Testogel is a prescription testosterone replacement therapy licensed in the UK for treating male hypogonadism. Many patients wonder: is Testogel a steroid? Yes, Testogel is classified as an anabolic-androgenic steroid because its active ingredient, testosterone, promotes both male characteristics and tissue growth. However, when prescribed for confirmed low testosterone and used under medical supervision, it is a safe, regulated treatment. This article explains what Testogel is, how it works, its medical uses, safety profile, and its legal classification under UK law.

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 body produces insufficient testosterone. It is available in two formulations: Testogel 50 mg (1%) gel in sachets and Testogel 16.2 mg/g gel in a metered-dose pump dispenser. Both contain testosterone as the active pharmaceutical ingredient.

The gel is applied once daily to clean, dry, intact skin. Application sites differ by formulation: the 1% sachet may be applied to the shoulders, upper arms, or abdomen, whereas the 16.2 mg/g pump is typically applied to the shoulders and upper arms only. Patients should never apply Testogel to the genitals or broken, irritated skin. Once applied, testosterone is absorbed through the skin into the bloodstream over several hours. This transdermal delivery system provides steadier serum testosterone concentrations than many intramuscular injection regimens, though it does not reproduce the body's normal circadian variation.

Mechanism of action: Testosterone is an endogenous androgen hormone responsible for the development and maintenance of male secondary sexual characteristics, muscle mass, bone density, libido, and overall wellbeing. In men with hypogonadism, exogenous testosterone supplementation via Testogel restores physiological testosterone levels. The hormone binds to androgen receptors in target tissues, influencing gene transcription and protein synthesis, thereby alleviating symptoms such as fatigue, reduced libido, erectile dysfunction, loss of muscle mass, and mood disturbances.

Testogel is absorbed systemically and metabolised primarily in the liver. Steady-state plasma concentrations are typically achieved within a few days of consistent application. Regular monitoring of serum testosterone levels is essential to ensure therapeutic efficacy and avoid supraphysiological levels, which may increase the risk of adverse effects.

Important application and safety advice:

• Allow the application site to dry completely before dressing (the gel contains alcohol and is flammable until dry).

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

• Cover the application site with clothing once dry to prevent unintended testosterone transfer to others—particularly women and children.

• Avoid washing the application site for at least 2 hours after applying the 16.2 mg/g pump formulation, or at least 6 hours for the 1% sachet. Showering or bathing before anticipated close skin-to-skin contact with others is advised.

• Report any signs of virilisation in household contacts (such as unexpected hair growth, voice deepening, or acne) to your GP immediately.

Further information is available in the patient information leaflet and Summary of Product Characteristics (SmPC) on the electronic Medicines Compendium (eMC) and in the British National Formulary (BNF).

Medical Uses of Testogel in the UK

In the UK, Testogel is licensed exclusively for testosterone replacement therapy in adult males with confirmed hypogonadism. Hypogonadism may be primary (testicular failure) or secondary (hypothalamic-pituitary dysfunction). Diagnosis requires both clinical symptoms and biochemical confirmation of low serum testosterone levels.

Diagnostic approach (per NICE Clinical Knowledge Summaries and UK endocrine guidance):

• Measure total testosterone on two separate occasions in the early morning (ideally between 7–11 am, when testosterone levels are naturally highest), using a reliable assay.

• If results are borderline (typically 8–12 nmol/L) or sex hormone-binding globulin (SHBG) is abnormal, measure SHBG and calculate free or bioavailable testosterone.

• Total testosterone <8 nmol/L is generally considered low; 8–12 nmol/L is borderline and should be interpreted alongside symptoms and free testosterone.

• Assess for reversible causes of low testosterone, including obesity, obstructive sleep apnoea (OSA), opioid use, systemic illness, and certain medications.

• Baseline investigations typically include luteinising hormone (LH), follicle-stimulating hormone (FSH), prolactin, and sometimes additional tests to exclude secondary causes. Consider specialist endocrinology referral if the diagnosis is uncertain or secondary hypogonadism is suspected.

