If you’re a man in your 30s or 40s feeling persistently tired, mentally foggy, and less sharp — there’s a good chance your testosterone has something to do with it. Research shows average testosterone levels in men have been declining by roughly 1% per year, a trend that has accelerated over 40 years.
This article draws on clinical insights from Peter Attia, MD and Mark Hyman, MD. For educational purposes only — not medical advice.
What Testosterone Actually Does
Testosterone is not just about libido and muscle. It drives muscle protein synthesis, fat metabolism (particularly visceral fat reduction), bone density, red blood cell production, cognitive function, mood and motivation, cardiovascular health, insulin sensitivity, and sleep quality. Peter Attia describes it as one of the key “levers” in his longevity framework — when it’s optimized, everything else works better.
Six Drivers of Declining Testosterone
- Chronic sleep deprivation — just one week of sleeping 5 hours/night reduced testosterone by 10–15% in young men (University of Chicago, 2011)
- Chronic stress and elevated cortisol — cortisol and testosterone have an inverse relationship via the HPA axis
- Obesity and metabolic dysfunction — visceral fat contains aromatase, converting testosterone to estrogen; low testosterone promotes fat storage creating a self-perpetuating cycle
- Endocrine-disrupting chemicals — phthalates, BPA, PFAS, pesticides acting as xenoestrogens
- Poor diet and nutritional deficiencies — zinc and magnesium are essential cofactors for testosterone synthesis
- Physical inactivity — resistance training is one of the most reliable stimuli for testosterone production
The Problem With “Normal Range”
Standard labs report testosterone as normal at 300–1,000 ng/dL. A man with 320 ng/dL may be told he’s “normal” — but that reference range reflects the average of an aging, largely sedentary population. At Provena, we look at symptoms alongside labs, evaluate free testosterone (not just total), SHBG, LH, FSH, and estradiol, and ask: what level does this person actually feel best at?
Testosterone Replacement Therapy: What the Evidence Shows
For men with confirmed hypogonadism, TRT is one of the most well-studied interventions in hormone medicine. The TRAVERSE trial (2023) — a large randomized controlled trial — found TRT in hypogonadal men did not increase the risk of major cardiovascular events compared to placebo, substantially revising older concerns about cardiovascular risk.
Key TRT considerations: comprehensive baseline labs including free testosterone, SHBG, LH, FSH, estradiol, and PSA; assessment of fertility intentions (TRT suppresses natural sperm production); lifestyle optimization first (sleep, exercise, diet, stress); and ongoing monitoring of hematocrit, estradiol, PSA, and symptoms.
Q: Can I raise testosterone naturally? Yes, meaningfully — through resistance training, optimized sleep, stress reduction, fat loss, and dietary improvements. For many men in the lower-normal range, these interventions alone produce significant improvements.