Should I use Testogel? This question requires careful medical assessment. Testogel is a prescription-only testosterone replacement therapy licensed in the UK exclusively for treating confirmed male hypogonadism—abnormally low testosterone levels verified by blood tests and clinical symptoms. It is not appropriate for men with normal testosterone seeking performance enhancement or general wellbeing. The decision to use Testogel must be made by a specialist or experienced GP following comprehensive evaluation, including two early morning testosterone measurements, physical examination, and assessment of cardiovascular and prostate health. This article explains who should use Testogel, its benefits and risks, and how to use it safely under medical supervision.

What Is Testogel and How Does It Work?

Testogel is a transdermal testosterone replacement therapy (TRT) licensed in the UK for treating male hypogonadism—a condition characterised by abnormally low testosterone levels. Two formulations are available: Testogel 1% (50 mg testosterone per 5 g sachet) and Testogel 16.2 mg/g (20.25 mg testosterone per pump actuation). Both are manufactured by Besins Healthcare and regulated by the Medicines and Healthcare products Regulatory Agency (MHRA).

The mechanism of action involves percutaneous absorption of exogenous testosterone through intact skin. Once applied to clean, dry skin—shoulders and upper arms for both formulations, with the abdomen also approved for the 1% sachets—the testosterone is gradually absorbed into the systemic circulation over several hours. This delivery method provides more stable daily testosterone levels compared with short-acting intramuscular injections, helping to maintain physiological concentrations throughout the day.

After absorption, testosterone undergoes peripheral conversion to its active metabolites: dihydrotestosterone (DHT) via 5-alpha-reductase and oestradiol via aromatase. These androgens bind to androgen receptors in target tissues, influencing protein synthesis, muscle mass, bone density, libido, mood, and secondary sexual characteristics.

Pharmacokinetic considerations include individual variation in skin permeability, application site, and the importance of allowing the gel to dry completely before dressing. Steady-state testosterone levels are typically achieved within a few days of daily application, though clinical benefits may take several weeks to manifest fully. Regular monitoring through blood tests is essential to ensure therapeutic levels are maintained.

Important safety information: Testogel is alcohol-based and flammable until completely dry. Avoid open flames, smoking, or sources of ignition until the gel has dried on your skin. Apply only to intact, healthy skin—never to broken, irritated, or damaged areas.

Who Should Use Testogel? Approved Indications in the UK

Testogel is licensed specifically for testosterone replacement in adult males with hypogonadism confirmed by clinical symptoms and biochemical evidence. According to NICE Clinical Knowledge Summaries and the British Society for Sexual Medicine, hypogonadism should be diagnosed based on two early morning serum testosterone measurements (ideally before 11:00 and fasting) taken on separate occasions, accompanied by relevant clinical features.

Diagnostic thresholds:

• Total testosterone below 8 nmol/L is usually consistent with hypogonadism

• Levels between 8–12 nmol/L are borderline and require assessment of symptoms, sex hormone-binding globulin (SHBG), and calculated free testosterone

• Levels above 12 nmol/L make hypogonadism unlikely

Clinical features warranting investigation include:

• Reduced libido and erectile dysfunction

• Decreased energy, fatigue, and reduced physical performance

• Loss of muscle mass and increased adiposity

• Mood disturbances, including depression and irritability

• Reduced bone mineral density or osteoporosis

• Hot flushes and sweating

Primary hypogonadism (testicular failure) and secondary hypogonadism (hypothalamic-pituitary dysfunction) are both appropriate indications. Causes include Klinefelter syndrome, chemotherapy, pituitary tumours, chronic illness, and age-related decline, though the latter requires careful assessment.

Baseline investigations should include luteinising hormone (LH), follicle-stimulating hormone (FSH), prolactin, SHBG, and iron studies to distinguish primary from secondary hypogonadism. Consider pituitary imaging if secondary hypogonadism is suspected, particularly with very low testosterone, elevated prolactin, or symptoms suggesting pituitary pathology. Referral to endocrinology is appropriate for secondary hypogonadism, very low testosterone levels, hyperprolactinaemia, pituitary mass symptoms, or fertility concerns.

Testogel is not appropriate for:

• Men with normal testosterone levels seeking performance enhancement

• Individuals with prostate cancer or breast cancer

• Men actively trying to conceive (testosterone suppresses spermatogenesis; alternative management should be considered)

Use with caution and specialist assessment in:

• Severe heart failure or recent cardiovascular events

• Untreated severe obstructive sleep apnoea

• Significant lower urinary tract symptoms or elevated prostate-specific antigen (PSA)

Before initiating treatment, comprehensive assessment should include digital rectal examination (DRE), PSA testing in men over 40, full blood count, lipid profile, liver function tests, and cardiovascular risk stratification. The decision to prescribe should be made by a specialist or experienced GP following thorough evaluation, not based solely on patient request or non-specific symptoms.

Potential Benefits and Risks of Testogel Treatment

When appropriately prescribed for confirmed hypogonadism, Testogel can deliver significant clinical benefits. Patients typically report improved libido and sexual function within 3–6 weeks, though maximal effects may require 6 months. Energy levels, mood, and sense of wellbeing often improve within the first few months. Body composition changes—including increased lean muscle mass and reduced fat mass—develop gradually over 12–24 months. Bone mineral density improvements occur more slowly, typically requiring 2–3 years of consistent therapy.

