Testogel is a prescription-only transdermal testosterone replacement therapy licensed in the UK for treating male hypogonadism, a condition where the testes produce insufficient testosterone. Applied daily as a gel to the shoulders or upper arms, it restores physiological testosterone levels, helping to alleviate symptoms such as reduced libido, fatigue, loss of muscle mass, and mood disturbances. Diagnosis requires biochemical confirmation through repeated early-morning testosterone measurements alongside clinical symptoms. Treatment must be initiated and monitored by a specialist, typically an endocrinologist or urologist, with ongoing care often managed in primary care under shared-care agreements. Proper application technique and regular monitoring are essential to ensure safety and effectiveness.
Summary: Testogel is used to treat male hypogonadism, a condition characterised by insufficient testosterone production confirmed through biochemical testing and clinical symptoms.
- Testogel is a transdermal testosterone gel applied once daily to the shoulders or upper arms, bypassing first-pass hepatic metabolism.
- It is licensed exclusively for adult males with confirmed hypogonadism, not for age-related testosterone decline or performance enhancement.
- Diagnosis requires at least two early-morning serum testosterone measurements below normal range plus clinical symptoms such as reduced libido, fatigue, and loss of muscle mass.
- Contraindications include known or suspected prostate or breast cancer, and it must never be used by women or children.
- Regular monitoring of testosterone levels, haematocrit, PSA, and cardiovascular risk factors is essential throughout treatment.
- Preventing testosterone transfer to others, particularly women and children, requires careful application technique and covering treated skin with clothing.
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What Is Testogel and How Does It Work?
Testogel is a transdermal testosterone replacement therapy (TRT) available as a clear, colourless gel containing testosterone as the active ingredient. It is licensed in the UK by the Medicines and Healthcare products Regulatory Agency (MHRA) for the treatment of male hypogonadism, a condition characterised by insufficient testosterone production. The gel is applied once daily, in the morning, directly to clean, dry, intact skin on the shoulders and/or upper arms (for the UK-marketed Testogel 16.2 mg/g formulation), where it is absorbed into the bloodstream.
The mechanism of action involves transdermal absorption of testosterone through the skin, bypassing first-pass hepatic metabolism. Once absorbed, testosterone enters systemic circulation and binds to androgen receptors throughout the body. This exogenous testosterone supplementation restores physiological levels of the hormone, which plays crucial roles in maintaining muscle mass, bone density, libido, mood regulation, and secondary sexual characteristics.
Testosterone levels typically begin to rise within hours of application, with steady-state concentrations achieved after several days of consistent use. The gel formulation provides more stable serum testosterone levels and fewer peaks and troughs throughout the day compared with some other forms of testosterone replacement, such as intramuscular injections. This pharmacokinetic profile contributes to more consistent symptom control and potentially fewer fluctuations in mood and energy levels.
It is important to note that Testogel is a prescription-only medicine in the UK and should only be used under the supervision of a qualified healthcare professional. Diagnosis and initiation are typically undertaken by a specialist (such as an endocrinologist or urologist), though ongoing prescribing and monitoring may be managed in primary care under shared-care agreements.
Medical Conditions Treated with Testogel
Testogel is indicated for the treatment of male hypogonadism, also known as testosterone deficiency syndrome. This condition occurs when the testes produce insufficient amounts of testosterone, either due to primary testicular failure (primary hypogonadism) or dysfunction of the hypothalamic-pituitary axis (secondary hypogonadism). Primary causes include Klinefelter syndrome, testicular injury, chemotherapy, or radiation therapy, whilst secondary causes may involve pituitary tumours, certain medications, or chronic illnesses.
