Effect of Tamoxifen Citrate on IGF-1 levels

[Handle2]

My doctor told me that he would agree to prescribe me HGH if a blood test shows that my IGF-1 level is low.
Given that I am already taking 45mg testosterone cypionate twice a week, I assume that my IGF-1 level would not be low.
Nevertheless, I am curious to try HGH to see what effect it has on my body.
I remember reading somewhere that taking tamoxifen citrate will lower IGF-1 levels. If this is true, how much would I likely need to take and for how long to suppress my IGF-1 levels?

 

[blazinshotguns]

Take that and take adex . You want to crash your estrogen that lowers your igf. Combine that with Clomid .

 

[Michael Scally MD]

Birzniece V, Sata A, Sutanto S, Ho KKY. Neuroendocrine Regulation of Growth Hormone and Androgen Axes by Selective Estrogen Receptor Modulators in Healthy Men. J Clin Endocrinol Metab:jc.2010-1477. http://jcem.endojournals.org/content/95/12/5443.full (An Error Occurred Setting Your User Cookie)

Context: In men, the stimulation of GH and inhibition of LH secretion by testosterone requires aromatization to estradiol. Tamoxifen, a selective estrogen receptor modulator (SERM), possesses central estrogen antagonistic effect but peripheral hepatic agonist effect, lowering IGF-I. Thus, tamoxifen is likely to perturb the neuroendocrine regulation of GH and gonadal axes. Raloxifene, a SERM, is used for therapy of osteoporosis in both sexes. Its neuroendocrine effects in men are poorly understood.

Objective: The aim was to compare the impact of raloxifene and tamoxifen on GH-IGF-I and gonadal axes in healthy men.

Design: We conducted a randomized, open-label crossover study.

Patients and Intervention: Ten healthy men were randomized to 2-wk sequential treatment with tamoxifen(10 and 20 mg/d) and raloxifene (60 and 120 mg/d), with a 2-wk intervening washout period.

Main Outcome Measures: We measured the GH response to arginine and circulating levels of IGF-I, LH, FSH, testosterone, and SHBG.

Results: Tamoxifen, but not raloxifene, significantly reduced IGF-I levels by 25 {+/-} 6% (P < 0.01) and increased SHBG levels by 20 {+/-} 7% (P < 0.05) at the higher therapeutic dose. There was a nonstatistically significant trend toward a reduction in the GH response to arginine with both SERMs. Both drugs significantly increased LH, FSH, and testosterone concentrations. The mean increase in testosterone (40 vs. 25%; P < 0.05) and LH (70 vs. 30%; P < 0.01) was significantly greater with tamoxifen than with raloxifene treatment.

Conclusions: Tamoxifen, but not raloxifene, reduces IGF-I levels. Both SERMs stimulate the gonadal axis, with tamoxifen imparting a greater effect. We conclude that in therapeutic doses, raloxifene perturbs the GH and gonadal axes to a lesser degree than tamoxifen.

 

[Paul_Johnson]

Birzniece V, Sata A, Sutanto S, Ho KKY. Neuroendocrine Regulation of Growth Hormone and Androgen Axes by Selective Estrogen Receptor Modulators in Healthy Men. J Clin Endocrinol Metab:jc.2010-1477. http://jcem.endojournals.org/content/95/12/5443.full (An Error Occurred Setting Your User Cookie)

Context: In men, the stimulation of GH and inhibition of LH secretion by testosterone requires aromatization to estradiol. Tamoxifen, a selective estrogen receptor modulator (SERM), possesses central estrogen antagonistic effect but peripheral hepatic agonist effect, lowering IGF-I. Thus, tamoxifen is likely to perturb the neuroendocrine regulation of GH and gonadal axes. Raloxifene, a SERM, is used for therapy of osteoporosis in both sexes. Its neuroendocrine effects in men are poorly understood.

Objective: The aim was to compare the impact of raloxifene and tamoxifen on GH-IGF-I and gonadal axes in healthy men.

Design: We conducted a randomized, open-label crossover study.

Patients and Intervention: Ten healthy men were randomized to 2-wk sequential treatment with tamoxifen(10 and 20 mg/d) and raloxifene (60 and 120 mg/d), with a 2-wk intervening washout period.

Main Outcome Measures: We measured the GH response to arginine and circulating levels of IGF-I, LH, FSH, testosterone, and SHBG.

Results: Tamoxifen, but not raloxifene, significantly reduced IGF-I levels by 25 {+/-} 6% (P < 0.01) and increased SHBG levels by 20 {+/-} 7% (P < 0.05) at the higher therapeutic dose. There was a nonstatistically significant trend toward a reduction in the GH response to arginine with both SERMs. Both drugs significantly increased LH, FSH, and testosterone concentrations. The mean increase in testosterone (40 vs. 25%; P < 0.05) and LH (70 vs. 30%; P < 0.01) was significantly greater with tamoxifen than with raloxifene treatment.

Conclusions: Tamoxifen, but not raloxifene, reduces IGF-I levels. Both SERMs stimulate the gonadal axis, with tamoxifen imparting a greater effect. We conclude that in therapeutic doses, raloxifene perturbs the GH and gonadal axes to a lesser degree than tamoxifen.

why in the world would there be such a difference between the two? Doc!???