Hypogonadism

Hypogonadism is low production of sex hormones. In men it refers to low testosterone together with symptoms.

A key distinction: true (pathologic) hypogonadism comes from disorders of the hormonal axis and generally needs lifelong testosterone replacement, whereas the mild low testosterone common in obesity is usually reversible — driven largely by reduced SHBG and often corrected by weight loss. See the guide on HRT for men and GLP-1 medications.

Related terms

Testosterone replacement therapy (TRT) — Replacing testosterone in men who have hypogonadism (clinically low testosterone plus symptoms), delivered as a gel, injection, patch, or pellet. It is for a specific diagnosis, not a default treatment for the reversible low testosterone that often accompanies obesity.

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.

Menopausal hormone therapy (MHT) — Estrogen, usually combined with a progestogen (when the uterus is present), used to relieve menopausal symptoms such as hot flashes and to protect bone. Often just called 'HRT.' It is associated with less visceral fat but is not a weight-loss treatment.

Related guides

HRT for men (testosterone) and GLP-1 medications: what the connection really is — Low testosterone and excess weight are linked — but the arrow often points from weight to testosterone, not the other way, and that changes when testosterone therapy actually helps. Here's who benefits from TRT, and why losing weight on a GLP-1 can raise testosterone on its own.

How GLP-1 medications affect men vs. women: what the sex differences actually are — The same GLP-1 medication doesn't act quite the same in men and women. On average women lose more weight, get more side effects, and even absorb more of the drug at the same body weight — differences driven partly by estrogen and testosterone. Here's what the research shows about sex differences in weight loss, tolerability, blood sugar, and biology, and what it means for what you should expect.

Men's health on a GLP-1: testosterone, fertility, muscle, and the things worth watching — For men, losing weight on a GLP-1 does more than shrink the scale — it can raise testosterone that obesity was quietly suppressing, and unlike testosterone therapy it tends to preserve fertility. Here are the key men's-health angles the research is starting to fill in: the testosterone connection, sexual function and sperm, protecting muscle and bone, cardiovascular benefit, and sleep apnea — plus why the checkup men tend to skip matters more now.