Testogel is a widely prescribed transdermal testosterone replacement therapy (TRT) used to treat male hypogonadism in the UK. Understanding how long Testogel lasts in your system is essential for maintaining stable testosterone levels and achieving optimal symptom relief. After daily application, Testogel is absorbed through the skin over approximately 24 hours, with peak testosterone levels reached within 2 to 6 hours. Steady-state concentrations are typically achieved within 2 to 3 days of consistent use. If treatment is stopped, testosterone levels return to baseline within 2 to 3 days. This article explains the duration of action, factors affecting absorption, and practical guidance for safe, effective use in line with UK clinical standards.
Summary: Testogel lasts approximately 24 hours in your system after each daily application, with steady-state testosterone levels achieved within 2 to 3 days of consistent use.
- Testogel is a transdermal testosterone gel licensed in the UK for treating male hypogonadism, available in 1% and 1.62% formulations applied once daily.
- Peak serum testosterone concentrations occur 2 to 6 hours after application, with therapeutic effects developing gradually over 3 to 6 months.
- If treatment is stopped, testosterone levels return to baseline within 2 to 3 days as transdermal absorption ceases.
- Absorption is affected by skin condition, washing timing (wait 2–6 hours depending on formulation), and accidental skin-to-skin transfer to others.
- Regular monitoring of testosterone levels, haemoglobin, haematocrit, and prostate-specific antigen is required at 3–6 months and then annually.
- Apply Testogel at the same time daily, allow to dry fully (3–5 minutes), and wash hands immediately to prevent transfer to women and children.
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What Is Testogel and How Does It Work?
Testogel is a transdermal testosterone replacement therapy (TRT) licensed in the UK for the treatment of male hypogonadism—a condition characterised by insufficient testosterone production. It is available in two formulations: Testogel 50 mg/5 g (1% gel) and Testogel 16.2 mg/g (1.62% gel). Both are applied once daily to clean, dry, intact skin.
The application site depends on the formulation you are prescribed. Testogel 1% may be applied to the shoulders, upper arms, or abdomen. Testogel 1.62% should be applied only to the shoulders and upper arms. Never apply the gel to the genital area.
The active ingredient, testosterone, is absorbed through the skin into the bloodstream, where it exerts its physiological effects. Testosterone is an androgen hormone essential for the development and maintenance of male secondary sexual characteristics, muscle mass, bone density, libido, and overall wellbeing. In men with hypogonadism, low testosterone levels can lead to fatigue, reduced sexual function, mood disturbances, and decreased muscle strength.
Mechanism of action: Once absorbed, testosterone enters the systemic circulation and binds to androgen receptors in target tissues throughout the body. It is then converted in some tissues to dihydrotestosterone (DHT) or oestradiol, which mediate specific androgenic and oestrogenic effects respectively. The transdermal route provides a more consistent release of testosterone than intramuscular injections, reducing fluctuations in hormone levels and bypassing first-pass hepatic metabolism.
Testogel is typically prescribed following biochemical confirmation of hypogonadism—low serum testosterone on two separate early morning samples (ideally taken before 11 a.m.), alongside clinical symptoms. Luteinising hormone (LH) and follicle-stimulating hormone (FSH) levels may also be measured to classify the type of hypogonadism. The MHRA-approved product is designed to restore physiological testosterone levels, thereby alleviating symptoms and improving quality of life in affected men.
How Long Does Testogel Last in Your System?
The duration of action of Testogel relates to its absorption kinetics and how testosterone is maintained in the body. After application, testosterone is absorbed gradually through the skin over several hours. Peak serum testosterone concentrations are typically reached within 2 to 6 hours post-application, though this can vary between individuals.
Because Testogel is applied daily and provides continuous absorption over approximately 24 hours, steady-state testosterone levels are generally achieved within 2 to 3 days of regular use. This means that after a few days of consistent application, your body maintains relatively stable testosterone concentrations throughout the dosing interval.
What happens if you stop using Testogel? If you miss a dose or discontinue treatment, testosterone levels will begin to decline and typically return to baseline within 2 to 3 days, as the transdermal absorption ceases. Symptoms of hypogonadism may return within several days to weeks, depending on your baseline endogenous production.
