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Saturday, May 24, 2014

Estrogen Rather Than Testosterone Might Be The Key To Libido

Common and accepted medical belief was that testosterone was associated with libido.  This was due to an association with low T and low libido.  But those of us in the field of men's health recognized that low T did not tell the entire story.  While some men with very low T AND low libido reported improved libido with normalized T levels, the improvements were inconsistent as best and not linear in nature.  By that I mean that after a certain T level was reached, further increases in T did not result in further improvements in libido.

Estrogen: Estrogen and Testosterone are intimately related.  Estrogen in fact comes from testosterone via conversion by aromatase, an enzyme.  Men with low T will also have low E levels and increasing T levels with medication will also increase E levels. Rising E levels in a man on testosterone therapy can cause gynecomastia, which is breast development.  As gynecomastia is an adverse outcome, doctors that do TRT monitor E levels and treat rising E with an aromatase inhibitor like Anastrozole.  I used to do this as well, and still do but much less often than in the past.  Why?  Because I noticed that some of my men on Anastrozole began complaining of dimished libido.  Research studies presented at this AUA14 supported what I noticed several years ago.

Conclusion: estrogen and testosterone are linked and both are needed for libido, but estrogen might be the more important of the 2 hormones in relation to libido.  More studies are needed.

Thanks,
Dr Schoor