Letrozole~femara

[heavyiron]

Femara® (letrozole)


Quick overview:

Active Life: 2-4 days
Drug Class: Aromatase inhibitor (Oral)
Average Dose: 0.5 - 2.5 mg/day
Acne: Yes
Water Retention: No
High Blood Pressure: May reduce bp when using aronatizable steroids
Liver Toxic: Yes, dose dependant
Decrease HPTA function: No

Femara®(generic name is letrozole) is a new drug developed for the treatment of advanced breast cancer in women. Femara is the second in a new class of third-generation selective oral aromatase inhibitors.. It acts by blocking the enzyme aromatase, subsequently blocking the production of estrogen. Since many forms of breast cancer cells are stimulated by estrogen, it is hoped that by reducing amounts of estrogen in the body the progression of such a disease can be halted. This is the basic premise behind Nolvadex, except this drug blocks the action and not production of estrogen. The effects of Femara can be quite dramatic to say the least. A daily dose of one tablet (2.5 mg) can produce estrogen suppression greater than 80 % in treated patients. With the powerful effect this drug has on hormone levels, it is only to be used (clinically) by post-menopausal women whose disease has progressed following treatment with Nolvadex. Side effects like hot flushes and hair thinning can be present, and would no doubt be much more severe in pre-menopausal patients.

For the steroid using male athlete, Femara shows great potential. Up to this point, drugs like Nolvadex and Proviron have been our weapons against excess estrogen. These drugs, especially in combination, do prove quite effective. But Femara appears able to do the job much more efficiently, and with less hassle. Its use is only now catching on, but early reports have been excellent. A single tablet daily, the same dose use clinically, seems to be all one needs for an exceptional effect (some even report excellent results with only 1/4 tablet daily). When used with strong, readily aromatizing androgens such as Dianabol or testosterone, gynecomastia and water retention can be effectively blocked. In combination with Propecia (finasteride), we have a great advance. With the one drug halting estrogen conversion and the other blocking 5-alpha reduction (testosterone, methyltestosterone and Halotestin only), related side effects can be effectively minimized. Here the strong androgen testosterone could theoretically provide incredible muscular growth, while at the same time being as tolerable as nandrolone. Additionally the quality of the muscle should be greater, the athlete appearing harder and much more defined without holding excess water.

There are some concerns with using an aromatase inhibitor such as this during prolonged steroid treatment however. While it will effectively reduce estrogenic side effects, it will also block the beneficial properties of estrogen from becoming apparent (namely its effect on cholesterol values). Studies have clearly shown that when an aromatase inhibitor is used in conjunction with a steroid such as testosterone, suppression of HDL (good) cholesterol becomes much more pronounced. Apparently estrogen plays a role in minimizing the negative impact of steroid use. Since the estrogen receptor antagonist Nolvadex does not display an anti-estrogenic effect on cholesterol values, it is the preferred from of estrogen maintenance for those concerned with cardiovascular health.
Femara has another principle drawback, namely the great price of this drug. Tablets can be quite costly with regular use, but it can ward off the side effects of strong androgens much better than Nolvadex and/or Proviron, making heavy cycles much more comfortable. As the number of countries manufacturing this drug increases, we may be able to look forward to a reduction in price. Privately compounded versions of "liquid Femara have also been formulated "for research purposes" and are currently circulating the black market. Generic tabs are also available and these two forms represent a very cost-effective alternative for buying the brand name drug.

Steroidology.com.

[heavyiron]

Biological and clinical effects of aromatase inhibitors in neoadjuvant therapy.

Miller WR (http://forums.rxmuscle.com/pubmed?term=%22Miller%20WR%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Dixon JM (http://forums.rxmuscle.com/pubmed?term=%22Dixon%20JM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Cameron DA (http://forums.rxmuscle.com/pubmed?term=%22Cameron%20DA%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Anderson TJ (http://forums.rxmuscle.com/pubmed?term=%22Anderson%20TJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Department of Clinical Oncology, and Breast Unit, Western General Hospital, University of Edinburgh, Crewe Road South, EH4 2XU, Edinburgh, UK. [email protected]

