TRT and Kidney Function: What You Need to Know About Renal Health

Written by Adam Maggio | Medically reviewed by Dr. Sarah Chen, PharmD, BCPS

Low testosterone is common in men with chronic kidney disease (CKD), and while testosterone replacement therapy (TRT) can offer benefits for overall health, its impact on kidney function is complex. Emerging evidence suggests TRT may improve some renal parameters and reduce the risk of acute kidney injury, but careful monitoring of kidney function and potential side effects like fluid retention and polycythemia is essential, especially in men with pre-existing kidney conditions.

TRT and Kidney Function: A Critical Look at Renal Health

For men living with chronic kidney disease (CKD), low testosterone levels are a frequent comorbidity, affecting quality of life, muscle mass, and overall health. The decision to initiate testosterone replacement therapy (TRT) in this population requires a thorough understanding of its potential effects on renal function. While concerns about TRT exacerbating kidney issues have existed, a growing body of evidence suggests a more nuanced, and often beneficial, relationship.

The Interplay Between Low Testosterone and CKD

There's a bidirectional relationship between low testosterone and CKD. Men with CKD often experience hypogonadism due to various factors, including inflammation, nutritional deficiencies, and altered hormone metabolism. Conversely, low testosterone itself can contribute to muscle wasting, fatigue, and reduced quality of life, which are common in CKD patients (Zitzmann et al., 2024). Normalizing testosterone levels in these men can potentially alleviate some of these debilitating symptoms.

TRT's Potential Benefits for Kidney Function

Contrary to earlier apprehensions, recent research indicates that TRT may not only be safe but could also offer protective effects for kidney function:

• Reduced Risk of Acute Kidney Injury (AKI): A large real-world cohort study found that testosterone therapy was associated with a reduced risk of acute kidney injury (AKI) and kidney failure requiring renal replacement therapy in men with hypogonadism (Bonnet et al., 2025). This is a significant finding, as AKI can worsen CKD progression.
• Improved Glomerular Filtration Rate (GFR): Some studies suggest that long-term testosterone treatment can lead to an increase in GFR, a key measure of kidney function. For example, Alwani et al. (2021) observed improved kidney function, indicated by increased GFR, in hypogonadal men on long-term testosterone therapy.
• Indirect Benefits: Testosterone's positive effects on metabolic health, such as improved insulin sensitivity, reduced visceral adiposity, and increased muscle mass, can indirectly benefit kidney function. These systemic improvements can alleviate some of the metabolic burdens on the kidneys.
• Direct Renal Effects: Testosterone has been shown to exert direct effects on renal function, including modulation of renal blood flow and filtration (Zitzmann et al., 2024).

These findings challenge the notion that TRT is inherently detrimental to the kidneys and suggest that, for many hypogonadal men with CKD, the benefits may outweigh the risks when managed appropriately.

Potential Risks and Considerations

While the overall picture is encouraging, certain aspects of TRT still require careful consideration in men with kidney issues:

• Fluid Retention: Testosterone can cause fluid retention, which might be a concern for patients with advanced CKD or those on dialysis, where fluid balance is critical. This typically manifests as mild edema, but in severe cases, it could exacerbate hypertension or heart failure.
• Polycythemia: As discussed previously, TRT can increase hematocrit. While manageable, severe polycythemia leads to increased blood viscosity, which could theoretically strain kidney microcirculation, though direct evidence of kidney damage from TRT-induced polycythemia is rare.
• Pre-existing Conditions: Men with pre-existing severe kidney disease, especially those with rapidly declining function, require more cautious management and closer monitoring.

Unlike the clear hepatotoxicity of oral 17-alpha alkylated androgens, modern TRT formulations do not directly damage the kidneys. Any concerns typically revolve around exacerbating existing conditions rather than inducing new renal pathology.

Monitoring and Clinical Recommendations

For men with CKD on TRT, rigorous monitoring is essential:

• Baseline and Regular Kidney Function Tests: Your doctor will assess your baseline kidney function (e.g., creatinine, eGFR, BUN) before starting TRT and monitor these parameters regularly (e.g., every 3-6 months initially, then annually).
• Fluid Balance and Blood Pressure: Monitor for signs of fluid retention and ensure blood pressure remains well-controlled.
• Hematocrit Monitoring: Regular checks for polycythemia are crucial, with appropriate management strategies implemented if levels become elevated.
• Individualized Approach: The decision to initiate TRT in men with CKD should always be individualized, weighing the potential benefits against the risks, and involving a nephrologist if the CKD is advanced.

The goal is to optimize testosterone levels to improve symptoms of hypogonadism while safeguarding renal health. It's not a one-size-fits-all approach; close collaboration between your endocrinologist or urologist and your nephrologist is often beneficial.

Practical Takeaway

If you have low testosterone and kidney disease, don't assume TRT is off-limits. You'll need a thorough evaluation of your kidney function before starting therapy, and your doctor will monitor your blood tests, fluid balance, and blood pressure closely. While TRT can potentially improve some aspects of kidney health, it's not without considerations, especially regarding fluid retention and polycythemia. Always discuss any changes in your symptoms or lab results with your healthcare provider; they'll help you navigate TRT safely and effectively to improve your overall well-being.