How does estrogen affect the female body?

In many ways, I’m sure, but let’s focus on muscle growth for now.

Estrogen builds muscle: hundreds of studies show this [Brown 2013]. Estrogen encourages the body to add more muscle nuclei to muscle fibers, and those are essentially “muscle building factories” [Enns & Tiidus 2010]. 

More factories, more capacity for the muscle to growth [Bruusgaard 2010].

To give you an idea of how potent estrogen is: post-menopausal women with low estrogen levels gained more muscle by taking estrogen tablets and sitting on the couch all day than taking no tablets and doing regular weight training [Sipilä 2001].

As a final note, even things like eating more soy products may enhance muscle growth – since they have estrogen-like isoflavones in them – without affecting natural estrogen levels [Leung 2004]. See my earlier post on how soy intake affect natural estrogen levels in women here: