Sperm quality is heavily modifiable by lifestyle — heat from laptops, saunas, and front-pocket phones each reduce sperm count and motility, and a 60–90 day abstinence window before a conception attempt determines whether the sperm cohort is healthy.
2
Mitochondrial function is the central bottleneck for both egg and sperm quality: L-carnitine, CoQ10, and exercise all work primarily by supporting the mitochondria that power chromosomal segregation in eggs and forward swimming motility in sperm.
3
Age-dependent egg quality drives fecundability more than any other single variable — a 20% per-cycle conception rate at age 30 drops to roughly 5% by age 38–39, making early AMH and antral-follicle-count testing one of the highest-leverage things a woman can do.
4
The same interventions that optimize fertility — quality sleep, limiting alcohol to two drinks per week or zero, avoiding cannabis, controlling body fat, and targeted supplementation — are functionally identical to the interventions that optimize vitality and longevity.
Protocols
Concrete recipes — what, when, how much, and why
8 items
Avoid heat to testicles for 90 days before TTC
WhatEliminate or drastically reduce hot tub use, sauna sessions, seat heaters in cars, and laptop-on-lap use during the 90 days before a conception attempt. Do not carry a smartphone in the front pocket.
WhenThe full 90-day window before any attempt to conceive (60 days of spermatogenesis + ~30 days of transport maturation).
DoseContinuous avoidance for 90 days. If sauna is used, bring an ice pack and keep scrotal tissue cool throughout the session.
For whomAny male trying to conceive, and any male wishing to maintain optimal testosterone and sperm quality.
WhyThe testes require a temperature approximately 2°C cooler than core body temperature for healthy spermatogenesis. Sustained heat from any source mutates developing sperm DNA, kills mature sperm, and produces twitcher-type (non-forward-progressing) sperm even at temperatures that are not subjectively hot.
CaveatsBoxers versus briefs makes minimal difference because the cremaster muscle actively regulates testicular temperature regardless of underwear type. The primary concerns are external heat sources (hot tubs, saunas, car seat heaters, laptops, phones).
Huberman notes that large upper thighs — whether from obesity or high muscle mass — can also chronically elevate scrotal temperature through simple anatomical compression. Deliberate cold exposure (1–3 minutes daily cold shower or cold immersion) benefits sperm quality not because cold directly improves spermatogenesis but because it reduces overall scrotal temperature and may also improve testosterone by increasing dopamine and norepinephrine. 'Snowball' scrotal cooling garments are commercially available for targeted cooling.
Mechanism
Spermatocytes and mature sperm are temperature-sensitive; elevated heat disrupts mitochondrial function in the sperm mid-piece and impairs spindle-mediated chromosomal segregation. Both RF waves from phones and direct heat suppress Leydig cell testosterone production, compounding the damage.
If you are hoping to conceive in the next 90 days... you definitely want to avoid exposing your testicles — that is, your scrotum — to elevated temperatures. So that means definitely avoiding hot tubs, definitely avoiding hot baths.
L-carnitine supplementation to improve egg and sperm quality
WhatTake 1–3 grams per day of L-carnitine in capsule or liquid form. Co-supplement with 600 mg per day of garlic extract to offset TMAO elevation.
WhenBegin at least 30 days before a planned conception attempt; can be continued throughout the attempt period.
Dose1–3 g/day L-carnitine for a minimum of 30–60 days; 600 mg/day garlic extract concurrently. Can be taken with or without food, split or all at once.
For whomBoth men and women seeking to conceive; also relevant for anyone wishing to optimize fertility as a proxy for general cellular health.
WhyL-carnitine is directly involved in mitochondrial lipid metabolism, which powers the spindle apparatus that segregates chromosomes in eggs (diploid to haploid transition) and drives the flagellar mid-piece motor in sperm. Clinical studies show significant improvements in egg chromosomal arrangement, sperm forward motility, and sperm morphology within 30–60 days.
CaveatsOral L-carnitine elevates TMAO (trimethylamine N-oxide), which can increase arterial stiffness. Garlic extract (allicin) reliably offsets this effect. IV or intravenous L-carnitine bypasses the TMAO issue but is impractical for most people.
Huberman emphasizes that even people who are successfully conceiving naturally might choose L-carnitine to further improve the chromosomal quality of the resulting embryo — an argument that extends beyond fertility into offspring health optimization. The 1–3 gram range is supported by peer-reviewed studies in humans.
Mechanism
L-carnitine shuttles long-chain fatty acids across the inner mitochondrial membrane for beta-oxidation. In eggs, healthy mitochondria are critical for spindle formation and correct chromosomal segregation during meiosis. In sperm, mitochondria are packed in the mid-piece and generate the ATP that powers flagellar movement.
1 to 3 grams per day of capsule form L-carnitine is what's been suggested to improve egg quality and sperm quality... When taken for a period of 30 to 60 days, it does seem to significantly improve all the parameters that have been discussed for egg quality and sperm quality.
Also said
“One important note — if you are going to take L-carnitine in oral form, in capsule form, it can increase something called TMAO. TMAO can cause stiffening of the arteries... One way to offset the increases in TMAO caused by oral L-carnitine is to take 600 milligrams of garlic per day.”— The safety caveat and its fix — most people citing L-carnitine for fertility miss the TMAO/garlic co-supplementation requirement.
CoQ10 supplementation for mitochondrial support of egg and sperm
WhatTake 100–400 mg per day of coenzyme Q10 with a fat-containing meal, preferably dinner.
