Is testosterone treatment permanent? Many men prescribed testosterone replacement therapy (TRT) in the UK wonder whether this treatment is a lifelong commitment. Testosterone replacement therapy is not a permanent cure for low testosterone; rather, it is an ongoing hormone replacement that requires continued administration to maintain therapeutic levels. When TRT is stopped, testosterone levels typically return to pre-treatment baseline within weeks to months. The reversibility and duration of treatment depend significantly on the underlying cause of hypogonadism, individual physiology, and treatment goals. This article explores how TRT works, what happens when treatment stops, and NHS guidance on treatment duration.

Understanding Testosterone Replacement Therapy in the UK

Testosterone replacement therapy (TRT) is a medical treatment prescribed to men diagnosed with hypogonadism—a condition where the testes produce insufficient testosterone. In the UK, TRT is regulated by the Medicines and Healthcare products Regulatory Agency (MHRA) and prescribed according to guidelines from the National Institute for Health and Care Excellence (NICE) and specialist bodies like the British Society for Sexual Medicine.

The primary indications for TRT include:

• Confirmed low serum testosterone levels (typically requiring two early-morning samples, with levels below the laboratory's reference range or in the borderline range of 8-12 nmol/L with symptoms)

• Clinical symptoms such as reduced libido, erectile dysfunction, fatigue, mood disturbances, and loss of muscle mass

• Appropriate investigation to determine the cause (primary vs secondary hypogonadism)

TRT works by supplementing the body's natural testosterone through various delivery methods. In the UK, the most commonly prescribed formulations include transdermal gels (such as Testogel, Tostran, and Testavan) and intramuscular injections (testosterone undecanoate [Nebido] or shorter-acting mixed esters like Sustanon). The mechanism of action involves binding to androgen receptors throughout the body, influencing protein synthesis, bone density, red blood cell production, and sexual function. Treatment aims to restore testosterone levels to the mid-normal physiological range, thereby alleviating symptoms and improving quality of life.

Before initiating TRT, clinicians must conduct thorough assessments including prostate examination, prostate-specific antigen (PSA) testing, full blood count, luteinising hormone (LH), follicle-stimulating hormone (FSH), prolactin, and cardiovascular risk evaluation. Contraindications include proven or suspected prostate or male breast cancer, while caution is advised in men with severe cardiac, hepatic or renal disease, and untreated obstructive sleep apnoea. The decision to commence TRT should be made collaboratively between patient and clinician, with clear discussion of benefits, risks, and the expected duration of treatment.

Is Testosterone Treatment Permanent or Reversible?

Testosterone replacement therapy is not a permanent treatment in the sense that it does not cure the underlying cause of hypogonadism. Rather, it is a form of hormone replacement that requires ongoing administration to maintain therapeutic testosterone levels. When TRT is discontinued, testosterone levels typically return to pre-treatment baseline within weeks to months, depending on the formulation used and individual physiology.

The reversibility of TRT depends significantly on the underlying cause of low testosterone. In cases of primary hypogonadism (testicular failure due to genetic conditions, chemotherapy, or trauma), the testes cannot produce adequate testosterone independently, and stopping TRT will result in a return to hypogonadal levels. Conversely, in secondary hypogonadism (hypothalamic-pituitary dysfunction), there may be potential for recovery of natural testosterone production after cessation, particularly if the underlying cause is addressed—such as weight loss in obesity-related hypogonadism or treatment of hyperprolactinaemia.

It is important to note that TRT suppresses the hypothalamic-pituitary-gonadal (HPG) axis through negative feedback mechanisms. Exogenous testosterone signals the pituitary gland to reduce production of luteinising hormone (LH) and follicle-stimulating hormone (FSH), which in turn decreases endogenous testosterone production and spermatogenesis. This suppression is generally reversible upon cessation of therapeutic TRT, though recovery time varies between individuals—ranging from several months to over a year in some cases. Most men on physiological replacement doses recover HPG axis function after cessation, though the timeline varies individually.

Men considering future fertility should discuss this with their healthcare provider before starting TRT, as alternative treatments may be more appropriate. In the UK, specialist-led alternatives for men wishing to preserve fertility include human chorionic gonadotrophin (hCG) with or without FSH, or off-label use of clomifene, depending on whether the cause is primary or secondary hypogonadism.

What Happens When You Stop Testosterone Treatment

Discontinuing testosterone replacement therapy leads to a gradual decline in serum testosterone levels, with the rate of decline depending on the formulation used. Short-acting preparations such as transdermal gels clear within 24–48 hours, whilst long-acting intramuscular injections (e.g., testosterone undecanoate) may maintain elevated levels for several weeks. As testosterone levels fall, patients typically experience a recurrence of hypogonadal symptoms.

