The Dr. Hyman Show

Episode: Why Men’s Fertility Is Collapsing and What It Means for Our Future

Guest: Dr. Michael L. Eisenberg
Host: Dr. Mark Hyman
Date: January 28, 2026

Episode Overview

In this illuminating episode, Dr. Mark Hyman sits down with Dr. Michael Eisenberg, professor of urology at Stanford and a leading researcher in men’s reproductive health, to explore the alarming global decline in male fertility. Together, they dissect potential causes—ranging from metabolic dysfunction, environmental toxins, lifestyle shifts, and beyond—and discuss what this means for the future of human health. Dr. Eisenberg shares cutting-edge research, practical advice, and hope for interventions that can reclaim hormonal and reproductive well-being.

Key Discussion Points & Insights

1. The Alarming Decline in Men’s Fertility

• Men’s fertility is plummeting globally: Semen quality and sperm counts have declined over the last 50 years across diverse populations.
  • “Over the last half century or so, I think there's been a rise in male infertility and specifically semen quality has gone down.” — Dr. Eisenberg (00:00)
• Infertility: Not just a women’s issue: Around half of infertility cases involve a male factor, yet men are often overlooked in fertility evaluations.
  • “Maybe a quarter of a third of the time a man has never evaluated. He's just sort of bypassed. Not even a semen analysis, no evaluations done.” — Dr. Eisenberg (05:40)

2. Sperm Quality as a "Vital Sign" of Men’s Health

• Semen quality predicts long-term health and mortality
  • “Where their semen quality was when they were 40, predicted their death, you know, 30, 40 years later.” — Dr. Eisenberg (00:26)
  • Low sperm count is a stronger predictor of poor health outcomes than obesity or smoking.
  • “Having a low sperm count and not smoking is worse than smoking and having a high sperm count.” — Dr. Eisenberg (23:43)

3. Causes of Declining Male Reproductive Health

Metabolic Health

• Obesity & Insulin Resistance: Strongly tied to low testosterone and sperm quality.
  • “The bigger a guy's belly, the worse his sperm was...your sperm quality and function are going to be bad.” — Dr. Hyman (00:31, 07:26)
• Sedentary Lifestyles: Contributes to both hormonal and reproductive dysfunction.

Environmental Exposures

• Endocrine Disruptors: Ubiquitous in plastics, pesticides, and certain cosmetics.
  • “Microplastics are getting more and more attention recently...that's found in most testicles of men.” — Dr. Eisenberg (00:39, 09:42)
• Ubiquity and Limitations of Avoidance: While total avoidance is impossible, minimizing exposures (glass food storage, EWG resources, avoiding plastics in microwaves) can help.
  • “The best you can do is sort of avoid them.” — Dr. Hyman (14:35–16:15)
• Household Toxins: Beauty products, cleaning products, and processed foods are common exposure routes.

Accelerating Pace

• “What's really interesting is if you look over the last 20 years, the decline has been accelerating. So whatever's causing it is potentially getting worse.” — Dr. Eisenberg (09:05)

4. Testosterone Crisis and Generational Decline

• Testosterone has dropped significantly in recent decades, even after adjusting for age
  • “If you look at data age for age, the testosterone levels have gone down more recently. It is accelerating. It's really incredible.” — Dr. Eisenberg (00:47, 18:24)
  • Lifestyle and environmental exposures are implicated in this shift.

Sperm Quality, Genetics, and Male Aging

Advanced Paternal Age

• Older age: Increases mutations in sperm DNA, which can affect neurodevelopmental and behavioral outcomes in offspring.
  • “As fathers get older... we see higher risk of miscarriage, preterm birth, all those things.” — Dr. Eisenberg (29:06)
• Paternal contributions: Father’s age and health also influence placenta development and pregnancy outcomes via epigenetic changes.

Epigenetics

• “You know, all these diseases are not likely going to mutate our DNA, but they basically affect the covering and the expression of some of the DNA. This is so called epigenetics.” — Dr. Eisenberg (30:15)

Optimizing Male Fertility and Sexual Health

Actionable Lifestyle Interventions

• Diet & Exercise: Maintain healthy weight, strength training boosts testosterone; exercise outdoors for extra benefit.
  • “Sunlight exposure... increased about 10 points for every additional hour you spent outside.” — Dr. Eisenberg (33:32)
• Minimize exposures: Avoid plastic containers, pesticides (organic when possible), heat to groin area (saunas, hot tubs, laptops), and EMF/radiation from devices.
• Supplements and Antioxidants: Nutrients like omega-3s, CoQ10, zinc, selenium, lycopene, spermidine, folate, and N acetylcysteine shown to improve sperm quality.
  • “There’s strong data behind them... large Cochrane meta-analyses.” — Dr. Eisenberg (38:51)

Hormone Therapy Cautions

• Testosterone supplementation: Only for men with confirmed low testosterone and symptoms; can cause infertility by suppressing sperm production.
  • “I'm kind of shocked at the number of young men who are taking it... Infertility is the result of him taking testosterone, which shuts off your sperm production.” — Dr. Hyman (57:00)
  • Recovery after stopping testosterone is variable and not guaranteed, especially after long-term or anabolic steroid use.

