To say that estrogens upregulate the androgen receptor in human skeletal muscle is a stretch. Estrogens work via the estrogen receptor, except for a few poorly characterized non genomic actions, and some possible actions by direct binding to the androgen receptor in the prostate. Estrogen receptor mRNA was only just recently discovered in human skeletal muscle (1). Prior to that, it was believed that human skeletal muscle lacked the estrogen receptor (2). So it is really premature to start ascribing anabolic effects to estrogen in humans that may or may not even exist in animals and certainly have never been demonstrated in humans

There is also evidence that estrogens may have a negative impact on muscle recovery:

"More recently, investigations into the potential effect of estrogen on muscle damage have explored the possible role that estrogen may play in the inflammatory response following muscle damage. In light of these studies, it may be suggested that if estrogen inhibits the vital inflammatory response process associated with the muscle damage and repair cycle, it has a negative role in restoring normal muscle function after muscle damage has occurred."(3)

Normal cellular hydration may be important for GH release and glucose uptake, but there is no evidence that estrogen induced edema enhances these effects.

It is important here to distinguish one person's speculation from what is documented in the scientific literature. There is nothing wrong with theorizing, But readers must realize that is all it is: speculation.

If I had to choose between a possible loss in gains versus a good chance of developing gyno, based on the published scientific research.. It's a no brainer.


(1) Med Sci Sports Exerc 2003 Mar;35(3):439-43

Estrogen receptor alpha mRNA in human skeletal muscles.

Lemoine S, Granier P, Tiffoche C, Rannou-Bekono F, Thieulant ML, Delamarche P.

(2) Prog Clin Biol Res 1984;142:261-90

Studies on steroid receptors in human and rabbit skeletal muscle - clues to the understanding of the mechanism of action of anabolic steroids .

Gustafsson JA, Saartok T, Dahlberg E, Snochowski M, Haggmark T, Eriksson E

(3) Sports Med 2002;32(2):103-23

Exercise-induced muscle damage and the potential protective role of estrogen.

Kendall B, Eston R.