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Last Updated: 12.06.23

How to Optimize Fertility in Males & Females

Dr. Huberman explores human fertility, egg and sperm generation, the ovulatory cycle, and optimizing reproductive health for vitality and longevity. Discusses nutrition, behavior, supplements, prescriptions, and surprising lifestyle choices. Provides science-​​based protocols for conception and improving overall health, regardless of age.

Key Takeaways

High level takeaways from the episode.

By understanding fertility and fertilization, you can maximize your vitality and longevity.

Over the last 100 years, the onset of puberty in females has occurred earlier

  • Example: In the US, the average age of puberty onset in females was 14 in 1900, and 11 in 1990

Low body fat stores in children may contribute to delayed puberty

  • Accumulation of body fat releases leptin, a hormone that can trigger puberty
  • Earlier puberty in females may be due to increased body fat at younger ages

Earlier onset of puberty not necessarily detrimental

  • Various factors contribute to earlier onset, including environmental and genetic factors

Exposure to the scent of a reproductively competent male can trigger earlier puberty in females

  • This effect can be partially buffered by the presence of the scent from the female’s biological father

Testosterone can stimulate hair growth. Estrogen can enlarge breast tissue cells. Prolactin can control milk production and secretion, and affect libido in males.

The average female reproductive cycle is 28 days long, but can range from 21 to 35 days

  • Consistency in cycle length is more important than the exact number of days
  • No causal relationship between the lunar cycle and the menstrual cycle

Increase in libido for some women 4–5 days prior to ovulation

  • Spike in FSH, LH, and androgens (DHEA, testosterone) can trigger libido

Some women experience malaise during luteal phase, associated with depletion in estrogen levels.

Avoid hot tubs, hot baths, and saunas if trying to conceive in the next 90 days. Heat exposure can mutate and disrupt developing sperm and kill sperm. Other factors that can increase scrotal temperature

  • Big thighs (muscular or overweight)
  • Sitting for long periods
  • Seat heaters in cars

No significant difference in sperm quality between boxers, briefs, or no underwear.

Improving mitochondrial function can lead to better egg and sperm quality.

  • Mitochondria are crucial for the separation of chromosomes in egg and sperm cells

Heavy drinking, smoking, and regular cannabis use can negatively impact semen quality.

Ideal sperm parameters for fertilization:

  • More than 15 million sperm per milliliter of ejaculate

Sperm counts seem to be declining, reasons unclear.

Faster swimming sperm and more far along the ovulatory trajectory of the egg increase the probability of successful fertilization

  • Proximity to the implantation zone of the uterus is crucial

Metaanalysis and reviews correlate smartphones in pockets with diminishing sperm counts.

Dr. Shana Swan’s work on phthalates and BPAs

  • Endocrine disruptors found in pesticides and printed receipts
  • Reductions in testosterone and disruptions to Sertoli cells and androgen-​​binding protein
  • Impact on sperm counts still debatable

Clinicians prefer ejaculate volume of more than 2 mL for conception.

  • Frequency of ejaculation plays a role in volume of ejaculation and sperm concentration

Some women can accurately estimate ovulation timing within a couple of hours

  • Interoceptive awareness: awareness of sensory events within the body
  • Sensory endings within the ovary may allow some women to feel ovulation

Different ways to track ovulation:

  • Temperature method: measuring intravaginal temperature for changes consistent with ovulation
  • Using apps: inputting temperature information and marking the onset of menstruation

Some commercially available lubricants can be detrimental to sperm health even without spermatocide.

For females 30 years old or younger, 20% chance of successful fertilization and pregnancy on the first month of attempting

  • Typical advice from OBGYN: attempt to conceive over a period of six months

Age plays a significant role in the probability of getting pregnant. Probability of getting pregnant on any one attempt to conceive:

  • 20% for women 30 years old or younger
  • 18% for women 31 to 33 years old
  • 11% for women 34 to 37 years old
  • 5% for women 38 to 39 years old
  • 1–3% for women 40 years old or older

OBGYNs typically advise trying for a certain number of months based on age before seeking medical intervention.

Miscarriage rates increase with age:

  • 25% of successful fertilizations lead to miscarriages for women 35 years or older
  • 50% for women 40 years or older
  • Miscarriages can arise from genetic defects, issues in the uterus, or issues with sperm
  • Chromosomal abnormalities can be a common reason for miscarriages

Women can evaluate their fertility by asking their OBGYN about AMH levels and the number of follicles they have in a given month.

  • More follicles generally indicate a higher ovarian reserve and higher fertility
  • Helps in planning for future conception

Common misconception: only one sperm needed for fertilization

  • In reality, a large number of quality sperm needed for a high probability of successful fertilization

Age of father and sperm can impact pregnancy outcomes (e.g., increased risk of autism)

  • Men should get sperm analyzed every five years and consider freezing younger sperm
  • Sperm analysis is relatively inexpensive

Excessive stress can negatively impact fertility and pregnancy.

Get an STI check when trying to conceive or evaluating fertility

  • Chlamydia, in particular, can increase the probability of miscarriage and negatively impact male reproductive health

Severe viral illnesses can negatively impact sperm and egg quality

  • For men, a viral illness in the previous 70–90 days can diminish sperm count and quality
  • For women, a viral illness in the previous 30 days can impact egg quality
  • Viral infections during pregnancy, such as influenza, may have correlations with negative mental health outcomes in offspring (e.g., schizophrenia)
  • Consult with an OBGYN if you have had a viral infection while trying to conceive or during pregnancy

Taking testosterone from an external source can reduce or eliminate spermatogenesis.

No evidence to support theories about sexual positions or thoughts during ejaculation affecting sex determination.

It is recommended to avoid cannabis use when trying to conceive and during pregnancy.

Tilting the pelvis back by about 20 degrees for 15 minutes post-​​ejaculation may increase the probability of fertilization.


Science-​​based tools and supplements that push the needle.

Things to Avoid to Optimize Sperm Quality


Optimal Intercourse Strategy for Fertilization


Alcohol and Fertility


Fertility Recommendations for Men and Women


L‑carnitine Supplementation for Fertility



We recommend using this distillation as a supplemental resource to the source material.

  • How to Optimize Fertility in Males & Females

    Huberman Lab #109

    Dr. Huberman delves into human fertility, egg/​​sperm generation, the ovulatory cycle, and optimizing reproductive health for vitality and longevity. Covers science-​​based protocols and surprising lifestyle choices.

Full Notes

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