Testosterone is far more than a marker of sexual health; it's one of the single best indicators of a man's overall health and future disease risk. Men with low testosterone face significantly higher odds of cardiovascular events, bone fractures, diabetes, obesity, depression, and anemia. A leading urology expert now argues that every man over 40 should have his testosterone checked annually, a recommendation that could reshape how men approach preventive health.

What Does Low Testosterone Really Signal About Your Health?

When testosterone levels drop, it's not just about energy or libido. According to Dr. Mohit Khera, a professor of urology at Baylor College of Medicine who recently led a U.S. Food and Drug Administration (FDA) expert panel on testosterone therapy, low testosterone functions as a warning system for broader health problems.

Dr. Mohit Khera, a professor of urology at Baylor College of Medicine who recently led a U

"Testosterone is one of the best markers of a man's current and future health, not just erections and libido. A man who has low testosterone is much more likely to have a cardiovascular event, heart attack. A man with low testosterone levels is much more likely to have a bone fracture, osteopenia, osteoporosis. More likely to have diabetes, obesity, metabolic syndrome. More likely to suffer from depression. More likely to have anemia," said Dr. Khera.

Dr. Mohit Khera, Professor of Urology at Baylor College of Medicine

Dr. Khera emphasizes that testosterone outperforms other common health markers in predicting overall wellness. "Show me another blood test that's a better marker of a man's overall health," he noted. "It's not his hemoglobin A1C. It's not his TSH (thyroid stimulating hormone). Serum testosterone is the single best marker of a man's overall health. When a man's testosterone is low, I call it the check engine light. That means something is going on. Something wrong is happening. And basically, we need to investigate and see what's happening".

Dr. Khera

Why Is the FDA Reconsidering Testosterone Therapy Guidelines?

Currently, the FDA approves testosterone therapy only for men with specific medical conditions, such as pituitary tumors or testicular injury. However, this approach leaves a significant gap: approximately 85% of men with low testosterone and symptoms don't have these specific conditions and are therefore considered off-label candidates for treatment.

In December 2025, Dr. Khera moderated an FDA expert panel to discuss expanding the label for testosterone therapy products. The key argument centers on symptom-based rather than condition-based approval. A man with low testosterone due to an unknown cause (idiopathic hypogonadism) experiences the same health risks and symptoms as a man whose low testosterone stems from a pituitary tumor. Both would benefit equally from treatment, yet current FDA guidelines only approve therapy for the latter.

The FDA is now considering adding low libido as a qualifying symptom for testosterone therapy, a shift that aligns with how major medical guidelines already approach the condition. This change could make treatment more accessible to symptomatic men who currently fall outside FDA approval.

Is Age-Related Testosterone Decline Inevitable?

Many men assume that testosterone naturally plummets with age, but this assumption is misleading. While testosterone does decline gradually over time, a healthy 80-year-old man should maintain levels above 300 nanograms per deciliter (ng/dL), the threshold used to define deficiency.

The real culprit behind significant testosterone drops in older men is not age itself, but the accumulation of chronic health conditions. Diabetes, obesity, metabolic syndrome, and sleep apnea all suppress testosterone production. As men age, they're more likely to develop these conditions, which then drive testosterone down. "Age-related testosterone deficiency is a misnomer," Dr. Khera explained. "It's not really true. For example, as a man gets older, yes, his testosterone levels decline, but they don't decline significantly to cause hypogonadism towards the end of his life".

Dr. Khera

How to Determine If You're a Candidate for Testosterone Therapy

• Testosterone Level: Two morning blood tests showing levels below 300 to 350 ng/dL, depending on the medical society's guidelines being followed.
• Symptoms Present: Low energy, reduced libido, erectile dysfunction, increased body fat, or decreased muscle mass that align with low testosterone.
• Not Trying to Conceive: Testosterone therapy significantly decreases sperm count and can cause infertility, making it inappropriate for men actively trying to father children.
• Not Seeking Supraphysiological Levels: Men with normal testosterone who want to reach unnaturally high levels (1,000 to 3,000 ng/dL) for performance enhancement are not appropriate candidates.
• Symptomatic Improvement Goal: The aim is to raise testosterone into the normal range and relieve symptoms, not simply to improve lab numbers.

What New Research Shows About Testosterone and Metabolic Disease

Recent evidence suggests testosterone therapy may help prevent and treat type 2 diabetes. The T4DM study, conducted in Australia with over 1,000 participants, found that men receiving testosterone injections showed significant reductions in developing diabetes or experienced regression of existing diabetes compared to those receiving placebo.

Similarly, men with low testosterone face higher obesity risk, and testosterone therapy may help address this metabolic problem. Dr. Khera noted that "we're in a new era where testosterone may be helping with metabolic disease." However, he cautioned that while the signals are promising, "we're not there yet. It's just a signal that it potentially may be used to treat these metabolic conditions".

Dr. Khera

Beyond metabolic benefits, testosterone therapy has shown promise for bone health, muscle mass preservation (particularly important for preventing sarcopenia, or age-related muscle loss), depression, libido, erectile function, and sleep quality in some patients.

What Should Happen After Starting Testosterone Therapy?

If a man and his doctor decide testosterone therapy is appropriate, patience is essential. The benefits don't appear overnight. Dr. Khera advises patients to try the medication for three months before reassessing. "The goal of this treatment is not to simply improve the numbers. The main goal is to improve the symptoms. So I tell patients it can take up to 3 months to see the benefit. Try the medication for 3 months, come back, and we'll re-evaluate," he explained.

If a patient experiences no symptom improvement after three months, it's reasonable to question whether continuing therapy makes sense. The focus remains on symptom relief and improved quality of life, not on achieving higher testosterone numbers for their own sake.

The shift toward annual testosterone screening for men over 40 and the FDA's reconsideration of therapy indications reflect a growing recognition that testosterone is a critical health marker deserving routine attention. As Dr. Khera emphasized, checking testosterone annually starting at age 40 could help identify health problems early, much like the warning light on a car's dashboard signals that something needs investigation.