Male fertility: optimizing reproductive health, diagnosing and treating infertility, and navigating testosterone replacement therapy | Paul Turek, M.D.

Peter Attia

Jun 2, 2025

Episode description

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This is part one of a two-part mini-series on fertility and reproductive health, with next week's guest, Dr. Paula Amato, focusing on the female side of the equation. Paul Turek is a world-renowned expert in male fertility and reproductive health, the founder and medical director of the Turek Clinic, and host of the Talk with Turek podcast. In this episode, Paul explores the topic of male fertility, offering a detailed look at the complex and highly coordinated process of conception and the many challenges sperm face on their journey to fertilizing an egg. He shares fascinating insights into how sperm work together to navigate the female reproductive tract, how environmental factors like heat, stress, and toxins impact sperm quality, and what men can do to improve their reproductive health. Paul also dispels common myths about testosterone replacement therapy and its effects on fertility, providing strategies for preserving fertility while on TRT. The episode also highlights cutting-edge advances in reproductive medicine, from genetic testing and sperm sorting to emerging treatments for infertility.

We discuss:

The incredibly complex and hostile journey sperm must take to fertilize an egg [3:00];
How sperm are made: meiosis, genetic variation, and the continuous renewal influenced by environmental factors [9:00];
The built-in filter that weeds out genetically abnormal sperm [14:45];
How sperm are finalized in form and function: tail formation, energy storage, and chemical sensing abilities [18:30];
How to optimize conception through the timing of sex, ejaculation frequency, and understanding the sperm lifecycle [26:30];
Male infertility and Paul’s diagnostic approach: detailed history, a physical exam, and identifying red flags [33:30];
Viral infections that can affect the testes and potentially lead to sterility [40:30];
Semen analysis: morphology, motility, and hormonal clues to male fertility [45:45];
Effects of medication, microplastics, stress, and exercise on fertility [57:15];
Testosterone replacement therapy (TRT) and male fertility [1:06:00];
Restoring fertility after prolonged use of exogenous testosterone [1:25:00];
Effects of heat and cold exposure

Mindsip insights from this episode:

Limit hot tub use to protect sperm count

Spending 20 minutes in a 104°F hot tub three times a week is a 'lethal dose' that can make a man's sperm count drop to zero.

#fertility

Reframe autism as a step in human evolution

The rise in neurodevelopmental conditions like autism, linked to paternal age, may not be a disease but rather the next step in human evolution.

#autism

#evolution

Front-load intercourse before ovulation for higher conception rates

About 80% of natural conceptions occur when intercourse happens before ovulation, as the egg only survives for about eight hours while sperm can wait for days.

#fertility

Limit extreme exercise to protect fertility

A study found that extreme exercise, defined as two hours a day at 80% of VO2 max, caused sperm counts to fall by 40%.

#exercise

#fertility

Understand how fathers transmit environmental stress through sperm

Sperm are the primary drivers of human evolution and are more likely than eggs to pass on transgenerational epigenetic changes from environmental stressors.

#epigenetics

#genetics

Choose newer TRT forms to preserve fertility

Newer, more frequently delivered forms of testosterone like the oral twice-a-day pill (Jatenzo) may be less suppressive and allow men to maintain sperm counts.

#fertility

#TRT

Understand sperm teamwork to enhance fertilization success

The first waves of sperm act as a phalanx, sacrificing themselves to deactivate the female immune system so that later sperm can get through.

#fertility

#sperm

Consider long-term TRT risks for irreversible effects

After 5 to 10 years of continuous exogenous testosterone use, the damage to natural sperm and testosterone production may become irreversible.

#testosterone

#TRT

Add low-dose HCG to testosterone therapy to preserve fertility

To preserve fertility while on testosterone replacement therapy, you can add low-dose HCG (250-500 units twice a week) to maintain testicular sperm production.

#fertility

#testosterone

Utilize sperm's olfactory sense to detect egg presence

Sperm have an olfactory sense that can detect follicular fluid from an egg at a concentration of one part per billion.

#fertility

#sperm

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