Common indications include:

• Primary hypogonadism: Conditions such as Klinefelter syndrome, testicular trauma, chemotherapy, or radiotherapy-induced testicular damage.

• Secondary hypogonadism: Pituitary tumours, hyperprolactinaemia, or idiopathic hypogonadotropic hypogonadism.

• Age-related (late-onset) hypogonadism: Some older men experience a gradual decline in testosterone. TRT is only recommended when symptoms are present alongside confirmed low testosterone levels on repeat testing.

Testogel is not licensed for:

• Performance enhancement or bodybuilding.

• Treatment of age-related decline in testosterone in asymptomatic men.

• Use in women or children (except in rare, specialist-supervised cases).

Fertility counselling: Exogenous testosterone suppresses spermatogenesis and can markedly reduce sperm counts. TRT is not a treatment for infertility. Men actively seeking to father children should discuss alternative management or specialist referral before starting testosterone therapy.

Monitoring and follow-up:

Once initiated, patients require regular follow-up to assess clinical response, tolerability, and safety. Typical monitoring includes:

• Testosterone levels: Check at 3–6 months, then annually. Adjust dose if levels are suboptimal or supraphysiological.

• Full blood count (FBC) and haematocrit: Check at baseline, 3–6 months, then annually. If haematocrit rises >0.54, consider dose reduction or temporary cessation and investigate for other causes of polycythaemia.

• Prostate-specific antigen (PSA) and digital rectal examination (DRE): Baseline and periodic monitoring as per individual risk. Refer to urology if PSA rises >1.4 ng/mL within 12 months, or if DRE is abnormal or lower urinary tract symptoms (LUTS) develop.

• Liver function tests (LFTs): As per local policy or if clinically indicated.

• Clinical review: Assess symptom improvement, mood, libido, energy, and any adverse effects.

Do not initiate TRT in men with known or suspected prostate or male breast cancer. Further guidance is available in NICE Clinical Knowledge Summaries (CKS) on hypogonadism, the BNF, and specialist society guidance (e.g., Society for Endocrinology UK, British Society for Sexual Medicine).

Safety and Regulation of Testogel Under UK Law

Testogel is a prescription-only medicine (POM) in the UK, regulated by the Medicines and Healthcare products Regulatory Agency (MHRA). It cannot be legally obtained without a valid prescription from a registered medical practitioner. This regulatory status reflects the need for medical supervision due to potential adverse effects and the risk of misuse.

Testosterone is also a Class C controlled drug under the Misuse of Drugs Act 1971 and is listed in Schedule 4 Part II of the Misuse of Drugs Regulations 2001. Simple possession for personal use is not a criminal offence (except in prisons). However, supply or intent to supply is illegal, as is import or export by post or courier services. Personal carriage of prescribed testosterone when travelling may be permitted for personal use, but patients should carry a copy of their prescription and check destination country regulations.

Adverse effects may include:

• Skin reactions at the application site (erythema, irritation, dryness, pruritus).

• Acne and oily skin.

• Mood changes, including irritability, aggression, or low mood.

• Polycythaemia (increased red blood cell count), which may increase cardiovascular risk.

• Prostate enlargement or worsening of benign prostatic hyperplasia (BPH) and lower urinary tract symptoms.

• Gynaecomastia (breast tissue enlargement).

• Fluid retention and oedema.

• Headache.

Frequencies of these effects vary; consult the patient information leaflet or SmPC for detailed information.

Contraindications include:

• Known or suspected prostate cancer or male breast cancer.

• Hypersensitivity to testosterone or any excipients.

Cautions and warnings (requiring careful monitoring and clinical judgement):

• Cardiovascular disease: Some studies suggest a potential association between TRT and increased cardiovascular events, though evidence remains inconclusive. Use with caution in men with ischaemic heart disease, heart failure, or stroke.

• Obstructive sleep apnoea: TRT may exacerbate OSA; monitor and manage appropriately.

