Testogel is a transdermal testosterone replacement therapy prescribed for men with confirmed hypogonadism—a condition where the body produces insufficient testosterone. Applied daily to the skin, Testogel delivers a steady dose of testosterone, helping to restore normal hormone levels and alleviate symptoms such as fatigue, reduced libido, and mood disturbances. Correct application technique, appropriate dosing, and regular monitoring are essential for safe and effective treatment. This guide explains how to use Testogel for men, covering application methods, dosage, safety precautions, and when to seek medical advice.

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 where the testes produce insufficient testosterone. It is available in two formulations: Testogel 1% (50 mg per 5 g sachet) and Testogel 16.2 mg/g (metered-dose pump). Both contain testosterone as the active ingredient, formulated as a clear or slightly opalescent gel.

The gel is applied directly to the skin. Testogel 1% sachets may be applied to the shoulders, upper arms, or abdomen, whereas Testogel 16.2 mg/g pump should be applied only to the shoulders and upper arms. Once applied, testosterone is absorbed through the skin into the bloodstream over several hours. This transdermal delivery system provides a steady release of testosterone, helping to restore physiological levels in men with confirmed testosterone deficiency. Unlike intramuscular injections, which can cause peaks and troughs in hormone levels, Testogel offers more consistent plasma concentrations throughout the day.

Mechanism of action: Testosterone is the primary male sex hormone (androgen) responsible for the development and maintenance of male secondary sexual characteristics, muscle mass, bone density, libido, and overall wellbeing. In hypogonadal men, low testosterone can lead to fatigue, reduced sexual function, mood disturbances, and decreased muscle strength. By supplementing endogenous testosterone, Testogel helps alleviate these symptoms.

Before starting Testogel: Men should have their testosterone deficiency confirmed through blood tests—typically two early-morning samples showing low serum testosterone—and a clinical assessment by their GP or endocrinologist. Baseline assessments should include prostate-specific antigen (PSA) testing and a full blood count (FBC) to rule out contraindications and establish monitoring baselines. TRT should only be prescribed when there is both biochemical and clinical evidence of hypogonadism.

Contraindications: Testogel must not be used in men with prostate cancer, male breast cancer, or suspected prostate or breast malignancy. It should be used with caution in men with severe cardiac, hepatic, or renal disease.

Important safety information: Testosterone replacement therapy can suppress spermatogenesis and may impair fertility. Men planning to father children should discuss this with their doctor before starting treatment. The MHRA and European Medicines Agency (EMA) have reviewed the cardiovascular safety of testosterone products and concluded that there is no consistent evidence of increased cardiovascular risk overall; however, TRT should be used only in men with confirmed hypogonadism and appropriate monitoring should be maintained.

How to Apply Testogel Correctly: Step-by-Step Guide

Correct application of Testogel is essential to ensure optimal absorption and minimise the risk of transferring testosterone to others. The application technique differs slightly between formulations.

Preparation:

• Wash and dry your hands thoroughly before opening the sachet or using the pump.

• Ensure the application site is clean, dry, and free from cuts, irritation, or broken skin.

• Do not apply Testogel to the genital area, as this increases the risk of local irritation and is not an approved application site.

Application sites by formulation:

• Testogel 1% sachets: Apply to the shoulders, upper arms, or abdomen.

• Testogel 16.2 mg/g pump: Apply only to the shoulders and upper arms (not the abdomen).

1. Application process:
2. Open the sachet carefully, or prime the pump if using a new dispenser (typically 3 actuations to waste for the 16.2 mg/g pump, as per the manufacturer's instructions).
3. Squeeze the gel onto one palm or directly onto the application area.
4. Spread thinly over the recommended application sites as directed for your formulation.
5. Allow to dry for at least 3–5 minutes before dressing. The gel dries quickly and should not leave a visible residue.
6. Cover the application site with clothing once dry.
7. Wash your hands immediately after application with soap and water to prevent accidental transfer.

Important safety measures to prevent transfer to others:

• Avoid skin-to-skin contact with others (especially women, children, and pregnant women) until after washing or for the recommended time after application: – Testogel 1% sachets: Wait at least 6 hours before showering, bathing, or swimming, and avoid close skin contact during this time. – Testogel 16.2 mg/g pump: Wait at least 2 hours before showering, bathing, or swimming, and avoid close skin contact during this time.

• Wash the application site with soap and water before any situation where close skin-to-skin contact is anticipated.

• If accidental contact occurs, the other person (especially women or children) should immediately wash the exposed skin thoroughly with soap and water.

• Shower or bathe after the recommended interval to ensure adequate absorption; washing earlier may reduce effectiveness.

Consistency in application technique and timing helps maintain stable testosterone levels and improves treatment outcomes.

