This article explains what treatment involves so that a conversation with your doctor starts from an informed position. It is not a recommendation, and nothing here can be acted on without a prescriber.
It is generally lifelong
This is the part most often skipped. Exogenous testosterone suppresses the body's own production through negative feedback on the pituitary. Stop after an extended period and natural production does not simply resume — it may take many months to recover, and in some men it does not fully return.
Starting treatment is therefore a decision with a long horizon, which is exactly why guidelines insist on confirming the diagnosis properly and excluding reversible causes first.
It suppresses fertility
The preparations
| Form | Typical schedule | Notes |
|---|---|---|
| Topical gel | Daily | Steady levels; requires care to avoid transferring to partners or children through skin contact |
| Short-acting injection | Every 2–3 weeks | Peaks and troughs; some men feel the decline before the next dose |
| Long-acting injection | Every 10–14 weeks | Stable levels, fewest administrations; slow to adjust if the dose is wrong |
The monitoring is not optional
Treatment comes with a fixed schedule of blood tests, typically at three and six months in the first year and annually thereafter. Three things are being watched:
- Haematocrit — testosterone stimulates red blood cell production. If it rises too high the blood thickens, and treatment is reduced, paused or managed by venesection.
- PSA — checked at baseline and monitored. Testosterone does not appear to cause prostate cancer, but it can accelerate an existing one, so a baseline before starting matters.
- Testosterone level itself — to confirm the dose is achieving a mid-range result rather than an excessive one.
What it does and does not fix
In men with genuine deficiency, the evidence supports improvement in libido, sexual function, mood, bone density and body composition. Improvements build over months, not days.
In men whose testosterone was never low, testosterone does not deliver those benefits. It does deliver the risks, plus suppression of natural production. This is the central reason the diagnosis has to be established before treatment starts — and the reason so much of the online market operates outside proper diagnosis.
The legal position in the UK
Testosterone is a prescription-only medicine and a Class C controlled substance. It can lawfully be supplied only by a registered pharmacy, against a prescription from an appropriate practitioner. Supplying it without one is a criminal offence, regardless of how the seller describes the product.
Anabolic steroids sold online as research chemicals, or from overseas sites willing to ship without a prescription, sit outside every safeguard described in this article — no diagnosis, no monitoring, no verified contents, no recourse. The monitoring described above is not bureaucracy; it is what catches the rising haematocrit before it becomes a clot.
Sources
BSSM guidelines on adult testosterone deficiency, 2022
Preparations, monitoring intervals, haematocrit and PSA thresholds, fertility counselling.
NICE Clinical Knowledge Summary: Hypogonadism — management
Primary care monitoring schedule and referral criteria.
Human Medicines Regulations 2012, reg. 214; Misuse of Drugs Act 1971
Prescription-only status and Class C controlled drug classification of testosterone in the UK.
