control rather than estrogen elimination, and at the lowest possible dose.
This is extremely important and must be remembered by any reader reviewing the use of Aromatase Inhibitors.
The important fact is that Aromatase Inhibitors, whether the three primary AIs (Arimidex, Aromasin, Letrozole) or any others, can negatively impact the body if used unnecessarily or if the Letrozole dosage is excessively high.
It must be remembered that the reason for using an Aromatase Inhibitor is always for estrogen control, not elimination, because completely reducing all estrogen levels in the body can and will have detrimental effects on the human body.
This will be covered in detail in the side effects section of this profile, but generally speaking, it can be explained that these compounds (Aromatase Inhibitors) rob the body of a very important hormone (estrogen) that is crucial for various essential bodily functions at normal physiological levels.
Medical Letrozole Dosage
Letro is FDA approved as an adjunct treatment for postmenopausal women with breast cancer who have failed primary treatment (Nolvadex, etc.).
It is also approved as an extended treatment for postmenopausal women with breast cancer after 5 years of Nolvadex administration.
Letrozole is also approved for the treatment of postmenopausal women with breast cancer who show symptoms of breast cancer with unknown estrogen receptor status.
This is a breast cancer condition where diagnosis cannot determine if estrogen is the cause or if the breast cancer is exacerbated by estrogen.
Finally, it is also approved for the treatment of postmenopausal women with breast cancer for whom all other anti-estrogen compounds (SERMs and all other AIs) have been ineffective.
Letrozole is often attempted as a last resort and final treatment for breast cancer patients after all other treatments have failed.
The Letrozole dosage for all cases of breast cancer treatment is 2.5mg daily.
Letrozole Dosage During Anabolic Steroid Use
Specifically, Letrozole cannot be categorized into the three common user tiers (beginner, intermediate, and advanced) as is typically described and listed in the general profiles of other compounds and drugs.
This is because Letrozole is not specifically used for performance enhancement purposes; rather, it is an ancillary drug used to prevent or mitigate various estrogen-related side effects when using aromatizable anabolic steroids.
In some cases, Letrozole may also be used to increase endogenous secretion in men, and this compound can be used as an ancillary drug during the PCT (Post Cycle Therapy) phase after an anabolic steroid cycle ends, but its use for this purpose alone is not common and is unlikely to show noticeable performance-enhancing effects.
The use of Letrozole as an endogenous stimulant will be covered in detail shortly.
For the purpose of estrogen control during a cycle:
Letrozole is the most effective Aromatase Inhibitor used during cycles involving aromatizable androgens (anabolic steroids that have an affinity for binding with the aromatase enzyme and aromatizing into estrogen) to lower circulating estrogen levels in the body.
This was explained earlier in the introduction.
The Letrozole dosage for this purpose is very broad, and how much Letrozole is needed (and how often) depends heavily on the dosage of the aromatizable anabolic steroid being used, the individual’s sensitivity to Aromatase Inhibitors, and the aromatization rate of the anabolic steroid used.
Therefore, the general dosage for Letrozole is approximately 1.25mg to 2.5mg daily.
There is significant room for adjustment in Letrozole dosage and user preference, as each individual must slowly adjust the dosage based on how their body responds.
This is especially true with Letrozole, as it is the most potent and powerful AI of the three.
For many anabolic steroid users, even 1.25mg daily is too much, and the recommended dosage is often 1.25mg every other day, and considering Letrozole’s half-life of 2-4 days, it is often the case that even less is used.
This Letrozole dosage can be easily adjusted if the user feels it is not effective enough or if estrogen levels are dropping too much.
It must always be remembered that the purpose of using an Aromatase Inhibitor is not to completely reduce or eliminate estrogen levels to cause problems for the body, but to regulate estrogen levels back to normal physiological ranges.
For the purpose of reversing/eliminating gynecomastia:
Clinical data on rats and anecdotal evidence have demonstrated that Letrozole can indeed reverse and eliminate the progression of gynecomastia.
This is one of the unique effects specific to Letrozole.
While other Aromatase Inhibitors may exhibit this effect, once gynecomastia has progressed beyond a certain point, it becomes irreversible and must be removed surgically.
Letrozole does not have the ability to remove fully developed gynecomastia, but it has demonstrated the potential to reverse developing gynecomastia, far surpassing the reversible capabilities of Aromasin (Exemestane) or Arimidex (Anastrozole).
Particularly, studies on mice have shown that receptor overexpression (induced by estrogen) that causes breast changes is destroyed even with low doses of Letrozole [2].
Although these studies were performed on mice, there are numerous anecdotal reports of Letrozole, often in conjunction with a SERM (such as Nolvadex), effectively reducing and eliminating developing gynecomastia in patients where all other treatment attempts had failed.
While reversal of gynecomastia is not guaranteed (especially as it depends on the circumstances), it is worth a try, particularly if the gynecomastia has occurred recently (the sooner treatment begins after gynecomastia onset, the better).
Female Letrozole Dosage
Female anabolic steroid users have little reason to worry about elevated estrogen levels; however, in the case of competitive bodybuilders who need to eliminate estrogen-related water retention that causes unwanted bloating, they may need to use an Aromatase Inhibitor like Letrozole (Femara).
However, due to the potent effects of Letrozole, it is recommended that females try one of the other two primary Aromatase Inhibitors first before using Letrozole.