The clinical presentation of hypogonadism varies but commonly includes:
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Reduced libido and erectile dysfunction
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Fatigue and decreased energy levels
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Loss of muscle mass and strength
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Increased body fat, particularly abdominal adiposity
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Decreased bone mineral density (osteoporosis)
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Mood disturbances, including depression and irritability
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Reduced facial and body hair growth
According to UK guidance from the Society for Endocrinology and the British Society for Sexual Medicine (BSSM), testosterone replacement should only be initiated after biochemical confirmation of hypogonadism through repeated early-morning serum testosterone measurements (on at least two separate occasions) showing levels below the normal reference range, together with clinical symptoms. Additional investigations may include measurement of luteinising hormone (LH) and follicle-stimulating hormone (FSH) to distinguish primary from secondary hypogonadism, sex hormone-binding globulin (SHBG) and calculated free testosterone if borderline, and prolactin if secondary hypogonadism is suspected. Reversible causes (such as acute illness, obesity, or certain medications) should be excluded before starting treatment. Symptoms alone are insufficient for diagnosis, as they are non-specific and may be attributable to other medical conditions.
It is crucial to understand that Testogel is not recommended for age-related decline in testosterone (sometimes called 'andropause' or late-onset hypogonadism) in the absence of pathological hypogonadism. Additionally, Testogel should not be used to enhance athletic performance or bodybuilding, as such use is both unlicensed and potentially harmful.
Who Can Use Testogel: Eligibility and Prescribing Criteria
Testogel is licensed exclusively for adult males with confirmed hypogonadism. Before prescribing, clinicians must establish both biochemical evidence (consistently low serum testosterone levels on at least two separate early-morning samples) and clinical symptoms consistent with testosterone deficiency. The diagnosis should be made by a specialist with appropriate expertise, typically an endocrinologist or urologist, though ongoing prescribing and monitoring may be undertaken in primary care under shared-care protocols.
Contraindications to Testogel use include:
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Known or suspected prostate cancer or breast cancer
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Hypersensitivity to testosterone or any excipients in the formulation
Testogel is not suitable for women or children and should never be used in these populations due to the risk of virilisation and other serious adverse effects. Pregnant women must avoid any contact with application sites; if contact occurs, the area should be washed immediately with soap and water.
Cautions requiring careful assessment and monitoring include:
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Severe heart failure or other significant cardiovascular disease
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Untreated severe sleep apnoea
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Polycythaemia (elevated red blood cell count) or haematocrit above 0.54 (54%); treatment should be withheld or discontinued if haematocrit exceeds this threshold
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Pre-existing epilepsy, migraine, or conditions that may be exacerbated by fluid retention
Before initiating treatment, patients should undergo comprehensive baseline investigations, including digital rectal examination (DRE) and prostate-specific antigen (PSA) testing in accordance with the Summary of Product Characteristics (SmPC) and local protocols. Abnormal findings should prompt referral in line with NICE guideline NG12 (Suspected cancer: recognition and referral). A full blood count and assessment of cardiovascular risk factors are also recommended.
Regular follow-up is essential. Monitoring schedules recommended by the Society for Endocrinology and BSSM typically include assessment of testosterone levels, haematocrit, PSA, and clinical response at 3, 6, and 12 months initially, then annually thereafter. If haematocrit rises above 0.54, dose reduction or temporary cessation should be considered. Elderly patients require particularly careful monitoring due to increased risk of prostate pathology and cardiovascular events.
How to Apply Testogel Safely and Effectively
Proper application technique is essential to ensure optimal absorption and minimise the risk of transfer to others, which is a significant safety concern with transdermal testosterone preparations. Testogel should be applied once daily, preferably at the same time each morning, to clean, dry, intact skin on the shoulders and/or upper arms (for the UK-marketed Testogel 16.2 mg/g formulation). The application site should be rotated to reduce the risk of skin irritation. Do not apply to broken or irritated skin, and avoid occlusive dressings.
Step-by-step application guidance:
- Wash and dry your hands thoroughly before opening the sachet or pump
- Apply the gel to the designated area (shoulders and/or upper arms), spreading it thinly and evenly
- Allow the gel to dry completely (approximately 3–5 minutes) before dressing
- Wash your hands thoroughly with soap and water immediately after application
- Cover the application site with clothing once the gel has dried
Critical safety measures to prevent testosterone transfer include:
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Avoiding skin-to-skin contact with others, particularly women (especially pregnant women) and children, until the application site has been washed
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Washing the application site with soap and water before any situation involving close physical contact
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Ensuring the treated area is covered with clothing
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Washing clothes that have been in contact with the application site before they are worn by others
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If contact with another person occurs, the contacted area should be washed immediately with soap and water
Patients should avoid swimming, showering, or vigorous exercise for at least 2 hours after application (for Testogel 16.2 mg/g) to allow adequate absorption. If a dose is missed, it should be applied as soon as remembered, unless it is nearly time for the next dose—in which case, the missed dose should be skipped.
