<p>Low testosterone in men causes loss of muscle mass, decreased energy and libido, and infertility.&nbsp; These generalized symptoms are a result of&nbsp; &nbsp;testosterone hormone affecting variety of different organs and tissue in the body.</p>

<p>In young adults and adolescents, difficulty gaining muscle mass despite strength resistance exercise and failure of development of facial beard and deepening of voice&nbsp; suggest low testosterone.</p>

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