This is because it has been medically proven that Aromatase Inhibitors actually have a much greater impact on estrogen reduction in females than in males.
It is important to remember that medically, Letrozole is approved for use only in postmenopausal women and premenopausal women, whose hormone levels are very different.
Even among postmenopausal breast cancer patients, Letrozole is used as the absolute last line of defense against breast cancer after all other treatments and medications have failed.
According to medical data, since Aromatase Inhibitors are much more effective in females than in males (depending on the AI used), a Letrozole dosage of 1.25mg every other day or every two days is often sufficient, and in reality, too high a dose is often administered, in which case the individual may feel the need to adjust to a lower dose or less frequent administration.
Letrozole Dosage for Increasing Endogenous Testosterone Secretion and PCT (Post Cycle Therapy)
It was mentioned earlier that Letrozole has the potential to increase endogenous secretion in men.
This occurs through the negative feedback loop of the Hypothalamic-Pituitary-Testicular Axis (HPTA), where excessive estrogen in men has been found to suppress, and indeed does suppress, endogenous production, leading to hypogonadism [3].
Specifically, numerous studies have proven Letrozole’s efficacy in increasing levels through estrogen reduction.
One study concluded that administration of Letrozole to elderly men with sexual dysfunction due to impaired endogenous androgen production resulted in levels returning to normal physiological ranges and restoration of sexual function [4].
This study found that LH (Luteinizing Hormone) and FSH (Follicle-Stimulating Hormone) increased, while SHBG (Sex Hormone-Binding Globulin) decreased.
LH and FSH are the two key gonadotropin hormones that signal the testes to begin production, and SHBG is a protein that binds to androgens, rendering them inactive (much in the same way an Aromatase Inhibitor binds to the aromatase enzyme and deactivates it).
In the same study, Letrozole was so effective at reducing estrogen in men that the subjects’ estrogen levels were actually undetectable.
Based on the data provided, one can easily conclude that Letrozole would be effective for the necessary increase for several weeks after discontinuing anabolic steroid use.
There is one problem with adding Letrozole to a PCT program that includes the use of SERMs like Nolvadex and Clomid, which are known to be absolutely essential components of a PCT program.
This same issue is apparent with Arimidex but does not occur with Aromasin (Exemestane).
The problem is that Letrozole and Nolvadex (Arimidex and Nolvadex) directly cancel each other out.
One study found that when Letrozole and Nolvadex are used together, Nolvadex reduces the plasma concentrations of Letrozole (and Arimidex, another commonly used Aromatase Inhibitor) [5].
The conclusion is that using Letrozole and Nolvadex together is a very bad idea.
Therefore, the use of Letrozole as a PCT component is very limited when used alongside Nolvadex.
It might be more beneficial to use it in conjunction with HCG instead, but this presents the problem of lacking the essential component of SERMs for the purpose of endogenous stimulation.
Therefore, a better Aromatase Inhibitor for PCT instead of Arimidex would be Aromasin (Exemestane), because unlike Letrozole, Aromasin has been proven by research not to have its effects canceled out or reduced by Nolvadex [6].
Proper Letrozole Dosage and Timing of Administration
There is nothing special to consider when taking Letrozole; it can be taken at any time of day (morning, evening, before, with, or after meals).
One important point regarding Letrozole administration is that while its half-life is approximately 2-4 days [7], it actually takes 60 days for plasma blood levels to reach optimal peak levels.
Letrozole requires the longest time among the three primary Aromatase Inhibitors to reach optimal peak plasma blood levels (in contrast, Arimidex and Aromasin take 7 days to reach optimal peak plasma concentrations).
Expected Effects and Results from Letrozole Use
Since Letrozole is the most effective Aromatase Inhibitor at reducing estrogen levels to undetectable levels, users must be cautious not to let their estrogen levels drop too low to be considered healthy.
With lowered estrogen levels, one’s physique may appear tighter and more ‘shredded’ due to the loss of water retention provided by estrogen.
This results in little to no subcutaneous water, making muscles appear more prominent.
One exception to the problem of completely eliminating estrogen is for competitive bodybuilders on the day of competition, who need to eliminate almost all water retention.
In such situations, Letrozole may be the best Aromatase Inhibitor over all others for a competitor to use at maximum dosage a few days out from a show, for the physique changes mentioned earlier.
The near-total reduction of estrogen should not be maintained for more than 48 hours for health reasons.
Medical References
[1] Pharmacology and pharmacokinetics of the newer generation aromatase inhibitors. Buzdar AU. 2003 Jan;9(1 Pt 2):468S-72S.
[2] Aromatase overexpression transgenic mice model: cell type specific expression and use of letrozole to ablate mammary hyperplasia without affecting normal physiology. Mandava U, Kirma N, Tekmal RR. 2001 Dec;79(1-5):27-34.
[3] “The Dangers of Excessive Estrogen in the Aging Male”. Faloon, William. Life Extension Magazine, November 2008.
[4] Aromatase inhibition, testosterone, and seizures. Harden C, Mac Lusky NJ. Epilepsy Behav. 2004 Apr;5(2):260-3.
[5] Comparative clinical pharmacology and pharmacokinetic interactions of aromatase inhibitors. 2001 Dec;79(1-5):85-91, Boeddinghaus IM, Dowsett M. J Steroid Biochem Mol Biol.
[6] Inhibitory effects of the combination of 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. 2003 Jan;9(1 Pt 2):468S-72S.
