Many men using testosterone replacement therapy wonder whether stopping treatment might affect their prostate cancer risk. Testogel is a widely prescribed transdermal testosterone gel used to treat confirmed hypogonadism in men with low testosterone levels. Whilst the relationship between testosterone and prostate health is complex, current medical evidence provides reassurance about treatment cessation. This article examines whether discontinuing Testogel increases prostate cancer risk, explores the science behind testosterone and prostate health, and outlines appropriate monitoring strategies for men using or stopping testosterone replacement therapy.

Understanding Testogel and Testosterone Replacement Therapy

Testogel is a transdermal testosterone gel licensed in the UK for testosterone replacement therapy (TRT) in men with confirmed hypogonadism—a condition characterised by abnormally low testosterone levels. The gel is applied daily to clean, dry skin, with application sites depending on the formulation (Testogel 16.2 mg/g pump is applied to upper arms/shoulders, while Testogel 1% sachets can be applied to the abdomen). Once applied, testosterone is absorbed through the skin into the bloodstream, helping to restore physiological testosterone concentrations.

Testosterone replacement therapy aims to alleviate symptoms associated with testosterone deficiency, which may include:

• Reduced libido and sexual dysfunction

• Fatigue and decreased energy levels

• Loss of muscle mass and strength

• Mood disturbances, including low mood or irritability

• Reduced bone density

Before initiating TRT, clinicians should confirm biochemical hypogonadism through at least two early-morning serum testosterone measurements, taken on separate occasions. Additional baseline assessments typically include LH/FSH, full blood count (to check haematocrit), and sometimes SHBG and prolactin if clinically indicated. According to guidance from the British Society for Sexual Medicine and the Society for Endocrinology, TRT should only be prescribed when there is clear clinical and biochemical evidence of testosterone deficiency.

The mechanism of action involves supplementing endogenous testosterone production, which naturally declines with age (approximately 1–2% per year after age 30). Testogel contains testosterone in a hydroalcoholic gel base that allows controlled absorption. Once absorbed, testosterone exerts its effects through androgen receptors in various tissues, influencing sexual function, muscle and bone metabolism, mood regulation, and other physiological processes.

Important safety considerations include preventing gel transfer to others (particularly women and children) by washing hands after application and covering the application site with clothing. Testogel is contraindicated in men with known or suspected prostate or breast cancer.

The Link Between Testosterone and Prostate Cancer Risk

The relationship between testosterone and prostate cancer has been extensively studied and remains an area of ongoing clinical research. Historically, there was concern that testosterone might stimulate prostate cancer growth, stemming from observations that androgen deprivation therapy (reducing testosterone) can slow advanced prostate cancer progression. However, current evidence does not support the notion that normal or elevated testosterone levels cause prostate cancer in men without pre-existing disease.

Large-scale studies and meta-analyses have found no convincing evidence that TRT increases the risk of developing prostate cancer in men with normal prostates. The European Association of Urology guidelines and systematic reviews indicate that there is insufficient evidence to conclude that testosterone therapy increases prostate cancer risk. Similarly, research published in reputable journals has shown that men on TRT do not demonstrate higher rates of prostate cancer compared to those not receiving treatment, when properly screened beforehand.

What is well-established is that testosterone can stimulate the growth of existing prostate cancer cells. This is why TRT is contraindicated in men with known prostate cancer or those with a palpable prostate nodule or induration on examination. Before starting TRT, clinicians should:

• Consider performing a digital rectal examination (DRE)

• Measure prostate-specific antigen (PSA) levels

• Assess lower urinary tract symptoms

• Consider individual risk factors including age and family history

Men with PSA above the age-specific reference range or abnormal DRE findings should be referred to urology for further assessment before TRT is considered, following the NICE NG12 suspected cancer referral pathway. The key principle is that testosterone does not appear to initiate prostate cancer but may accelerate pre-existing disease, making thorough assessment essential.

What Happens When You Stop Using Testogel

When a man discontinues Testogel, his exogenous testosterone supply ceases, and serum testosterone levels typically return to pre-treatment baseline within several days to weeks, depending on individual factors. According to the Testogel Summary of Product Characteristics (SmPC), testosterone levels begin to decline within 24-48 hours after the last application, though complete return to baseline may take longer.

Physiological changes upon cessation may include the return of hypogonadal symptoms if the underlying testosterone deficiency has not resolved. Men may experience:

• Recurrence of fatigue and reduced energy

• Decreased libido and sexual function

• Mood changes, including low mood or irritability

• Gradual loss of muscle mass and strength gains achieved during treatment

• Potential changes in body composition (increased fat mass)

The body's natural testosterone production may or may not recover, depending on the cause of the original hypogonadism. In cases of secondary hypogonadism (where the pituitary gland or hypothalamus is affected), the hypothalamic-pituitary-gonadal (HPG) axis may resume function after TRT cessation, though this can take several months. In primary hypogonadism (testicular failure), natural production is unlikely to improve significantly.

Some men may experience a temporary period of particularly low testosterone immediately after stopping, as the HPG axis takes time to reactivate. This can result in more pronounced symptoms during the transition period. There is no evidence that stopping TRT causes harm to the prostate or other organs, though the return of hypogonadal symptoms can significantly impact quality of life. Men considering discontinuation should discuss this decision with their prescribing clinician to ensure appropriate monitoring and management of any symptoms that return.

