Can testosterone treatment hurt your kidneys? Testosterone replacement therapy (TRT) is prescribed to men with clinically confirmed hypogonadism to address symptoms such as fatigue, reduced libido, and loss of muscle mass. Whilst current evidence suggests testosterone does not directly damage healthy kidneys in most patients, concerns arise regarding its effects on fluid balance, blood pressure, and haematocrit—factors that may indirectly affect renal health. Men with pre-existing chronic kidney disease, uncontrolled hypertension, or cardiovascular conditions require careful assessment and monitoring. This article examines the relationship between testosterone therapy and kidney function, identifies risk factors, and outlines essential monitoring strategies to ensure safe treatment.

Can Testosterone Treatment Hurt Your Kidneys?

Testosterone replacement therapy (TRT) is prescribed to men with clinically confirmed hypogonadism—a condition where the body produces insufficient testosterone. Whilst testosterone therapy can effectively address symptoms such as fatigue, reduced libido, and loss of muscle mass, patients and clinicians alike often question whether this treatment poses risks to kidney function.

Current evidence suggests that testosterone therapy does not directly damage healthy kidneys in most patients. Testosterone is primarily metabolised in the liver, with its metabolites being excreted by the kidneys. Therapeutic doses prescribed according to clinical recommendations are generally well-tolerated by individuals with normal renal function. However, testosterone can influence fluid balance and electrolyte regulation, which may indirectly affect kidney health in certain circumstances.

Testosterone therapy may cause fluid retention and increased haematocrit (red blood cell concentration), both of which can place additional strain on the cardiovascular system. In patients with pre-existing kidney disease, these effects may exacerbate underlying renal impairment or contribute to hypertension, which itself is a major risk factor for progressive kidney damage. Additionally, some formulations of testosterone may affect lipid profiles and blood pressure, further complicating the clinical picture in vulnerable individuals.

It is important to emphasise that there is limited evidence suggesting testosterone is directly nephrotoxic when used appropriately. The key consideration is patient selection and ongoing monitoring. Men with established chronic kidney disease (CKD), uncontrolled hypertension, heart failure, or prostate cancer require careful assessment before initiating testosterone therapy, and regular monitoring throughout treatment is essential to ensure safety and efficacy.

Risk Factors for Kidney Problems During Testosterone Treatment

Certain patient characteristics and comorbidities increase the likelihood of kidney-related complications during testosterone therapy. Understanding these risk factors enables clinicians to identify individuals who require enhanced surveillance or alternative management strategies.

Pre-existing chronic kidney disease is the most significant risk factor. Patients with CKD stages 3–5 have reduced renal reserve and impaired ability to regulate fluid and electrolyte balance. Testosterone-induced fluid retention may worsen oedema, hypertension, and cardiac strain in this population. UK product information advises caution when prescribing testosterone to men with severe renal insufficiency, and dose adjustments or alternative treatments may be necessary.

Cardiovascular disease and uncontrolled hypertension represent additional risk factors. Testosterone can potentially increase blood pressure through fluid retention. Elevated blood pressure is a leading cause of kidney damage, and poorly controlled hypertension during TRT may accelerate the progression of renal disease. Patients with heart failure are particularly vulnerable, as fluid retention can precipitate acute decompensation.

Other important risk factors include:

• Diabetes mellitus – diabetic nephropathy is a common cause of CKD, and testosterone's effects on insulin sensitivity and metabolic parameters require careful monitoring

• Polycythaemia – testosterone stimulates erythropoiesis, and excessive haematocrit elevation (≥54%) increases blood viscosity, potentially increasing thrombosis risk

• Concurrent nephrotoxic medications – non-steroidal anti-inflammatory drugs (NSAIDs), certain antibiotics, and other agents may compound renal risk

• Advanced age – older men often have reduced baseline renal function and multiple comorbidities

Patients with multiple risk factors require individualised assessment, and shared decision-making should weigh the potential benefits of testosterone therapy against kidney-related risks.

Monitoring Kidney Health While on Testosterone Therapy

Monitoring is essential for all patients receiving testosterone therapy, with kidney function tests particularly important for those with identified risk factors. UK clinical practice emphasises the importance of baseline assessment and ongoing surveillance to detect adverse effects early and enable timely intervention.

Before initiating testosterone therapy, clinicians should obtain baseline investigations including haematocrit, haemoglobin, PSA (prostate-specific antigen), testosterone levels, and blood pressure. For men with risk factors for kidney disease, baseline serum creatinine, estimated glomerular filtration rate (eGFR), and urinalysis are also important. These tests establish the patient's status and provide reference points for future comparisons.

During treatment, standard monitoring includes:

• Haematocrit and haemoglobin – checked at 3–6 months, 12 months, then annually; if haematocrit reaches ≥54%, treatment should be adjusted, temporarily stopped, or venesection considered

• Blood pressure – measured at each clinical encounter, with home monitoring encouraged for at-risk patients

• Serum testosterone – to ensure levels are maintained within the therapeutic range

• PSA and prostate assessment – according to age and risk factors

For patients with CKD or kidney risk factors, additional monitoring includes:

• Serum creatinine and eGFR – frequency determined by CKD stage as per NICE guidance

• Urinalysis – to detect proteinuria, which may indicate kidney damage

• Signs of fluid retention – if oedema or heart failure develops, testosterone therapy should be stopped and reviewed

Patients should be educated about the importance of attending monitoring appointments and reporting new symptoms promptly. Dose adjustments or treatment discontinuation may be necessary if kidney function deteriorates or other safety concerns arise.

When to Seek Medical Advice About Testosterone and Kidney Health

Patients receiving testosterone therapy should be aware of warning signs that may indicate kidney problems or other complications requiring urgent medical attention. Early recognition and prompt intervention can prevent serious adverse outcomes and preserve renal function.

Contact your GP or healthcare provider if you experience:

• Significant swelling of the ankles, legs, or face—this may indicate fluid retention and impaired kidney function

• Unexplained weight gain of more than 2–3 kg over a few days, suggesting fluid accumulation

• Reduced urine output or noticeable changes in urine colour (particularly dark or bloody urine)

• Persistent fatigue or weakness that differs from your baseline symptoms

• Shortness of breath or difficulty breathing, especially when lying flat

• Severe or persistent headaches, which may indicate elevated blood pressure

• Chest pain or palpitations—cardiovascular complications can affect kidney perfusion

Seek immediate medical attention (call 999 or attend A&E) if you develop:

• Severe chest pain or pressure

• Sudden severe shortness of breath

• Confusion or altered consciousness

• Seizures or loss of consciousness

Patients with known kidney disease should maintain regular contact with their nephrology team and inform them about testosterone therapy. Any deterioration in kidney function detected through monitoring should prompt discussion with your prescribing clinician about whether treatment modification is necessary.

Do not change or stop testosterone therapy without medical advice, as symptoms may return if stopped. If you have concerns about kidney health or other side effects, schedule an appointment with your GP or endocrinologist to discuss your symptoms and review your treatment plan. You can also report suspected side effects to the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk). Your healthcare team can assess whether investigations are needed and determine the most appropriate course of action to protect both your hormonal health and kidney function.

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