Raloxifene: anti-oestrogen that boosts lean body mass and reduces fat

Definition: "An ergogenic aid is any substance or phenomenon that enhances performance "

11.03.2014

Anti-oestrogens & body composition
Chemical athletes use tamoxifen to counteract the oestrogenic side effects of the anabolic steroids they take, but also to boost their testosterone levels and reduce the effects of estradiol between courses of steroids.

Tamoxifen, an effective anti-oestrogen that's popular among doping users, has a drawback. For women at least, in the longer term, its use reduces lean body mass and leads to an increase in fat mass. Another anti-oestrogen, raloxifene [structural formula on the right], does not have these disadvantages. A Dutch study suggests that it actually improves body composition.
Very few scientific studies have been published on the exact effects of tamoxifen on chemical athletes. More is known about the effects of tamoxifen in women who have survived breast cancer.

Tamoxifen boosts these women's chances of survival considerably, and reduces the chance of estradiol-sensitive forms of breast cancer returning. That's why doctors often prescribe tamoxifen for years after initial breast cancer treatment.

The price that these women pay for their increased chance of survival is worsening of their body composition, however. [Breast Cancer Res Treat. 2012 Oct;135(3):663-80.] Their lean body mass – or in other words their muscle mass – reduces and their body fat increases. Strength training can counteract this effect though.

Study

Tamoxifen, an effective anti-oestrogen that's popular among doping users, has a drawback. For women at least, in the longer term, its use reduces lean body mass and leads to an increase in fat mass. Another anti-oestrogen, raloxifene [structural formula on the right], does not have these disadvantages. A Dutch study suggests that it actually improves body composition.
In 2010 geriatricians in Utrecht published a study from which it's possible to deduce that raloxifene does not have a negative effect on body composition. Raloxifene is marketed under the name of Evista by Eli Lilly. The manufacturer provided the medicines used in the study, but did not sponsor the study. The researchers were funded by the Dutch government.

In the study one group of 70 women aged between 70 and 80 took 60 mg raloxifene daily. Another group of 73 women were given a placebo.

Results
The figure below shows how raloxifene altered the women's body composition: it reduced their fat mass, but also increased lean body mass.

Raloxifene did not boost the women's muscle strength, but it did improve some memory functions. [Menopause. 2010 Mar;17(2):309-14.]

Conclusion
"The clinical impact of this finding warrants further research", the researchers conclude.

Source:
Eur J Endocrinol. 2010 Feb;162(2):371-6.

More:
Why raloxifene is safer than tamoxifen 26.09.2011