Testogel is a prescription testosterone replacement therapy licensed exclusively for men with confirmed testosterone deficiency. Allowing your girlfriend to apply Testogel to your skin poses serious health risks through unintended testosterone transfer. Direct application by another person significantly increases the chance of hormonal exposure, which can cause virilisation in women—including voice deepening, excess hair growth, and menstrual disturbances—and may harm a developing foetus if she is pregnant. Children exposed to transferred testosterone may experience premature puberty and abnormal development. The MHRA emphasises that Testogel must be self-applied only, with application sites kept covered and washed before intimate contact to protect others from harm.

What Is Testogel and Who Should Use It

Testogel is a prescription-only testosterone replacement therapy (TRT) formulated as a clear, colourless hydroalcoholic gel containing testosterone. It is licensed in the UK by the MHRA for treating male hypogonadism—a condition where the testes produce insufficient testosterone, leading to symptoms such as reduced libido, fatigue, loss of muscle mass, mood disturbances, and erectile dysfunction.

The gel is applied once daily to clean, dry, intact skin. Application sites vary by formulation: Testogel 1% (50 mg/5 g) may be applied to the shoulders, upper arms, or abdomen, whereas Testogel 16.2 mg/g is licensed for application to the shoulders and upper arms only. Once applied, testosterone is absorbed transdermally (through the skin) into the bloodstream, providing steady hormone levels throughout the day. This method may reduce peak–trough variability compared with some intramuscular injection regimens and offers a convenient, non-invasive alternative for long-term hormone replacement.

Testogel is indicated exclusively for adult males with confirmed testosterone deficiency, diagnosed through clinical assessment and repeated early-morning serum testosterone measurements. NICE guidance emphasises that TRT should only be initiated after thorough evaluation, including exclusion of contraindications such as prostate or breast cancer, and assessment of cautions including severe cardiac, hepatic, or renal disease and untreated obstructive sleep apnoea.

It is not licensed for use in women or children, and there is no approved indication for performance enhancement, bodybuilding, or anti-ageing purposes in men with normal testosterone levels. Misuse or off-label application can lead to serious adverse effects. The product is designed for self-application by the patient only. Direct application by another person—particularly a partner—poses significant risks of unintended testosterone transfer, which can have harmful consequences for individuals not prescribed the medication.

Important safety considerations:

• Pregnancy risk: Testosterone transferred to a pregnant woman may cause virilisation of a female foetus. Pregnant women must avoid all contact with application sites.

• Monitoring: Before starting and during treatment, your GP will monitor prostate-specific antigen (PSA) and perform prostate examinations, and check haematocrit and haemoglobin levels, as testosterone can increase red blood cell production and may affect prostate health.

• Fertility: TRT can suppress sperm production. If you are planning a family, discuss this with your GP before starting treatment.

• Flammability: The gel is flammable until fully dry. Avoid naked flames, smoking, and other ignition sources during and immediately after application.

Risks of Testogel Transfer to Others

Unintended transfer of testosterone from Testogel to another person is a serious safety concern highlighted by the MHRA in Drug Safety Updates and product literature. When someone else applies the gel to your skin, or when skin-to-skin contact occurs before the gel has dried and the site is covered, testosterone can be transferred to that individual. This is particularly concerning for women (especially those who are pregnant), children, and adolescents, who may experience significant adverse effects from even small amounts of exogenous testosterone.

In women, unintended testosterone exposure can cause virilisation effects, including:

• Deepening of the voice (often irreversible)

• Increased body and facial hair growth (hirsutism)

• Acne and oily skin

• Menstrual irregularities or cessation

• Clitoral enlargement

• Male-pattern baldness

• Mood changes and aggression

In pregnant women, transferred testosterone may cause virilisation of a female foetus, leading to abnormal development of external genitalia and other masculinising effects. Pregnant women must avoid all contact with Testogel application sites.

In children and adolescents, testosterone transfer can lead to:

• Premature sexual development and precocious puberty

• Accelerated bone maturation and potential reduction in final adult height

• Behavioural changes and aggression

• Inappropriate development of secondary sexual characteristics

The risk is highest immediately after application, before the gel has fully dried. Direct application by a partner significantly increases transfer risk because it involves prolonged, direct skin contact during the application process itself, when testosterone concentration on the skin is at its peak. Even with hand washing afterwards, the person applying the gel may retain traces on their hands or forearms.