Common symptoms following TRT cessation include:

• Fatigue and reduced energy levels

• Decreased libido and erectile dysfunction

• Mood changes, including low mood or irritability

• Loss of muscle mass and strength

• Reduced sense of wellbeing

• Hot flushes (in some individuals)

The HPG axis gradually recovers after stopping TRT, though this process is not immediate. The pituitary gland must resume production of LH and FSH, which then stimulate the testes to produce testosterone. This recovery period can be uncomfortable, and some men experience a temporary worsening of symptoms during the transition. Recovery time varies between individuals, with most men on therapeutic doses eventually regaining their baseline function.

Patients should discuss discontinuation with their prescriber rather than stopping treatment without medical supervision. If discontinuation is planned—whether due to side effects, fertility concerns, or patient preference—a structured approach with regular monitoring is essential. Your GP or endocrinologist can provide guidance on managing withdrawal symptoms and assessing HPG axis recovery through serial hormone measurements (typically early-morning testosterone, LH and FSH at 6-12 week intervals). If symptoms become severe or persistent, contact your healthcare provider promptly. In some cases, specialist-initiated treatments to stimulate natural testosterone production may be considered during the recovery phase.

Long-Term Effects and Considerations of TRT

Long-term testosterone replacement therapy requires careful monitoring due to potential adverse effects and the need for ongoing assessment of treatment efficacy. When appropriately prescribed and monitored, TRT can provide sustained benefits including improved sexual function, mood, energy levels, and maintenance of bone density and muscle mass. However, indefinite treatment necessitates regular clinical review.

Key long-term considerations include:

Cardiovascular effects: The relationship between TRT and cardiovascular risk remains an area of ongoing research. Current evidence suggests that maintaining testosterone within the physiological range does not significantly increase cardiovascular risk in most men, though the MHRA advises closer monitoring in men with pre-existing cardiovascular disease.

Prostate health: There is no evidence that TRT increases the incidence of prostate cancer, but it may stimulate growth of existing or occult prostate cancer. Regular monitoring includes digital rectal examination and PSA testing. Consider referral if PSA rises by more than 1.4 ng/mL within 12 months, exceeds 4.0 ng/mL, or if digital rectal examination is abnormal, in line with NICE guidance (NG12).

Haematological effects: Testosterone stimulates erythropoiesis (red blood cell production), which can lead to polycythaemia (elevated haematocrit). This increases blood viscosity and thrombotic risk. If haematocrit reaches or exceeds 0.54, treatment may need to be paused or reduced, and underlying factors (e.g., sleep apnoea, smoking) addressed. Venesection may be required in some cases.

Fertility: TRT typically results in oligospermia or azoospermia (reduced or absent sperm production). Men wishing to preserve fertility should consider sperm banking before commencing treatment or discuss alternative therapies with a specialist.

Other adverse effects: These may include acne, gynaecomastia, fluid retention, worsening of sleep apnoea, application site reactions with gels, and pain or pulmonary oil microembolism with injections. Patients using testosterone gel must take precautions to avoid transferring the medication to women or children through skin contact.

Bone density: Long-term TRT helps maintain bone mineral density, reducing osteoporosis risk—a significant benefit in hypogonadal men. Conversely, stopping treatment may accelerate bone loss if testosterone levels remain low.

If you experience suspected adverse effects from TRT, report them via the MHRA Yellow Card scheme.

NHS Guidelines on Testosterone Therapy Duration

The NHS follows guidance from NICE and specialist endocrine societies regarding the duration and monitoring of testosterone replacement therapy. There is no predetermined endpoint for TRT; treatment duration is individualised based on the underlying cause of hypogonadism, treatment response, patient preference, and the presence of adverse effects.

For men with permanent hypogonadism (such as Klinefelter syndrome, bilateral orchidectomy, or testicular failure from chemotherapy), TRT is typically lifelong, provided it remains well-tolerated and beneficial. These patients require ongoing monitoring but are unlikely to regain natural testosterone production.

In cases of potentially reversible hypogonadism—such as that associated with obesity, metabolic syndrome, or certain medications—treatment duration may be finite. The underlying causes should be addressed alongside TRT. In these cases, specialists may consider a supervised trial off treatment (typically 3–6 months) with subsequent hormone measurement to determine whether natural testosterone production has recovered sufficiently.

NHS monitoring protocols typically include:

• Clinical assessment of symptoms and treatment response at 3 months, then 6–12 monthly

• Testosterone level measurement at 3 months after initiation (timed appropriately for the formulation—trough levels for injections, morning levels for gels), then 6–12 monthly

• PSA and digital rectal examination at baseline, 3–6 months, then annually (more frequently if abnormalities detected)

• Full blood count monitoring for polycythaemia at the same intervals

• Bone density scanning in high-risk individuals

Patients should have annual reviews with their GP or specialist to discuss treatment continuation, assess for adverse effects, and ensure ongoing clinical need. If you experience concerning symptoms such as chest pain, leg swelling, difficulty urinating, or significant mood changes whilst on TRT, contact your GP promptly. Treatment should only be continued when the benefits clearly outweigh the risks, and this balance should be reassessed regularly throughout the treatment course.

Frequently Asked Questions