Duration of therapeutic effect: While individual doses are absorbed and metabolised relatively quickly, the clinical effects of testosterone replacement—such as improvements in energy, mood, libido, and muscle mass—develop gradually over weeks to months. Symptom relief often begins within 3 to 6 weeks, with maximal benefits observed after 3 to 6 months of continuous therapy.
It is important to apply Testogel consistently at the same time each day to maintain stable hormone levels and optimise therapeutic outcomes. If you have concerns about missed doses or fluctuating symptoms, consult your GP or prescribing clinician for personalised advice.
References: emc SmPC Testogel 50 mg/5 g (1%) gel (pharmacokinetics); emc SmPC Testogel 16.2 mg/g (1.62%) gel (pharmacokinetics); NICE CKS: Testosterone deficiency in adult men.
Factors That Affect How Long Testogel Lasts
Several patient-specific and environmental factors can influence the absorption, metabolism, and duration of action of Testogel, leading to variability in serum testosterone levels and clinical response.
Skin condition and application site: The integrity and thickness of the skin at the application site significantly affect absorption. Damaged, inflamed, or excessively hairy skin may reduce or alter absorption. The recommended sites—shoulders, upper arms, and (for Testogel 1% only) abdomen—are chosen for their consistent absorption characteristics. Rotating application sites can help prevent local skin irritation.
Washing and physical activity: The time you must wait before washing or swimming depends on your formulation. For Testogel 1%, wait at least 6 hours after application. For Testogel 1.62%, the minimum interval is typically 2 hours. Showering or swimming before these times can reduce the amount of testosterone absorbed, as the gel may be washed off. Similarly, vigorous exercise or excessive sweating shortly after application may affect absorption.
Skin-to-skin contact and accidental transfer: Testosterone can be transferred to others through direct skin contact, particularly to women (including pregnant women) and children, which can cause unwanted androgenic effects. To prevent transfer:
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Allow the gel to dry fully (3 to 5 minutes) before dressing.
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Cover the application site with clothing once dry.
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Wash your hands thoroughly with soap and water immediately after application.
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Avoid skin-to-skin contact with others at the application site until you have washed it.
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If accidental transfer is suspected (e.g., a partner or child touches the application site), wash the exposed skin immediately with soap and water and seek medical advice, especially if the exposed person is pregnant or a child.
Body composition and metabolism: Men with higher body fat percentages may experience altered testosterone metabolism, as adipose tissue contains aromatase enzyme, which converts testosterone to oestradiol. Liver function also plays a role in testosterone metabolism, though this is less relevant with transdermal administration than with oral formulations.
Individual variability: Factors such as sex hormone-binding globulin (SHBG) levels and androgen receptor sensitivity may influence how testosterone is distributed and utilised in your body. These considerations can affect the interpretation of blood test results and clinical response.
Monitoring: Regular monitoring of serum testosterone levels, typically 3 to 6 months after initiation and then at least annually, helps ensure therapeutic levels are maintained. In the UK, monitoring also includes:
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Haemoglobin and haematocrit (Hb/Hct): Testosterone can stimulate red blood cell production. Treatment should be held if haematocrit exceeds 54%.
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Prostate-specific antigen (PSA) and prostate assessment: Baseline and periodic checks are recommended, particularly in men over 50 or those at higher risk.
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Blood pressure and symptom review.
Your prescriber will use your local laboratory reference ranges and aim for mid-normal testosterone levels to balance efficacy and safety.
References: emc SmPC Testogel 50 mg/5 g (1%) gel (washing/transfer advice); emc SmPC Testogel 16.2 mg/g (1.62%) gel (washing/transfer advice); NICE CKS: Testosterone deficiency (monitoring recommendations); BNF: Testosterone (topical).
When to Apply Testogel for Consistent Testosterone Levels
To achieve stable, physiological testosterone levels, Testogel should be applied once daily at approximately the same time each day, ideally in the morning. Morning application is often recommended to align with the natural circadian rhythm of testosterone secretion, which peaks in the early morning hours in healthy men. However, follow your prescriber's specific instructions for your formulation.
Application technique:
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Apply the gel to clean, dry, intact skin on the shoulders and upper arms (both formulations) or abdomen (Testogel 1% only). Never apply to the genital area.
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Spread the gel as a thin layer over the recommended application area.
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Allow the gel to dry fully for 3 to 5 minutes before dressing.
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Important safety warning: Testogel is flammable until dry. Avoid open flames, smoking, or sources of ignition until the gel has completely dried.