Dosage and When to Use Testogel

Standard dosing by formulation:

• Testogel 1% sachets: The usual starting dose is 50 mg of testosterone daily (one 5 g sachet). Your doctor may adjust this dose based on blood testosterone levels, typically ranging from 25 mg to 100 mg daily.

• Testogel 16.2 mg/g pump: The usual starting dose is 40.5 mg of testosterone daily (2 pump actuations, each delivering 20.25 mg). Your doctor may adjust this dose, typically ranging from 20.25 mg (1 actuation) to 81 mg (4 actuations) daily.

Your doctor will adjust your dose based on blood testosterone levels measured after starting treatment and periodically thereafter. The target is to achieve testosterone levels within the normal physiological range (usually 10–30 nmol/L, though reference ranges vary slightly between laboratories). Blood samples should be taken at a consistent time relative to your daily application and using the same laboratory for accurate comparison.

Timing of application: Testogel should be applied once daily, preferably at the same time each day—most commonly in the morning. This mimics the natural circadian rhythm of testosterone production, which peaks in the early morning. Consistency in timing helps maintain stable hormone levels and supports adherence to treatment.

Monitoring and dose adjustment: After starting Testogel, your GP or specialist will arrange blood tests to check your testosterone levels, typically 2–4 weeks after initiation and then every 3–6 months once stable. Regular monitoring should include:

• Serum testosterone levels

• Full blood count (FBC) and haematocrit to detect polycythaemia (increased red blood cell count)

• Prostate-specific antigen (PSA) testing, particularly in men over 40 or those at higher risk of prostate disease

• Clinical review of symptoms and side effects

If your haematocrit rises above 54%, your doctor may temporarily stop treatment or reduce your dose and investigate the cause. British Society for Sexual Medicine (BSSM) and Society for Endocrinology guidance recommend at least annual monitoring once treatment is stable.

What to do if you miss a dose: If you forget to apply Testogel, apply it as soon as you remember on the same day. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule. Do not apply a double dose to make up for a missed application.

Duration of treatment: Testosterone replacement is usually a long-term therapy for men with persistent hypogonadism. Regular follow-up with your healthcare provider is essential to monitor efficacy, adjust dosing, and screen for potential complications.

Common Side Effects and When to Seek Medical Advice

Like all medicines, Testogel can cause side effects, although not everyone experiences them. Understanding potential adverse effects helps you recognise when to seek medical advice.

Common side effects (affecting up to 1 in 10 men) include:

• Skin reactions at the application site: redness, itching, dry skin, or acne. These are usually mild and resolve with continued use. Rotating application sites within the approved areas may help.

• Headache and mood changes, including increased aggression or irritability in some men.

• Increased haematocrit (red blood cell concentration), which may require dose adjustment or temporary cessation if levels become too high.

• Prostate changes: Testogel can stimulate prostate growth. Regular PSA monitoring is essential, particularly in older men.

Less common but important side effects include:

• Gynaecomastia (breast enlargement or tenderness)

• Fluid retention and weight gain

• Sleep disturbances, including worsening of sleep apnoea

• Hair loss or increased body hair growth

• Suppression of spermatogenesis and testicular atrophy, which may affect fertility

When to seek urgent medical advice:

Call 999 or go to A&E immediately if you experience:

• Severe chest pain, shortness of breath, or symptoms suggestive of a heart attack or stroke

• Prolonged or painful erections (priapism) lasting more than 4 hours—this requires emergency treatment

• Severe difficulty breathing or signs of a severe allergic reaction (swelling of the face or throat)

Contact your GP or call NHS 111 if you experience:

• Signs of an allergic reaction: rash, itching, or mild swelling

• Significant mood changes, depression, or suicidal thoughts

• Yellowing of the skin or eyes (jaundice), which may indicate liver problems (rare with transdermal testosterone)

• New or worsening symptoms that concern you

Transfer to others: Be aware that testosterone can transfer to partners, children, or pregnant women through skin contact. If a woman or child develops signs of testosterone exposure (acne, increased body hair, behavioural changes, or in children, early sexual development), seek medical advice immediately and review your application technique. Always cover the application site with clothing once dry, and if accidental contact occurs, wash the exposed skin of the other person immediately with soap and water.

Reporting side effects: You can report suspected side effects via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or by searching for MHRA Yellow Card in the Google Play or Apple App Store. Reporting helps improve the safety information available about medicines.

Regular monitoring by your healthcare team, including blood tests for testosterone, haematocrit, PSA, and clinical review, helps detect and manage side effects early. Always report new or worsening symptoms to your GP, and attend all scheduled follow-up appointments to ensure safe and effective treatment.

Frequently Asked Questions