Hormones & Testosterone

Clear explanations of testosterone, cortisol, thyroid and other hormones that shape men's health.

Hypothyroidism Symptoms in Men: Low Thyroid and Low Drive

Short answer: The most common hypothyroidism symptoms in men are fatigue, weight gain, feeling cold, constipation, dry skin, muscle aches, low mood and a slowed heart rate. Low sex drive is also common: in one multicenter study, most men with an underactive thyroid reported low desire or ejaculation problems, and many improved once thyroid levels…

Free vs Total Testosterone: What Your Results Mean

A side-by-side comparison of free and total testosterone, the role of SHBG, and what to ask your doctor about your results.

Metformin and Testosterone: What the Research Really Shows

Short answer: A few short studies in men with type 2 diabetes found that men taking metformin had lower testosterone after one to three months than men treated without it, but the drop was modest and the evidence is limited. Type 2 diabetes and excess body weight are themselves strongly linked to low testosterone, so…

Shift Work Sleep Disorder and Testosterone: What Night Workers Should Know

Short answer: Shift work sleep disorder (SWSD) is a circadian rhythm sleep disorder in people who work nights, early mornings or rotating shifts, marked by insomnia when you try to sleep and heavy sleepiness when you need to be awake. For men, it matters beyond fatigue: in a clinic study of 2,571 men, shift workers…

Does Fasting Increase Testosterone? What Intermittent Fasting Studies Show

Short answer: No, fasting does not appear to increase testosterone in lean, healthy men. In the controlled human trials that measured it, time-restricted eating (such as the 16:8 schedule) left testosterone unchanged or lowered it, even though men kept their muscle and strength. The one route by which fasting may help testosterone is indirect: if…

How to Lower Cortisol: Stress, Low Energy and When to See a Doctor

Short answer: For most men, the practical way to lower cortisol is to fix the daily inputs that keep the stress response switched on: regular sleep and wake times, regular exercise, a nutritious diet, deliberate relaxation (such as slow deep breathing), and less reliance on alcohol or late screens. If low energy comes with unexplained…