Postmenopausal women with large primary oestrogen receptor-rich (>20 fmol/mg protein or 80 histoscore) breast cancers have been treated neoadjuvantly with either letrozole (2.5 or 10 mg daily n=12 in each case) or anastrozole (1 or 10mg daily n=12 and 11, respectively). Tumour was available for analysis before treatment (wedge biopsy) and 3 months later at definitive surgery (wide local excision or mastectomy). Clinical response to treatment was assessed by sequential measurements of tumour volume based on caliper assessment, ultrasound and mammography. Results showed that in these selected groups of patients a reduction in tumour volume with treatment was observed in 43 of 47 cases (91%). Pathological responses, i.e. clear decrease in tumour cellularity or increased fibrosis was evident in 32 cases (68%). Furthermore, there was a decrease with therapy in immunohistochemical staining for Ki67 in all tumours. Staining for progesterone receptor (PgR) was reduced in all 21 PgR-positive cancers treated with letrozole and in 16 of 17 positive cancers treated with anastrozole. These effects are at least as great as those seen in a non-randomised group of patients treated with tamoxifen over the same time period (additionally tamoxifen treatment was often associated with an increase in PgR staining). The results suggest that potent specific aromatase inhibitors will be valuable in treating hormone-dependent cancers.

PMID: 11850213 [PubMed - indexed for MEDLINE]

[heavyiron]

This may be a basis for using Letro to reduce mammery gland tissue (gyno).



Aromatase overexpression transgenic mice model: cell type specific expression and use of letrozole to abrogate mammary hyperplasia without affecting normal physiology.

Mandava U (http://forums.rxmuscle.com/pubmed?term=%22Mandava%20U%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Kirma N (http://forums.rxmuscle.com/pubmed?term=%22Kirma%20N%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Tekmal RR (http://forums.rxmuscle.com/pubmed?term=%22Tekmal%20RR%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Department of Gynecology and Obstetrics, Emory University, 4217 Woodruff Memorial Building, 1639 Pierce Drive, Atlanta, GA 30322-4710, USA.

Our recent studies have shown that overexpression of aromatase results in increased tissue estrogenic activity and induction of hyperplastic and dysplastic lesions in female mammary glands and gynecomastia and testicular cancer in male aromatase transgenic mice. Both aromatase mRNA and protein are overexpressed in transgenic mammary glands and its expression is not limited to epithelial cells. However, it is more in epithelial than in stromal cells. Our results also indicate aromatase overexpression-induced changes in mammary glands can be abrogated with very low concentrations of the aromatase inhibitor, letrozole. Low concentration of letrozole had no effect on normal physiology as indicated by no significant change in the circulating levels of estradiol and follicle stimulating hormone as well as no change in estrogen responsive genes such as the progesterone receptor and lactoferrin in the uterine tissue. These observations indicate that the expression of aromatase in both epithelial and stromal cells can influence the complex interactions of biochemical pathways leading to mammary carcinogenesis and that the aromatase inhibitor, letrozole can be used as chemopreventive agents without affecting normal physiology.

PMID: 11850204 [PubMed - indexed for MEDLINE]

[heavyiron]

Use of the aromatase inhibitor letrozole to treat male infertility.

Patry G (http://forums.rxmuscle.com/pubmed?term=%22Patry%20G%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Jarvi K (http://forums.rxmuscle.com/pubmed?term=%22Jarvi%20K%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Grober ED (http://forums.rxmuscle.com/pubmed?term=%22Grober%20ED%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Lo KC (http://forums.rxmuscle.com/pubmed?term=%22Lo%20KC%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada. [email protected]

OBJECTIVE: Report the case of induction of spermatogenesis with the aromatase inhibitor letrozole. DESIGN: Case report. SETTING: University Infertility center. PATIENT(S): A 31-year-old man with primary infertility, normal volume azoospermia, normal follicle stimulating hormone (FSH) levels and pattern of nonobstructive azoospermia (NOA) on a testicular biopsy. INTERVENTION(S): The patient was given the aromatase inhibitor letrozole for 4 months and had repeated FSH, testosterone, LH levels, semen analyses, and finally a testicular biopsy. MAIN OUTCOME MEASURE(S): Results of a testis biopsy. RESULT(S): Testis biopsy showed normal spermatogenesis following 4 months of letrozole therapy. CONCLUSION(S): This is the first case report on the use of letrozole to treat male infertility and the first case report on the induction of spermatogenesis in a man with NOA using any aromatase inhibitor.

PMID: 19524225 [PubMed - indexed for MEDLINE]

[heavyiron]

Letrozole powerfully lowers Estradiol in women.




Use of ultrasensitive recombinant cell bioassay to measure estrogen levels in women with breast cancer receiving the aromatase inhibitor, letrozole.

Klein KO (http://forums.rxmuscle.com/pubmed?term=%22Klein%20KO%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Demers LM (http://forums.rxmuscle.com/pubmed?term=%22Demers%20LM%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Santner SJ (http://forums.rxmuscle.com/pubmed?term=%22Santner%20SJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Baron J (http://forums.rxmuscle.com/pubmed?term=%22Baron%20J%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Cutler GB Jr (http://forums.rxmuscle.com/pubmed?term=%22Cutler%20GB%20Jr%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract), Santen RJ (http://forums.rxmuscle.com/pubmed?term=%22Santen%20RJ%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Children's Hospital of Orange County, California 92668, USA.

