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Functional hypogonadism

Low testosterone in men caused by a reversible condition — most often obesity — rather than a disorder of the hormonal axis; it usually improves with weight loss and generally does not need testosterone therapy.

By the glp1.how editorial teamReviewed

Functional hypogonadism is the term for low testosterone in men that stems from a reversible condition — obesity above all, but also type 2 diabetes, obstructive sleep apnea, depression, and certain medications — rather than from a structural or genetic disorder of the testes or pituitary. The pituitary signals (LH and FSH) are usually low or inappropriately normal, not raised the way they are when the testes themselves fail, and much of the measured drop reflects lower levels of the carrier protein SHBG. Some endocrinologists prefer to call the obesity-related form a "pseudo-hypogonadism" for that reason.

The distinction matters because the treatment is different. True, pathologic hypogonadism generally needs lifelong testosterone replacement; the functional kind usually improves when the underlying cause is treated — and weight loss, including on a GLP-1, tends to raise testosterone on its own. Testosterone therapy given for the functional form carries real downsides (impaired fertility, thicker blood, dependence) without fixing the cause. See the guide on HRT for men and GLP-1 medications. Source: Grossmann and Matsumoto, Journal of Clinical Endocrinology & Metabolism, 2017 (external link).

testosteronemenobesityhormones

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Related terms

  • Hypogonadism · A condition of low sex-hormone production. In men it means low testosterone with symptoms; importantly, the low testosterone that often accompanies obesity is frequently a reversible state ('pseudo-hypogonadism') rather than true, pathologic hypogonadism.
  • Obstructive sleep apnea · A sleep disorder in which the airway repeatedly collapses during sleep, causing brief pauses in breathing; it is closely linked to obesity.
  • LH and FSH · Luteinizing hormone and follicle-stimulating hormone: two pituitary hormones that signal the testes and ovaries to make sex hormones and sperm or eggs.
  • SHBG (sex hormone-binding globulin) · A protein that binds and transports sex hormones (including testosterone) in the blood. Obesity lowers SHBG, which reduces measured total testosterone and is a major reason obesity can look like low testosterone on a lab test.
  • GLP-1 · A gut hormone (glucagon-like peptide-1) that stimulates insulin release, slows digestion, and reduces appetite; the target of drugs like semaglutide and liraglutide.

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