Do not apply Testogel to the genital area, as this may cause local irritation. If skin irritation develops at the application site, consult your GP or specialist, as an alternative formulation or delivery method may be more appropriate.
Potential Side Effects and Safety Considerations
Like all medicines, Testogel can cause side effects, though not everyone experiences them. Understanding potential adverse effects enables patients to recognise concerning symptoms and seek timely medical advice when necessary.
Common side effects may include:
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Skin reactions at the application site (redness, itching, dry skin)
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Acne or oily skin
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Mood changes, including increased aggression or irritability
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Headache
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Changes in libido
Other side effects that may occur include:
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Increased blood pressure
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Prostate enlargement (benign prostatic hyperplasia)
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Polycythaemia (excessive red blood cell production)
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Fluid retention
Serious adverse effects requiring immediate medical attention include:
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Signs of polycythaemia: persistent headaches, dizziness, visual disturbances, or flushing
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Cardiovascular events: chest pain, shortness of breath, or leg swelling
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Allergic reactions: rash, swelling of the face or throat, difficulty breathing
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Prolonged or painful erections (priapism) lasting more than 4 hours
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Symptoms suggesting liver dysfunction (uncommon with transdermal testosterone): yellowing of skin or eyes, dark urine, persistent nausea
The MHRA and European Medicines Agency (EMA) have reviewed the cardiovascular safety of testosterone-containing medicines. Whilst the evidence is inconclusive and a causal link has not been established, cardiovascular risk cannot be excluded. Testosterone therapy should be used with caution in men with severe cardiovascular disease, and regular monitoring of cardiovascular risk factors is advised.
Regular monitoring of haematocrit is essential, as testosterone can stimulate red blood cell production. If haematocrit rises above 0.54 (54%), dose reduction or temporary cessation of treatment should be considered to reduce the risk of thrombotic events.
Important interactions:
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Coumarin anticoagulants (e.g., warfarin): Testosterone may enhance anticoagulant effects; monitor INR closely and adjust anticoagulant dose as needed
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ACTH or corticosteroids: Increased risk of fluid retention and oedema; monitor carefully
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Insulin or oral hypoglycaemic agents: Testosterone may reduce blood glucose; dose adjustments of antidiabetic therapy may be required
Fertility warning:
Exogenous testosterone can suppress spermatogenesis and reduce fertility. Men wishing to father children should discuss alternative treatments or strategies with their specialist before starting Testogel.
When to contact your GP or specialist:
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Development of new or worsening symptoms
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Concerns about side effects affecting quality of life
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Signs of testosterone transfer to family members (particularly virilisation in female partners or children)
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Any symptoms suggesting serious adverse effects
Patients should attend all scheduled monitoring appointments to ensure treatment remains safe and effective. If you experience side effects, you can report them via the MHRA Yellow Card scheme at www.mhra.gov.uk/yellowcard or search for 'Yellow Card' in the Google Play or Apple App Store. If you have concerns about Testogel or experience unexpected symptoms, contact your prescribing specialist or GP promptly rather than discontinuing treatment abruptly without medical guidance.
Frequently Asked Questions
Can Testogel be used for age-related low testosterone?
No, Testogel is not recommended for age-related testosterone decline in the absence of pathological hypogonadism. Treatment requires biochemical confirmation of consistently low testosterone levels alongside clinical symptoms, with reversible causes excluded.
How long does it take for Testogel to work?
Testosterone levels typically begin to rise within hours of application, with steady-state concentrations achieved after several days of consistent daily use. Clinical symptom improvement may take several weeks to become apparent.
What should I do if someone accidentally touches my Testogel application site?
If skin-to-skin contact occurs, the contacted area should be washed immediately with soap and water. To prevent transfer, always cover the application site with clothing once the gel has dried and wash the area before close physical contact.
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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