T Nation

High SHBG Due to Estriol?


I've been having symptoms associated with low free testosterone for several years now (low libido, lack of energy/drive, brain fog, etc). I think this is because my SHBG level is abnormally high, but I'm not sure why. I don't fit any of the usual explanations for high SHBG, EXCEPT that my Estriol (E3) level is high.

My E1 & E2 are both well within range, so my questions are:

1) Can E3 itself drive up SHBG so that it's abnormally high? (I think I've seen KSman imply that it can)

2) If so, what can be done about it?

Thanks for any help you are able to offer.


SHBG may driven up from Gut and liver inflammation. It is also driven up by xenobiotics from our environment. If you are any specific type of medicines (antibiotics, blood pressure meds, thyroid, etc) it can also be increased. The best suggestion is to evaluate the persons detailed symptoms and history to possible determine the pathology of the issue.


Dietary isoflavones are thought to increase SHBG. Are you avoiding soy products?


Thank you both for your replies.

Nails, I have been following a protocol for reducing inflammation and I have to say that my brain fog has got a lot better. No improvement on the other symptoms though…I’m hoping that might follow.

KSman, yes I’m avoiding soy. Have never eaten much soy, and did realise my protein powder contained it but stopped using that several weeks ago.


I tried to find articles for SHBG+estriol and nothing valuable was found and what you will find is in the context of female issues and nothing seems to isolate estriol. What would need to be done is to have a person with normal levels take doses of estriol and see how serum SHBG responds. In doing that, estriol probably reduces LH/FSH levels and other ovarian or testicular hormones would then be expected to fall. So you would never get a pure estriol science experiment.

Estrogen metabolism can be adverse if gut flora is abnormal. Digestive issues? You can try a good probiotic. Most products are crap. Look for a product in a health food store or department. Look for a product that is refrigerated.


Thanks KSman, I appreciate you looking into this. It’s encouraging that you suggest digestive issues, as I’ve just had a test back that has confirmed this (leaky gut and such like). I wasn’t sure when I ordered the test whether gut issues would explain all the symptoms I have, so it’s good to know that you and Nails feel it might explain things. I’ll try your suggestion, thanks.


Excess thyroid hormones can increase SHBG.