Does Stopping Testogel Increase Prostate Cancer Risk?

There is no scientific evidence suggesting that stopping Testogel increases the risk of developing prostate cancer. This concern, whilst understandable given the complex relationship between testosterone and prostate health, is not supported by current medical literature or clinical guidelines.

The cessation of testosterone therapy results in declining testosterone levels, which—if anything—would theoretically reduce any potential stimulatory effect on existing prostate tissue rather than increase cancer risk. Prostate cancer development is a multifactorial process influenced by:

• Genetic predisposition and family history

• Age (risk increases significantly after 50)

• Ethnicity (higher risk in men of African-Caribbean descent)

• Lifestyle factors including diet and obesity

• Possibly chronic inflammation

None of these risk factors are directly influenced by the act of stopping testosterone replacement therapy. What may occur, however, is that men who discontinue TRT might subsequently undergo prostate assessment or develop symptoms that lead to cancer detection—but this represents diagnosis of pre-existing disease rather than causation by treatment cessation.

It is worth noting that some studies have explored whether fluctuating testosterone levels (rather than consistently low or normal levels) might theoretically affect prostate tissue, but there is no robust evidence that the transition from supplemented to baseline testosterone increases malignancy risk. The prostate gland responds to androgens, but the withdrawal of exogenous testosterone does not trigger carcinogenic changes.

Men who stop Testogel should continue with age-appropriate PSA testing as recommended for all men in their age group. The NHS does not have a national prostate cancer screening programme, but men aged 50 and over (or 45 for those at higher risk) can request PSA testing after an informed discussion about the benefits and limitations. Any concerns about prostate health should be discussed with a GP, who can arrange appropriate investigations based on individual risk factors and clinical presentation.

Prostate Health Monitoring During and After TRT

Appropriate monitoring of prostate health is essential both during testosterone replacement therapy and following its discontinuation. Current UK guidance recommends a structured approach to surveillance that balances cancer detection with avoiding unnecessary investigations.

Before starting TRT, baseline assessments should include:

• Digital rectal examination (DRE) to assess prostate size, consistency, and detect any nodules

• Serum PSA measurement

• Assessment of lower urinary tract symptoms using validated questionnaires (e.g., International Prostate Symptom Score)

• Discussion of individual risk factors

During ongoing TRT, monitoring protocols typically involve:

• PSA measurement at 3 months, 12 months after initiation, then annually

• Consider DRE annually, particularly in men over 50 or those with risk factors

• Assessment of urinary symptoms at each review

• Evaluation of any new symptoms suggestive of prostate disease

Clinicians should be alert to PSA changes that warrant further investigation. According to NICE NG12 guidance, concerning patterns include:

• PSA above the age-specific reference range

• A PSA increase of 1.4 ng/mL or more within 12 months

• Any palpable abnormality on DRE

After stopping Testogel, men should continue age-appropriate PSA testing. The NHS does not have a national prostate cancer screening programme, but men can have an informed discussion about PSA testing with their GP. Men aged 50 and over (or 45 for those at higher risk) can request PSA testing after discussing the benefits, limitations and potential consequences of the test. Former TRT users should inform their GP of their treatment history, as this context may influence interpretation of results and clinical decision-making.

Men experiencing lower urinary tract symptoms (hesitancy, weak stream, nocturia, urgency) should seek medical assessment regardless of TRT status, as these may indicate benign prostatic hyperplasia, prostatitis, or occasionally malignancy.

When to Seek Medical Advice About Testogel and Prostate Concerns

Men using or discontinuing Testogel should be aware of specific symptoms and circumstances that warrant prompt medical attention. Speak to your GP if you experience:

• Urinary symptoms including inability to pass urine (urinary retention), visible blood in urine (haematuria), or persistent pain on urination

• New or worsening lower urinary tract symptoms such as significantly increased frequency, urgency, or nocturia that affects quality of life

• Pelvic or perineal pain that is persistent or unexplained

• Bone pain, particularly in the back, hips, or pelvis, which could indicate advanced disease (though this is rare)

Routine medical review is appropriate when:

• You are considering stopping Testogel and want to discuss the implications

• You have concerns about prostate cancer risk related to your TRT

• You are due for annual monitoring whilst on TRT

• You have a family history of prostate cancer (father or brother diagnosed, especially before age 60)

• You are of African-Caribbean ethnicity, which confers higher baseline risk

• You experience return of hypogonadal symptoms after stopping treatment

It is important to maintain open communication with your healthcare provider about any concerns regarding testosterone therapy and prostate health. Speak to your prescriber before stopping Testogel, as they can help plan the transition and monitor for any symptoms that may return.

If you have stopped Testogel and subsequently develop concerning symptoms, do not assume these are simply due to treatment cessation—seek medical assessment to exclude other causes. Remember that whilst the relationship between testosterone and prostate cancer is complex, appropriate monitoring and timely investigation of symptoms provide the best approach to maintaining prostate health. Your GP can arrange referral to urology services if investigations suggest possible prostate pathology requiring specialist assessment.

If you experience any side effects while using Testogel, report them to your doctor and consider reporting them through the MHRA Yellow Card scheme (yellowcard.mhra.gov.uk).

Frequently Asked Questions