Evidence from randomised controlled trials demonstrates that testosterone replacement can improve quality of life scores, reduce depressive symptoms in hypogonadal men, and enhance physical function. However, these benefits are most pronounced in men with genuinely low testosterone; there is limited evidence supporting TRT in men with borderline or normal levels.

Common adverse effects (as defined in the Summary of Product Characteristics) include:

• Skin reactions at application sites (erythema, pruritus, irritation)

• Acne and oily skin due to increased sebaceous gland activity

• Polycythaemia (elevated haematocrit), requiring monitoring

• Headache

• Mood changes, including increased irritability

• Worsening of benign prostatic hyperplasia (BPH) symptoms

• Gynaecomastia (breast enlargement)

• Hair loss (male pattern baldness)

Serious but less common risks warrant careful consideration:

• Cardiovascular events: Evidence on cardiovascular risk remains inconclusive. The MHRA and European Medicines Agency advise that testosterone should be used with caution in men with severe cardiovascular disease, and individual cardiovascular risk should be assessed and monitored during treatment.

• Prostate concerns: Whilst testosterone does not cause prostate cancer, it may accelerate existing disease and can increase PSA levels; PSA and DRE monitoring are mandatory.

• Venous thromboembolism (VTE): Events have been reported; risk may be increased, particularly in the presence of polycythaemia or other VTE risk factors. Seek urgent medical attention for symptoms of deep vein thrombosis or pulmonary embolism.

• Sleep apnoea: May worsen existing obstructive sleep apnoea; specialist assessment is advised if this condition is present or suspected.

• Infertility: Suppression of gonadotropins reduces sperm production; avoid if trying to conceive.

Transfer risk is unique to transdermal preparations. Testosterone can transfer to partners or children through skin-to-skin contact before the gel has dried or if the application site is not covered, potentially causing virilisation in women and children. If unintended skin contact occurs, wash the affected area immediately with soap and water. This risk necessitates strict application protocols and covering treated areas with clothing once dry.

Reporting side effects: If you experience any side effects, talk to your doctor or pharmacist. You can also report suspected side effects directly via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or via the Yellow Card app. Reporting helps provide more information on the safety of medicines.

How to Use Testogel Safely and Effectively

Application technique is crucial for both efficacy and safety. Apply Testogel once daily, preferably in the morning. Dosing and titration differ by formulation:

• Testogel 1% sachets: Usual starting dose is 50 mg (one 5 g sachet) daily, adjusted based on clinical response and testosterone levels.

• Testogel 16.2 mg/g pump: Usual starting dose is 40.5 mg (two pump actuations) daily, adjusted as needed.

Dose adjustments should be made based on testosterone levels measured after initiation or dose changes, and clinical response.

Step-by-step application guidance:

1. Apply to clean, dry, intact skin on shoulders and upper arms (both formulations); the abdomen is also approved for Testogel 1% sachets only. Never apply to the genitals or broken/irritated skin.

2. Spread thinly over a large area to maximise absorption.

3. Wash hands thoroughly with soap and water immediately after application.

4. Allow the gel to dry completely (3–5 minutes) before dressing. The gel is flammable until dry—avoid open flames, smoking, or sources of ignition.

5. Cover the application site with clothing once dry to prevent transfer to others.

6. Avoid washing the application area for at least 6 hours (Testogel 1% sachets) or at least 2 hours (Testogel 16.2 mg/g pump).

7. Shower or bathe before anticipated skin-to-skin contact with others, particularly children or pregnant women.

Monitoring requirements align with British Society for Sexual Medicine and NICE guidance:

• Baseline: Testosterone (two early morning samples), full blood count (including haematocrit), PSA and DRE (men over 40), liver function tests, lipid profile, blood pressure.

• 3–6 months after starting or changing dose: Testosterone level, full blood count (haematocrit), PSA (if baseline elevated or symptoms), liver function, lipids.

• Annually thereafter: Testosterone, full blood count (haematocrit), PSA and DRE (as clinically appropriate), liver function, lipid profile, blood pressure.

Management of polycythaemia: If haematocrit exceeds 0.54 (54%), treatment should be withheld or the dose reduced until levels normalise, in line with specialist guidance.

When to seek urgent medical attention:

• Call 999 or attend A&E immediately for severe chest pain, sudden breathlessness, unilateral leg swelling or pain (possible VTE), or symptoms of stroke.

• Contact your GP urgently for:

– Worsening urinary symptoms

– Prolonged, painful erections (priapism)

– Significant mood changes, aggression, or depression

– Signs of virilisation in household contacts (deepening voice, excessive hair growth in women or children)

Legal and safety considerations: Testosterone is a prescription-only medicine and a controlled drug under UK law. Obtaining testosterone without a valid prescription or from unregulated sources may be illegal and is unsafe. Treatment should never be initiated or continued without proper medical supervision, biochemical confirmation of hypogonadism, and regular monitoring. Self-medication poses significant health risks.

References and further information:

• Electronic Medicines Compendium (EMC): Testogel 50 mg in 5 g gel and Testogel 16.2 mg/g transdermal gel Summary of Product Characteristics

• NICE Clinical Knowledge Summaries: Male hypogonadism

• British Society for Sexual Medicine: Guidelines on adult testosterone deficiency

• MHRA Drug Safety Updates: Testosterone and cardiovascular risk

• NHS website: Male hypogonadism overview

• MHRA Yellow Card Scheme: yellowcard.mhra.gov.uk

Frequently Asked Questions