5 surprising things you may not realize affect your patients’ testosterone levels—and how to talk about them in the clinic

Testosterone has become one of the internet’s favorite biomarkers. Social media influencers promise to “boost T” with supplements, cold plunges, and elaborate workout routines, while direct-to-consumer clinics market testosterone testing to men who simply feel tired or stressed.

The reality is far less straightforward. Testosterone is released in pulses throughout the day, naturally fluctuates over time, and is influenced by everything from sleep and stress to medications.^[][]

That means a single lab value rarely tells the whole story. The bigger challenge for physicians is helping patients understand why their levels may have changed and when those changes are actually clinically meaningful.

Here are five surprising factors that can influence testosterone—and practical ways to discuss each one in the exam room.

1. Becoming a new father

Many new fathers are surprised to learn that parenthood itself can influence hormone levels. 

Research has found that men often experience significant reductions in testosterone after the birth of a child.^[]Other studies suggest levels begin returning toward baseline at 3 months postnatal to 9–10 months postnatal.^[]

This may be due to an evolutionary adaptation that promotes caregiving behavior.^[] Or, new fathers are simultaneously dealing with sleep deprivation, increased stress, changes in routine, and often less exercise—all of which independently affect testosterone.^[]

Many patients are reassured simply knowing that becoming a parent can temporarily affect hormone levels.

2. Their medication list

Patients often focus on supplements while overlooking medications that have much stronger evidence for suppressing testosterone. Several commonly prescribed drug classes can contribute.

Medications associated with lower testosterone include:

• Chronic opioids: Long-term opioid therapy suppresses the hypothalamic-pituitary-gonadal axis and can lead to clinically significant testosterone deficiency.^[]

• Glucocorticoids: Prolonged corticosteroid use may suppress testosterone production through effects on the hypothalamic-pituitary-gonadal axis.^[]

• Anabolic steroids: Patients using anabolic steroids to build muscle frequently suppress their own endogenous testosterone production.^[]

• Androgen-deprivation therapy and other prostate cancer treatments: These intentionally lower testosterone as part of cancer treatment.^[]

Patients are frequently surprised to learn their prescriptions, rather than aging alone, may be contributing to symptoms.

3. Training too hard

Exercise generally supports healthy testosterone production.^[] The problem comes when recovery never catches up with training. Indeed, excessive overtraining without adequate rest can actually suppress testosterone.^[]Rather than adapting positively, the body shifts into an energy-conserving state marked by elevated physiologic stress.

“Overtraining, characterized by excessive exercise without adequate rest, can actually have the opposite effect and lead to a decrease in your testosterone levels. Your body needs time to recover and rebuild,” said urologist Nelson E. Bennett, MD.^[]

The phenomenon has attracted attention recently thanks to viral discussions of “gym penis”—the temporary reduction in penile size some men notice immediately after intense workouts.^[]

While this is primarily related to blood flow redistribution and sympathetic activation rather than testosterone itself, it has prompted more patients to ask whether extreme training affects male hormones.^[]

4. Being a sports fan

Here’s one your patients may bring up after seeing headlines online. Some research has found that testosterone levels can temporarily rise when someone’s favorite sports team wins and fall after a loss.^[]

Researchers describe this as “basking in reflected glory”—the idea that emotionally identifying with a winning group produces measurable physiologic responses.^[]

The evidence is intriguing but limited. Studies have been small, testosterone changes are transient, and there is no evidence that being a devoted fan meaningfully alters long-term testosterone status.^[]

5. Chronic stress

Patients often assume stress affects mood—but not hormones. In reality, persistent psychological stress appears to have meaningful effects on testosterone regulation through sustained activation of the hypothalamic-pituitary-adrenal axis.^[]

Research has linked chronic stress with lower testosterone, erectile dysfunction, diminished sperm quality, and reduced libido.^[] Elevated cortisol and ongoing endocrine dysregulation likely play important roles.^[]

Stress can also indirectly lower testosterone by disrupting sleep, increasing alcohol use, reducing physical activity, and contributing to weight gain.^[]

Treat the patient, not the testosterone

Low testosterone is real, and appropriately selected patients can benefit substantially from treatment. But it’s equally important to remind patients that testosterone isn’t a scorecard for masculinity, athletic performance, or overall health.

Levels naturally fluctuate throughout the day, decline gradually with age, and respond to life circumstances ranging from new parenthood to medication use, stress, sleep, and training load.

When patients ask how to “optimize” testosterone, the conversation often shouldn’t begin with injections or supplements. It should begin with a review of medications, sleep habits, stress, exercise patterns, alcohol use, and other modifiable contributors. 

In many cases, improving those fundamentals will do more for a patient’s symptoms—and overall health—than chasing a single laboratory value ever could.