The development of well tolerated, potent, specific, and nontoxic aromatase inhibitors for the treatment of postmenopausal women with estrogen-dependent breast cancer has been a major goal of recent studies. The third generation inhibitors now under investigation are nearly 10,000-fold more potent than first generation compounds. Currently available RIAs for plasma estradiol lack sufficient sensitivity to measure levels during aromatase inhibition and, thus, to assess drug potency precisely. The availability of an ultrasensitive bioassay for estradiol provided the opportunity to accurately assess the potency of a new third generation triazole aromatase inhibitor, letrozole (CGS 20267). We used this assay to measure estradiol levels in 14 women with metastatic breast cancer given letrozole at doses of 100 micrograms to 5.0 mg/day over a 12-week period. The lack of differences between doses and sampling times allowed pooling of data. Basal estradiol levels of 7.2 +/- 1.9 pmol/L (mean +/- SEM, 1.95 +/- 0.52 pg/mL) fell to 0.26 +/- 0.11 pmol/L (0.07 +/- 0.03 pg/mL) during the first 6 weeks of therapy and to 0.48 +/- 0.18 pmol/L (0.13 +/- 0.05 pg/mL) during the second 6 weeks of therapy. Although plasma estradiol levels measured by RIA were significantly correlated with levels measured by bioassay (r = 0.79; P < 0.01), the degree of suppression assessed by the bioassay (95 +/- 2% after 6 weeks) was greater than that determined by the RIA (81 +/- 4%), presumably due to improved ability to measure very low estradiol levels. We conclude that plasma estradiol is suppressed by letrozole to lower levels than previously observed, with equivalent suppression at all doses studied. A slight, although not statistically significant, rebound in estradiol levels occurs during the second 6 weeks of therapy compared to the first 6 weeks. Maximum inhibition of aromatase is achieved at letrozole doses as low as 100 micrograms.

PMID: 7673408 [PubMed - indexed for MEDLINE]

[heavyiron]

Letrozole takes a very long time for steady state plasma levels compared to other Aromatase Inhibitors.




Pharmacology and pharmacokinetics of the newer generation aromatase inhibitors.

Buzdar AU (http://forums.rxmuscle.com/pubmed?term=%22Buzdar%20AU%22%5BAuthor%5D&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsP anel.Pubmed_RVAbstract).
Department of Breast Medical Oncology, The University of Texas M D Anderson Cancer Center, Houston, Texas 77030, USA. [email protected]

The newer generation aromatase inhibitors (AIs) as a class show efficacy and tolerability benefits over previously established treatments in postmenopausal women with advanced breast cancer. At clinically administered doses, the plasma half-lives of anastrozole (1 mg once daily), letrozole (2.5 mg once daily), and exemestane (25 mg once daily) are 41-48 h, 2-4 days, and 27 h, respectively. Time to steady-state plasma levels is 7 days for both anastrozole and exemestane and 60 days for letrozole. Androgenic side effects have only been reported with exemestane. Anastrozole treatment has no impact on plasma lipid levels, whereas both letrozole and exemestane have an unfavorable effect. From indirect comparisons, anastrozole shows the highest degree of selectivity compared with letrozole and exemestane, in terms of a lack of effect on adrenosteroidogenesis. To date, there are no data suggesting any major differences in clinical efficacy between the newer generation AIs anastrozole and letrozole. Based on the observed pharmacological profiles, however, it cannot be assumed that the AIs will display the same tolerability and safety profiles when given for extended periods of time in the adjuvant setting. The effects of anastrozole, letrozole, and exemestane are being investigated in the adjuvant setting, and these data will elucidate the possible long-term consequences of the pharmacological effects reported after short-term exposure.

PMID: 12538502 [PubMed - indexed for MEDLINE]

[D_T]

I like it because I can use so little it lasts forever. A 30ml bottle lasted 2 years and it was still potent at the end. I noticed a difference within 2 weeks of running out.

[ArabMuscle]

Great information Heavy! 1/4 tab every 3 days is more than enough. I used to take in 1/2 tab EOD and it killed my libido.

In regards to minimizing gyno, it definitely works. I'd like to add that gyno symptoms started appearing, including lumps behind both nipples. I took in 1/2 a tab (in accordance to Heavy's instructions) ED for a week then tapered it down to EOD then finally 1/4 E3D.