Addressing Erectile Dysfunction

• Primarily vascular, not hormonal: Linked to same metabolic and lifestyle risks as heart disease.
  • “People think about like low testosterone as a big driver of erectile dysfunction, but it probably contributes about 5%.” — Dr. Eisenberg (47:05)
• Treatment options: Lifestyle, medications (Viagra/Cialis), local treatments (suppositories, injections), vacuum devices, energy therapies (shockwave), and surgical implants.
  • “As long as you have a penis, we can always make it hard.” — Dr. Eisenberg (52:12)

Memorable Quotes & Moments

• Sperm count as future-predictor:
  “Where their semen quality was when they were 40, predicted their death, you know, 30, 40 years later.” — Dr. Eisenberg (00:26)
• On stress and hormones:
  “As cortisol and stress goes up, we see lower testicular function. So we can see sperm counts go down, testosterone levels go down.” — Dr. Eisenberg (41:57)
• “Having a low sperm count and not smoking is worse than smoking and having a high sperm count.” — Dr. Eisenberg (23:43)
• Endocrine disruptor omnipresence:
  “Plastics... should be inert, but there's lots of other chemicals or plasticizers that go into that and they leach out in water bottles, for example.” — Dr. Eisenberg (12:17)

Rapid-Fire Myth-Busters (73:43–78:55)

• Cell phones in pocket: Probably okay, but back pocket or farther from groin is better.
• Boxers or briefs: No clear advantage—breathability is helpful; wear what's comfortable.
• Saunas/hot tubs: Can acutely lower sperm count—avoid for 2–3 months prior to trying to conceive.
• Laptops on lap: Raises scrotal temperature—better to keep on a desk.
• Time of year: Sperm counts mildly higher in cooler months.
• Cycling: Over 5 hours/week can reduce sperm quality and increase risk for erectile issues.
  Suggestion: Stand up frequently, try alternative saddle designs (vseat).
• Alcohol: Harmful above ~20 drinks/week or if genetically sensitive ("Asian flush").
• Sedentary lifestyle: Reduces sperm quality—stay active.
• Sleep: Optimal range is 7–9 hours; too little or too much both impair sperm quality.
• Stress: Major negative impact—actively seek stress reduction techniques.

Notable Timestamps

• [00:00–06:16] — The scope of the male fertility crisis and overview
• [09:42–14:35] — Environmental toxins and microplastics
• [18:05–24:00] — Testosterone’s generational decline and metabolic health
• [25:11–30:15] — Older paternal age, sperm DNA mutations & risk to offspring
• [32:00–41:00] — Real-world advice: lifestyle, tests, supplements
• [45:48–48:26] — Erectile dysfunction: causes and treatments
• [50:47–54:36] — Therapy options: pills, injections, devices, energy therapies, implants
• [57:00–64:12] — Testosterone replacement therapy: indications, risks, fertility impact
• [73:43–78:55] — Rapid-fire FAQ: heat, alcohol, cycling, sleep, stress
• [79:00] — Resources: Dr. Eisenberg’s lab, Swim Club supplement, research

Final Takeaways & Practical Advice

• Fertility reflects overall men’s health: Sperm analysis should be considered a vital sign and routine metric, not just for those seeking children.
• Many risk factors are modifiable: Diet, exercise, environmental exposures, and stress can all be optimized—with real, measurable effects on hormones and fertility.
• Tests matter: Men’s reproductive health is frequently overlooked—proactive evaluation and bloodwork (including for testosterone, free T, estrogen) are essential.
• Don’t ignore early warning signs: Erectile dysfunction and low libido are often the earliest clues of wider vascular or metabolic dysfunction.

Empowerment through information is key—you can take action for your own health and for future generations.

Resources & Where to Learn More

• Dr. Eisenberg’s Research: Eisenberg Lab at Stanford (search online)
• Male Fertility Supplement: swimclub.co
• Environmental Toxins Resource: EWG.org, Skin Deep app
• Hormone, Fertility, and Health Testing: functionhealth.com
• Podcast Host: Dr. Mark Hyman (@drmarkhyman on all platforms)

If you found this summary valuable, be sure to check out the full episode for an even deeper dive—and share this with anyone who cares about men’s health or planning a healthy family!