Letrozole once a week normalizes serum testosteron

Just some nice info about Letro.



Eur J Endocrinol. 2008 May;158(5):741-7. doi: 10.1530/EJE-07-0663.
Letrozole once a week normalizes serum testosterone in obesity-related male hypogonadism.
Loves S, Ruinemans-Koerts J, de Boer H.

Source
Department of Internal Medicine, Ziekenhuis Rijnstate, Wagnerlaan 55, 6800 TA Arnhem, The Netherlands.
Abstract

OBJECTIVE:
Isolated hypogonadotropic hypogonadism (IHH) is frequently observed in severely obese men, probably as a result of increased estradiol (E(2)) production and E(2)-mediated negative feedback on pituitary LH secretion. Aromatase inhibitors can reverse this process. This study evaluates whether letrozole once a week can normalize serum testosterone in severely obese men and maintain its long term effect.

DESIGN:
Open, uncontrolled 6-month pilot study in 12 severely obese men (body mass index>35.0 kg/m(2)) with obesity-related IHH and free testosterone levels <225 pmol/l, treated with 2.5 mg letrozole once a week for 6 months.

RESULTS:
Six weeks of treatment reduced total E(2) from 123+/-11 to 58+/-7 pmol/l (P<0.001, mean+/-s.e.m.), and increased serum LH from 4.4+/-0.6 to 11.1+/-1.5 U/l (P<0.001). Total testosterone rose from 5.9+/-0.5 to 19.6+/-1.4 nmol/l (P<0.001), and free testosterone from 163+/-13 to 604+/-50 pmol/l (P<0.001). Total testosterone rose to within the normal range in all subjects, whereas free testosterone rose to supraphysiological levels in 7 out of 12 men. The testosterone and E(2) levels were stable throughout the week and during the 6-month treatment period.

CONCLUSION:
Letrozole 2.5 mg once a week produced a sustained normalization of serum total testosterone in obese men with IHH. However, free testosterone frequently rose to supraphysiological levels. Therefore, a starting dose <2.5 mg once a week is recommended.

Here is another one:


Letrozole, the new anti-estrogenic T booster






Men who take 2.5 mg letrozole daily will notice that their testosterone levels double and the concentration of estradiol in their blood decreases by 45 percent. Urologists at the University of Mersin in Turkey write about this soon in Fertility & Sterility.




Letrozole


Aromatase
Letrozole [structural formula shown here] is the active ingredient in Nova Labs’ Femara. Letrozole inhibits the enzyme aromatase [structural formula also shown here], which converts testosterone analogues into estradiol.

In men with relatively high amounts of estradiol and low amounts of testosterone in their blood, the testes theoretically work less hard. So the researchers did an experiment with 27 infertile men. The subjects were given a pill every day for six months that contained 2.5 mg letrozole. More than half of the subjects produced virtually no sperm cells.

The table below shows that the treatment increased the subjects’ testosterone level and lowered their estradiol level. Both quantity and quality of sperm cells increased.







No serious side effects were observed either. A few men developed mild headaches, but these were not serious enough for them to withdraw from the trial.

In a Dutch study with overweight men, the subjects’ testosterone level quadrupled when they took a weekly pill containing 2.5 mg letrozole. In a Canadian case study, a daily 2.5 mg dose doubled the subjects’ testosterone levels. [Fertil Steril. 2009 Aug;92(2):829.e1-2.]

Although all the studies mentioned here used men who had some kind of problem, we at Ergo-log, unhindered by scientific insight, dare to make the following pronouncement: athletes who want to increase their testosterone production are better off taking letrozole once every 5-7 days rather than daily.

Source:
Fertil Steril. 2010 Oct 8. [Epub ahead of print].
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Anything that lowers your estrogen will raise testosterone levels. So any AI or SERM. Unfortunately you can't stay on them indefinitely because it's not healthy, and when you stop taking them your levels return to what they were before.

I don't want people to get the wrong idea.

Muscleaddict wrote: Anything that lowers your estrogen will raise testosterone levels. So any AI or SERM. Unfortunately you can't stay on them indefinitely because it's not healthy, and when you stop taking them your levels return to what they were before.

I don't want people to get the wrong idea.

Yes i should probably get a study on estro rebound as well!

No i just thought its interesting. Id rather use Exemestane or a proper cycle for that matter.

Some awesome research coming through. I just dig it when guys can produce evidenced based articles to make a point.


Good work.

Regards