The lumps shrunk and the fat around them decreased significantly. However after treatmeant, my physique was too dry and my libido was terrible. Fortunately, it bounced back once I tapered it down to E3D.

[heavyiron]

Great information Heavy! 1/4 tab every 3 days is more than enough. I used to take in 1/2 tab EOD and it killed my libido.

In regards to minimizing gyno, it definitely works. I'd like to add that gyno symptoms started appearing, including lumps behind both nipples. I took in 1/2 a tab (in accordance to Heavy's instructions) ED for a week then tapered it down to EOD then finally 1/4 E3D.

The lumps shrunk and the fat around them decreased significantly. However after treatmeant, my physique was too dry and my libido was terrible. Fortunately, it bounced back once I tapered it down to E3D.
Good to know. Letro is quite strong and effective.

[s2h]

Hey Heavy had a guy today ask me if I thought it was safe for him to run 250mg a week of test.He had bad gyno and had the total gland removed,but his doc said he could still get gyno again?????so i told him get some letro,keep it handy and if you get any sides to start asap,do you think thats a good plan(he's about late 20's used a shit load of pro-h to get the gyno)

[heavyiron]

Hey Heavy had a guy today ask me if I thought it was safe for him to run 250mg a week of test.He had bad gyno and had the total gland removed,but his doc said he could still get gyno again?????so i told him get some letro,keep it handy and if you get any sides to start asap,do you think thats a good plan(he's about late 20's used a shit load of pro-h to get the gyno)
I would just run Aromasin. At the correct dose gyno is impossible.

[MrOXY]

I would just run Aromasin. At the correct dose gyno is impossible.
What dose do u recomend?

[heavyiron]

What dose do u recomend?
Usually 10mg daily is good but if I increase my aromatizing compounds I may take 25mg Aromasin daily. Only labs can dial you in so these are general doses.

[bad rad]

I'm reading the package insert (just bought 85 2.5mg tabs) and it states,

Co-administration of Letrozole and Tamoxifen 20mg daily resulted in a reduction of Letrozole plasma levels of 38% on average. Clinical experience in pivotal trials indicates that the therapeutic effect of Letrozole therapy is not impaired is Letrozole is administered immediately after Tamoxifen.

I thought it was interesting, probably not an issue for us because we tend to use one or the other. In the past I have used AI and anti-E together but rarely. The 38% drop is substantial when you look at how strong Letro is per dose to begin with. Also out of 3 different brands only one had this in the write up.

[s2h]

I would just run Aromasin. At the correct dose gyno is impossible.
that's what i told him,i think his Doc was just tryn to scare him from using any AAS

[bad rad]

Another study on 12 men using 2.5mgs weekly to normalize HPTA from obesity induced suppression.

http://www.eje-online.org/cgi/reprint/158/5/741.pdf

[bad rad]

Another good one using high doses of Letrozole, the T increases were over 300%.

http://jcem.endojournals.org/cgi/reprint/90/10/5717

[bringingthehuge]

What is the best way to use Letrozole ?( dosage and duration)

[mr intensity]

hey heavy iron,
is there any relation between SHBG levels, and letrozole...all i knew was to either use stanazolol 50mg eod or proviron.... some guy told me about letrozole greatly reduces SHBG levels... need to know if it is correct...

thanks

[heavyiron]

hey heavy iron,
is there any relation between SHBG levels, and letrozole...all i knew was to either use stanazolol 50mg eod or proviron.... some guy told me about letrozole greatly reduces SHBG levels... need to know if it is correct...

thanks
Letro does lower SHBG some.

[Jermo]

http://jcem.endojournals.org/content/90/10/5717.short

Comparative Assessment in Young and Elderly Men of the Gonadotropin Response to Aromatase Inhibition



Guy G. T’Sjoen (http://jcem.endojournals.org/search?author1=Guy+G.+T%E2%80%99Sjoen&sortspec=date&submit=Submit),
Vito A. Giagulli (http://jcem.endojournals.org/search?author1=Vito+A.+Giagulli&sortspec=date&submit=Submit),
Hans Delva (http://jcem.endojournals.org/search?author1=Hans+Delva&sortspec=date&submit=Submit),
Patricia Crabbe (http://jcem.endojournals.org/search?author1=Patricia+Crabbe&sortspec=date&submit=Submit),
Dirk De Bacquer (http://jcem.endojournals.org/search?author1=Dirk+De+Bacquer&sortspec=date&submit=Submit) and
Jean-Marc Kaufman (http://jcem.endojournals.org/search?author1=Jean-Marc+Kaufman&sortspec=date&submit=Submit)

- (http://jcem.endojournals.org/content/90/10/5717.short#) Author Affiliations


Department of Endocrinology (G.G.T., H.D., P.C., J.-M.K.), Ghent University Hospital, 9000 Ghent, Belgium; Department of Public Health (D.D.B.), Ghent University, 9000 Ghent, Belgium; and Department of Internal Medicine Subdivision Endocrinology (V.A.G.), Ospedale Putignano-Noci, 70017 Bari, Italy



Address all correspondence and requests for reprints to: G. T’Sjoen, M.D., Department of Endocrinology, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium. E-mail: [email protected].


