040 - Low T + Low D = No Gains: Testosterone’s Cardiometabolic Benefits Depend on Vitamin D
Men dealing with low testosterone (also known as late-onset hypogonadism, or LOH) often turn to Testosterone Replacement Therapy (TRT) to reclaim vitality, strength, and overall health. What if your Vitamin D levels determined how effectively TRT actually works?
New research says that's exactly what's happening.
A recent 2025 study in Nutrients explored whether Vitamin D status impacts the cardiometabolic benefits of testosterone therapy in men with LOH. Researchers split subjects into three groups based on their Vitamin D levels, then tracked how each responded to testosterone injections over six months.
WHAT THEY FOUND:
Men with normal Vitamin D levels saw impressive improvements:
Better insulin sensitivity
Reduced LDL ("bad") cholesterol
Lower inflammation markers (hsCRP)
Reduced homocysteine and uric acid (both linked to cardiovascular issues)
Improved overall cardiometabolic risk scores
Men with low Vitamin D, on the other hand, barely benefited:
Minimal improvements in inflammation
Decreased HDL ("good") cholesterol, actually worsening their lipid profile
Limited or no improvement in insulin sensitivity or cardiometabolic markers
Simply put, adequate Vitamin D unlocked TRT’s full potential, whereas deficiency significantly blunted the therapy’s effectiveness.
WHAT THIS MEANS:
Vitamin D isn't just a supplement; it's a critical co-factor that could make or break the effectiveness of testosterone treatment. If Vitamin D levels aren’t optimized, TRT might not just fall short; it might actively fail your health goals.
TACTICAL IMPLICATIONS
1. Test Before You Treat:
Ensure Vitamin D levels are checked and normalized before starting testosterone therapy.
2. Precision Matters:
TRT isn't plug-and-play. It's a precision medicine that needs supporting nutrients like Vitamin D to perform optimally.
3. Preventive Protocols:
Incorporate Vitamin D assessments into routine health checks for all tactical athletes or patients considering TRT.
4. Supplement Strategically:
Use evidence-based supplementation or sunlight exposure plans to maintain ideal Vitamin D status, enhancing TRT outcomes.
5. Monitor & Adapt:
Regularly track Vitamin D alongside testosterone levels to proactively adjust treatments, ensuring both remain in optimal ranges.
QUESTIONS TO CONSIDER
Have you ever checked your Vitamin D status alongside testosterone levels?
Are your protocols built around holistic health, or just isolated hormones?
What other key nutrients could you be overlooking that might impact hormonal therapies?
Krysiak R, Kowalcze K, Szkróbka W, Okopień B. Vitamin D Status Determines Cardiometabolic Effects of Testosterone Replacement Therapy in Men with Late-Onset Hypogonadism. Nutrients. 2025;17(6):1013. Published 2025 Mar 13. doi:10.3390/nu17061013