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Wash your hands thoroughly with soap and water immediately after application to prevent accidental transfer to others.
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Avoid washing, showering, or swimming for at least 6 hours (Testogel 1%) or 2 hours (Testogel 1.62%) after application.
Consistency is key: Daily application at the same time helps maintain steady-state testosterone levels and reduces the risk of symptom fluctuation. If you miss a dose, apply it as soon as you remember on the same day. If it is almost time for your next dose, skip the missed dose—do not apply a double dose to compensate.
Monitoring and adjustment: Your prescriber will monitor your serum testosterone levels periodically, usually via a blood test taken in the morning before you apply your dose. The aim is to achieve levels within the mid-normal range for your local laboratory reference. Dose adjustments may be necessary based on these results and your clinical response.
In addition to testosterone levels, your prescriber will monitor:
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Haemoglobin and haematocrit (Hb/Hct): at baseline, 3–6 months, and then at least annually. Treatment should be held if haematocrit exceeds 54%.
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Prostate-specific antigen (PSA) and prostate assessment: at baseline and periodically, according to age and risk factors.
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Blood pressure and overall symptom review.
When to seek advice: Contact your GP or specialist if you experience:
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Signs of inadequate testosterone replacement (persistent fatigue, low libido, mood changes).
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Symptoms suggestive of excessive testosterone (acne, aggression, fluid retention, or breast enlargement).
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Skin irritation at the application site.
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Concerns about accidental transfer to household members, particularly pregnant women or children.
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Symptoms that may suggest polycythaemia (e.g., headaches, dizziness, visual disturbances) or thromboembolic events (e.g., chest pain, shortness of breath, leg swelling or pain).
Regular follow-up in line with NICE and UK specialist guidance ensures safe and effective long-term testosterone replacement therapy.
Reporting side effects: If you experience any side effects, talk to your doctor or pharmacist. You can also report side effects directly via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or search for MHRA Yellow Card in the Google Play or Apple App Store.
References: emc SmPC Testogel 50 mg/5 g (1%) gel; emc SmPC Testogel 16.2 mg/g (1.62%) gel; NICE CKS: Testosterone deficiency in adult men; BNF: Testosterone (topical) – monitoring and precautions; Society for Endocrinology UK/BSSM guidance on male hypogonadism.
Frequently Asked Questions
How long does Testogel stay in your body after you apply it?
Testogel is absorbed over approximately 24 hours after each application, with peak testosterone levels reached within 2 to 6 hours. If you stop using Testogel, testosterone levels return to baseline within 2 to 3 days as the transdermal absorption ceases.
What happens if I miss a dose of Testogel?
If you miss a dose of 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—never apply a double dose to compensate.
How long after applying Testogel can I shower or swim?
For Testogel 1%, wait at least 6 hours before showering or swimming. For Testogel 1.62%, the minimum waiting time is typically 2 hours. Washing before these times can reduce testosterone absorption as the gel may be washed off.
Can Testogel transfer to my partner or children through skin contact?
Yes, testosterone can transfer to others through direct skin-to-skin contact, potentially causing unwanted androgenic effects in women and children. To prevent this, allow the gel to dry fully, cover the application site with clothing, wash your hands immediately after application, and avoid skin contact at the site until you have washed it.
How does Testogel compare to testosterone injections for hypogonadism?
Testogel provides more consistent testosterone levels than intramuscular injections, reducing hormone fluctuations and avoiding the peaks and troughs associated with injectable formulations. However, it requires daily application and carries a risk of accidental transfer to others, whereas injections are typically administered every 2 to 12 weeks depending on the formulation.
How do I get a prescription for Testogel in the UK?
Testogel is a prescription-only medicine requiring biochemical confirmation of hypogonadism—low serum testosterone on two separate early morning blood samples (before 11 a.m.), alongside clinical symptoms. Your GP or specialist will assess your results, perform a clinical examination, and initiate treatment if appropriate, with regular monitoring thereafter.
The health-related content published on this site is based on credible scientific sources and is periodically reviewed to ensure accuracy and relevance. Although we aim to reflect the most current medical knowledge, the material is meant for general education and awareness only.
The information on this site is not a substitute for professional medical advice. For any health concerns, please speak with a qualified medical professional. By using this information, you acknowledge responsibility for any decisions made and understand we are not liable for any consequences that may result.
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