Case reports have documented virilisation in female partners and children following inadvertent testosterone transfer, some requiring medical intervention. The MHRA has issued specific warnings about this risk, emphasising the importance of patient-only application and protective measures: keep application sites covered with clothing once the gel has dried, and wash the application site with soap and water before any close physical or intimate contact with others.

Safe Application and Handling of Testogel

Proper application technique is essential to maximise therapeutic benefit and minimise transfer risk. The following evidence-based guidelines align with MHRA and manufacturer recommendations:

Application procedure:

• Apply the gel yourself—never allow another person to apply it for you

• Wash and dry your hands thoroughly before opening the sachet or tube

• Apply to clean, dry, intact skin on the licensed sites for your formulation: – Testogel 1% (50 mg/5 g): shoulders, upper arms, or abdomen – Testogel 16.2 mg/g: shoulders and upper arms only (not abdomen)

• Spread thinly and evenly over the recommended area

• Do not apply to the genital area

• Allow the gel to dry completely (3–5 minutes) before dressing

• The gel is flammable until dry—avoid naked flames, smoking, and other ignition sources during and immediately after application

• Wash your hands thoroughly with soap and water immediately after application

• Cover the application site with clothing once dry

Timing and precautions:

• Apply at the same time each day, ideally in the morning

• Wait before showering or bathing: for Testogel 1%, wait at least 1 hour; for other testosterone gels (e.g., Tostran, Testavan), waiting times may be longer (typically 2 hours or more)—check your product information leaflet

• Keep application sites covered with clothing to prevent transfer

• Wash the application site with soap and water before any close physical or intimate skin-to-skin contact with others

• Pregnant women must avoid all contact with application sites

Important safety measures:

• Never share your medication with others

• Store Testogel securely, out of reach of children and other household members

• Dispose of used sachets or tubes safely in household waste, ensuring children cannot access them

• Inform your GP or prescriber if you have concerns about application or potential transfer

If you require assistance with application due to physical limitations (e.g., shoulder mobility issues, arthritis), discuss alternative TRT formulations with your GP. UK-available options include:

• Long-acting intramuscular injection (testosterone undecanoate, Nebido): administered every 10–14 weeks

• Short-acting intramuscular injection (mixed testosterone esters, Sustanon): typically administered every 2–3 weeks

• Alternative transdermal gels (Tostran, Testavan): may have different application sites or characteristics

Your GP or endocrinologist can help identify the most suitable preparation for your circumstances, reducing the risk of transfer through assisted gel application.

What to Do If Accidental Testogel Transfer Occurs

If you suspect testosterone transfer has occurred to a partner, child, or other individual, prompt action is important. The following steps should be taken:

Immediate measures:

• Wash the affected skin area thoroughly with soap and water as soon as possible

• Remove any contaminated clothing and wash it

• If transfer occurred to a child, wash the affected area immediately and monitor for any unusual symptoms

• If the exposed person is pregnant, wash the area immediately and seek urgent advice from your GP, midwife, or NHS 111, informing them of the testosterone exposure

• Document when the exposure occurred and the approximate amount of contact

Monitoring for signs of testosterone exposure:

In women and girls, watch for:

• Voice changes or hoarseness

• Increased facial or body hair

• Acne or skin changes

• Menstrual irregularities

• Mood or behavioural changes

In children (particularly young boys), watch for:

• Premature development of pubic or body hair

• Genital enlargement

• Aggressive behaviour or mood changes

• Rapid growth or bone maturation

When to seek medical advice:

• Contact your GP or call NHS 111 if any signs of virilisation or inappropriate sexual development appear in someone exposed to Testogel

• For children showing signs of testosterone exposure, or for significant exposures even if asymptomatic, arrange a same-day GP assessment

• For pregnant women exposed to Testogel, seek urgent clinical advice from your GP, midwife, or NHS 111

• Inform the healthcare professional that testosterone gel transfer is suspected

• Your GP may arrange blood tests (serum testosterone levels) and refer to endocrinology if significant exposure is confirmed

Reporting adverse incidents:

If testosterone transfer causes harm, this should be reported via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk to help the MHRA monitor medication safety. Your prescriber can also submit a report on your behalf.

Prevention of future incidents is paramount. Review your application technique with your GP or practice nurse, ensure you understand the transfer risks, and consider whether Testogel remains the most appropriate TRT formulation for your circumstances. If transfer risk cannot be adequately managed, discuss alternative testosterone preparations with your healthcare provider.

Frequently Asked Questions