Also called: Low T; male hypogonadism; andropause; obesity-related low testosterone

Exercise strongly helps Strength

Low energy, low libido, poor recovery and muscle that will not build. In midlife the usual cause is a loop rather than a failing testis - belly fat converts testosterone to oestrogen, sleep apnoea lowers it further, and muscle loss makes both worse.

How common: 6-12% of men in their 40s, about 20% over 60 and half over 80 have low levels on blood tests; obesity is the commonest reversible cause

What it is

Testosterone falls slowly with age, but the large drops seen in midlife men are usually driven by something rather than by ageing alone. Fat tissue contains aromatase, which converts testosterone to oestrogen; the resulting higher oestrogen suppresses the brain's signal to the testes; and less testosterone means less muscle and more fat.

That loop is the point. It is self-reinforcing, and it is reversible from several directions - weight loss, resistance training, treating sleep apnoea and improving sleep all raise testosterone. This is why the first response to a borderline level in an overweight midlife man should usually be to address the loop rather than to prescribe.

What it feels like

  • Low energy and motivation that has crept up over a year or two
  • Reduced libido and, sometimes, erectile difficulty
  • Muscle that will not build despite training, and strength drifting down
  • Weight gain around the middle
  • Low mood, irritability and poor concentration

What causes it

Most people have more than one of these at once, and they feed each other. Read the list looking for the two or three that sound like your week rather than for the one true answer — the ones that describe you are the ones worth acting on.

Abdominal fat converting testosterone to oestrogen
Fat tissue contains the aromatase enzyme. More fat means more conversion, and the resulting oestrogen feeds back to suppress the pituitary signal driving testosterone production. It is the central mechanism in most midlife cases.
Suppression of the brain's signal
The hypothalamus and pituitary drive testicular production. Obesity, poor sleep, chronic illness and stress all reduce that signal, producing low testosterone with a normal testis.
Obstructive sleep apnoea
Strongly associated with low testosterone, independently of weight. Treating apnoea raises levels, and it is one of the most commonly missed contributors.
Poor and short sleep
Testosterone is produced largely during sleep. Restricting sleep to five hours a night lowers levels measurably in healthy young men within a week.
Muscle loss
Less muscle worsens insulin sensitivity and body composition, both of which feed the loop. Resistance training raises testosterone modestly and improves everything the low level was causing.
Age
A genuine gradual decline of around one per cent a year from midlife. It is real and it is much smaller than the drop produced by the loop above.
Medications
Opioids are a major and under-recognised cause, as are long-term steroids and some antifungals. Anabolic steroid use suppresses natural production, sometimes permanently.
Chronic illness and stress
Any significant illness suppresses testosterone as part of a general shift away from anabolic processes. Sustained stress does the same through cortisol.
Genuine testicular failure - the different one
Primary hypogonadism from testicular injury, infection, chemotherapy or genetic causes needs a different approach. High signalling hormones with low testosterone identifies it, which is why the blood test needs to be a proper one rather than a single number.

Who tends to get it

  • Men with central obesity, in whom the loop is most active
  • Anyone with sleep apnoea or chronically short sleep
  • Men taking long-term opioids or steroids
  • Anyone with type 2 diabetes or metabolic syndrome
  • Former anabolic steroid users

What makes it worse, and what settles it

Makes it worse

  • Weight gain around the middle, which drives the conversion
  • Short and disrupted sleep
  • Untreated sleep apnoea
  • Alcohol, which lowers testosterone directly at higher intakes
  • Starting testosterone replacement without addressing the loop, which suppresses natural production further

Settles it

  • Resistance training, which raises testosterone modestly and improves everything the low level was producing
  • Losing abdominal fat, which reduces the conversion and lifts the suppression
  • Treating sleep apnoea and prioritising sleep duration
  • Reducing alcohol
  • Getting a proper assessment - a morning sample, repeated, with the pituitary hormones measured - before any treatment decision

What actually helps

The short version: Belly fat converts testosterone to estrogen and suppresses the signal from the brain, sleep apnea and poor sleep lower it further, and muscle loss then makes all of it worse. Most mid-life low testosterone is this loop rather than a failing testis, which is why it reverses with weight loss and training

Strength work: Full Body; Weight Training; Legs: Quads; Glutes: Max; Back: Lats; Chest: Pecs; High-Intensity Interval Training - heavy compound lifting with short rests, three times a week, plus enough cardio to lose the belly fat

Stretching: Full Body - maintenance

Massage: Not primary

Also worth doing: Lose 5-10% of body weight if overweight, which raises testosterone more reliably than any supplement; 7-8 hours of sleep and a sleep-apnea check if you snore; limit alcohol; get the level measured properly - morning, fasted, twice - before treating a number

What the evidence says: Obesity-associated low testosterone is largely reversible: weight loss by lifestyle, drugs or surgery raises levels and restores the brain-testis signal. Resistance training raises testosterone acutely by up to about 30% and men who strength train often have a lower prevalence of low levels, but the durable effect comes from body composition and sleep - the number follows the belly, not the barbell.

The names above are the Targets qFIT tracks — the Muscle Guide explains what each one does, and Quick Add switches on the Exercises you already have.

The qFIT routine for this

Ready-made routineWeight, Cholesterol & Metabolic Health

qFIT already has this one built. It runs massage first, then stretching, then strength — the order that works on a body that is already sore — and every activity in it carries the reason it is there.

The button below opens your Checklist with this routine already selected, so instead of your whole list you land on just its Categories, Targets and Exercises, each with its checkbox, ready to tick as you work through them.

Have more than one problem? Tick yours under My Problems on My Profile and your Checklist's Routine list gains Recommended for my problems — every routine for the problems you picked, merged into one. Your picks stay private; that filter is the only thing they feed.

Get it checked if…

Low testosterone with headaches, visual change, loss of body hair, breast tissue growth, or infertility - endocrine review, it may be pituitary; never start testosterone without a proper diagnosis, it switches off fertility

And whatever the body part: chest pain or unusual breathlessness on exertion; a fever alongside the pain; unexplained weight loss; pain that is constant and unrelated to how you move; new numbness, weakness or loss of bladder or bowel control; or one calf that is swollen, warm and painful. Any of those, stop and get assessed.

How it usually goes

Where the loop is the cause, weight loss and resistance training raise testosterone measurably over three to six months, and many men return to a normal range without any medication. Replacement therapy is appropriate for genuine hypogonadism and it suppresses natural production and fertility, which makes the diagnosis worth getting right first. A single borderline reading in an overweight, poorly sleeping man is a reason to address the loop, not a reason to start treatment.

Prevalence basis: Endocrine Society and JCEM reviews of testosterone in men with obesity; population testosterone surveys

Others the same routine covers

These share the Weight, Cholesterol & Metabolic Health routine, so the work is the same. If one of them also sounds like you, that is a reason to expect more from it, not less.

This is general information, not a diagnosis, and it cannot examine you. If it matches you, use it to ask better questions of a clinician rather than to replace one.