Testosterone: it’s a powerhouse hormone that fuels men’s energy, focus, mood, and vitality at every age. Yet despite its importance, testosterone is surrounded by confusion, stigma, and half-truths.

In this accessible, myth-busting guide, leading endocrinologist Dr Jeff Foster sets the record straight. Drawing on years of clinical experience, he explains how testosterone really works; why deficiency is far more common than most people think, and how it can impact everything from sleep to mental health, strength to sex, and overall wellbeing.

Learn how to spot the signs of low testosterone; what modern treatments can (and can’t) do, and why looking after your hormone health is one of the best investments you can make for your future.

Testosterone is not simply about muscles and libido. It’s about health, confidence, and living life to the fullest.

Dr Jeff Foster BSc (Hons), MB ChB, DRCOG, MRCGP is an NHS GP Partner, and Private GP with a specialist interest in Men’s Health.

In addition to his NHS work, Dr Foster is the Director of Men’s Health at Manual and also the Medical Director and founder of H3 Health, the U.K.’s first male and female health clinic aimed primarily at those over 40.

Dr Foster is passionate about raising awareness of all aspects of Men’s Health, and is heavily involved in both teaching and health promotion. He is a committee member of the British Society of Sexual Medicine, and has been involved in writing the most recent national guidelines for testosterone deficiency in men.