Abstract

Context: Aging in men is associated with a decline in serum testosterone (T) levels.
Objective: Our objective was to assess whether decreased T in aging might result from increased estradiol (E2) negative feedback on gonadotropin secretion.
Design and Setting: We conducted a comparative intervention study (2004) in the Outpatient Endocrinology Clinic, Ghent University Hospital.
Participants: Participants included healthy young and elderly men (n = 10 vs. 10).
Interventions: We used placebo and letrozole (2.5 mg/d) for 28 d, separated by 2 wk washout.
Main Outcome Measures: We assessed changes in serum levels of free E2, LH, and FSH, free T, SHBG, and gonadotropins response to an iv 2.5-μg GnRH bolus.
Results: As assessed after 28 d of treatment, letrozole lowered E2 by 46% in the young men (P = 0.002) and 62% in the elderly men (P < 0.001). In both age groups, letrozole, but not placebo, significantly increased LH levels (339 and 323% in the young and the elderly, respectively) and T (146 and 99%, respectively) (P value of young vs. elderly was not significant). Under letrozole, peak LH response to GnRH was 152 and 52% increase from baseline in young and older men, respectively (P = 0.01).
Conclusions: Aromatase inhibition markedly increased basal LH and T levels and the LH response to GnRH in both young and elderly men. The observation of similar to greater LH responses in the young compared with the elderly does not support the hypothesis that increased restraining of LH secretion by endogenous estrogens is instrumental in age-related decline of Leydig cell function.



Received May 3, 2005.
Accepted July 18, 2005.

[Jermo]

Note that Letro does not lower E2 by 98% as some claim. But instead by about 50% just like any other AI. And that's on young and elderly men who are not on exogeneous suprphysiological doses of testosterone either. 98% E2 reduction was noted in a study done on women with breast cancer.

[heavyiron]

Note that Letro does not lower E2 by 98% as some claim. But instead by about 50% just like any other AI. And that's on young and elderly men who are not on exogeneous suprphysiological doses of testosterone either. 98% E2 reduction was noted in a study done on women with breast cancer.
Yup, I have been making this point for a long time now. Female studies are useless when it comes to E2 suppression from AI's in men.

[adpolice]

So then it comes the late debate,test+a.i pre contest or non aromatize anabolics?Personal experience proved that the second option is best...Even at 5mg of letro per day my estrogen were still high at 750mg of test per week and i had to use a lot of diuretics to drop the water,i end up flat and bad..my first contest i droped test the last 3weeks and used masteron+var only,i came up hard and dry without even using a diuretic...The conclusion is use your ai to control estro levels but still they will be higher than normal,not optimal when chasing perfection..

[heavyiron]

So then it comes the late debate,test+a.i pre contest or non aromatize anabolics?Personal experience proved that the second option is best...Even at 5mg of letro per day my estrogen were still high at 750mg of test per week and i had to use a lot of diuretics to drop the water,i end up flat and bad..my first contest i droped test the last 3weeks and used masteron+var only,i came up hard and dry without even using a diuretic...The conclusion is use your ai to control estro levels but still they will be higher than normal,not optimal when chasing perfection..
All good points brother.

[Jermo]

Looks like I'll be dropping my test 3 weeks out then, lol

[fishmeat]

Tren,halo, masteron & Anavar....One fuckin incredible stage stack!!!

[BlueBaron]

A friend said that Letro would get rid of entirely starting gyno, Although after doing my research on here i don't think he's right. What is the truth? Just curious. Thank you

[heavyiron]

A friend said that Letro would get rid of entirely starting gyno, Although after doing my research on here i don't think he's right. What is the truth? Just curious. Thank you
Post #3 is good evidence that Letro does cure/reduce new gyno symptoms. I would definitely give it a try before opting for surgery brother.

[jwerge]

Yup, I have been making this point for a long time now. Female studies are useless when it comes to E2 suppression from AI's in men.

If it only blocks about 50% of E2, then what is the reason to use it over aromasin, adex etc. ?