• Severe cardiac, renal, or hepatic insufficiency: Use with caution and monitor closely.

• Epilepsy or migraine: May be exacerbated by fluid retention.

• Polycythaemia or risk factors for thromboembolism.

Patient safety advice:

• Apply Testogel to clean, dry, intact skin (not to genitals or broken/irritated skin) and allow it to dry fully before dressing.

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

• Cover the application site with clothing once dry to prevent skin-to-skin transfer to others.

• Avoid washing the application site for at least 2 hours (16.2 mg/g pump) or 6 hours (1% sachet) after application. Shower or bathe before anticipated close contact with others, especially women and children.

• The gel contains alcohol and is flammable until dry; avoid fire, flames, and smoking until the application site is completely dry.

When to contact your GP:

• Persistent skin irritation or allergic reactions.

• Mood changes, aggression, anxiety, or depression.

• Difficulty urinating, increased frequency, or other urinary symptoms.

• Chest pain, shortness of breath, or leg swelling.

• Unexplained weight gain or swelling.

• Signs of virilisation in household contacts (women or children).

Reporting suspected 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 search for MHRA Yellow Card in the Google Play or Apple App Store. Reporting helps provide more information on the safety of medicines.

Further safety information is available in the MHRA Drug Safety Update on transdermal testosterone transfer, the BNF, and the eMC SmPCs for Testogel formulations.

Is Testogel Classified as a Steroid?

Yes, Testogel is classified as an anabolic-androgenic steroid (AAS). Testosterone, the active ingredient in Testogel, is both an androgen (promoting male characteristics) and an anabolic agent (promoting tissue growth, particularly muscle and bone). All testosterone preparations, including Testogel, fall under the broader category of anabolic steroids.

In the UK, testosterone is a Class C controlled drug under the Misuse of Drugs Act 1971 and is listed in Schedule 4 Part II of the Misuse of Drugs Regulations 2001. Simple possession of testosterone for personal use is not a criminal offence (except in prisons). However, supply or intent to supply is illegal and punishable by law. Import or export by post or courier services is also illegal. Personal carriage of prescribed testosterone when travelling for personal use may be permitted, but patients should carry evidence of their prescription and check the regulations of their destination country.

It is important to distinguish between therapeutic use and misuse. When prescribed for legitimate medical reasons—specifically, confirmed hypogonadism—Testogel is a safe and effective treatment under medical supervision. The European Medicines Agency (EMA) and MHRA emphasise that testosterone replacement therapy should only be used for confirmed hypogonadism and under ongoing medical supervision.

However, misuse of anabolic steroids for performance enhancement or bodybuilding carries significant health risks, including:

• Cardiovascular complications: Hypertension, myocardial infarction, stroke, and adverse lipid profiles.

• Hepatic effects: Hepatotoxicity is primarily associated with 17-alpha-alkylated oral anabolic steroids. Transdermal testosterone has a different hepatic risk profile, though liver function should still be monitored as clinically indicated.

• Psychiatric effects: Aggression, mood swings, anxiety, depression, and, in some cases, dependency.

• Reproductive dysfunction: Testicular atrophy, reduced sperm production, and infertility.

• Endocrine effects: Suppression of natural testosterone production, gynaecomastia.

• Polycythaemia and thromboembolism risk.

• Dependency and withdrawal symptoms upon cessation.

Patients prescribed Testogel should never share their medication with others, even if they appear to have similar symptoms. Any concerns about testosterone therapy, its effects, or its legal status should be discussed with a healthcare professional.

In summary, while Testogel is indeed a steroid, its classification reflects its pharmacological properties rather than implying it is unsafe. When used appropriately for licensed indications—confirmed male hypogonadism—and under proper medical supervision, it is a valuable and well-regulated therapeutic option. Misuse outside of medical supervision is both illegal and dangerous.

Further information is available from the MHRA, the BNF, NICE Clinical Knowledge Summaries, and the eMC SmPCs for Testogel formulations.

Frequently Asked Questions