WhenOngoing, ideally started several months before a conception attempt.
Dose100–400 mg/day; taken with a fat-containing meal (fat improves absorption). Blood levels should ideally fall between 0.5–2.5 on standard assay.
For whomBoth men and women; routinely prescribed by fertility specialists for patients undergoing IVF as well as for natural conception attempts.
WhyCoQ10 supports mitochondrial electron transport chain function, improving cellular energy production. As in the case of L-carnitine, healthy mitochondria are the proximate driver of chromosomal segregation in eggs and forward motility in sperm.
Huberman notes that CoQ10 levels are measurable in standard blood tests and that levels outside the 0.5–2.5 range indicate likely deficiency. Many fertility docs now include CoQ10 in their standard pre-conception supplement protocol alongside L-carnitine and omega-3s. The fat-containing meal requirement is practical rather than arbitrary — CoQ10 is lipophilic and absorption is substantially higher when taken with dietary fat.
Mechanism
CoQ10 (ubiquinol/ubiquinone) is an essential electron carrier in the mitochondrial respiratory chain (Complex I–III). Without sufficient CoQ10, mitochondrial ATP production is impaired, which directly compromises spindle function in eggs and flagellar movement in sperm.
The coenzyme Q10 dosages that are most often suggested and that you'll observe in the peer-reviewed research literature — on humans, I should add — is 100 to 400 milligrams per day. And the coenzyme Q10 is taken generally with a meal and ideally a meal that contains fat.
Myo-inositol (+ D-chiro inositol for women) to improve insulin sensitivity and egg/sperm quality
WhatTake 1–5 g/day of myo-inositol. Women also add D-chiro inositol at 1/25 to 1/40 the myo-inositol dose. Take in the second half of the day as it is mildly sedating.
WhenOngoing supplementation; begin before conception attempts and continue during the attempt period (not during pregnancy without OB/GYN guidance).
DoseMyo-inositol: 1–5 g/day. D-chiro inositol for women: dose = myo-inositol dose in mg divided by 25 to 40. Start at 1–2 g myo-inositol and titrate up. Take later in the day.
For whomBoth men and women for insulin sensitivity and mitochondrial support. Women with PCOS or elevated androgens should particularly prioritize the D-chiro inositol component.
WhyMyo-inositol improves insulin sensitivity, reducing the hyperinsulinemia that disrupts the hormonal axis driving ovulation and spermatogenesis. Improved insulin sensitivity also supports mitochondrial health. D-chiro inositol additionally modulates androgen levels, making it particularly useful for PCOS or any woman with elevated androgens impairing ovulation.
CaveatsMyo-inositol is mildly anxiolytic and sedating at higher doses (hence the evening-dosing recommendation). Start low and titrate. Not recommended during pregnancy without medical supervision.
Huberman separately uses 900 mg myo-inositol nightly as part of his sleep supplement stack; he notes the fertility and sleep benefits come from the same mechanism at different doses. The 1/25–1/40 ratio for D-chiro inositol relative to myo-inositol is derived from the natural ratio of these two inositol isomers in human plasma. Women with polycystic ovarian syndrome tend to have an abnormally low D-chiro-to-myo ratio, and correcting it reduces androgen excess and restores more regular ovulation.
Mechanism
Inositol isomers serve as second messengers in insulin receptor signaling; improved signaling reduces compensatory hyperinsulinemia that otherwise suppresses SHBG (raising free androgens) and disrupts GnRH pulsatility.
Myo-inositol is often recommended for people that want to improve egg and sperm quality because of the way that it can positively impact insulin sensitivity... 1 to 5 grams per day of myo-inositol is what's suggested for both men and women wishing to improve egg health and sperm health.
Omega-3 EPA supplementation at 1 g/day minimum for fertility and sperm quality
WhatTake enough omega-3 capsules or liquid to deliver at least 1 gram per day of the EPA form specifically (not total omega-3 content). Read labels — a '1,500 mg omega-3' capsule may contain only 750 mg EPA.
WhenOngoing; EPA is beneficial for general health and fertility throughout the pre-conception and attempt periods.
DoseMinimum 1 g EPA/day; optimal range 1–3 g EPA/day. Liquid form is most cost-effective; capsules are more convenient. Can be taken with any meal.
For whomBoth men and women. Particularly important for anyone not regularly consuming fatty fish (sardines, anchovies, salmon with skin).
WhyOmega-3 fatty acids (EPA in particular) support cell membrane fluidity, mitochondrial function, and the resolution pathway of inflammation. Fertility docs commonly prescribe omega-3s for both egg and sperm quality alongside CoQ10 and L-carnitine.
CaveatsRead labels carefully — the total omega-3 milligrams on the front of the label are not the same as EPA milligrams, which are listed on the Supplement Facts panel. Most people need 2–3 high-potency capsules per day to reach 1 g EPA.
Huberman explains that plant-based omega-3 sources provide ALA, which the human body converts to EPA and DHA at very low efficiency — making supplementation with fish oil, krill oil, or algal oil generally necessary for meaningful EPA delivery. He places omega-3 in his 'foundational supplement' category.
Enough of those that you're getting at least 1 gram per day of the EPA form of omega-3, so at least 1 gram per day and as high as 2 or even 3 grams per day of the EPA form. So you'll need to look at the packaging because oftentimes it'll say high potency omega-3. It'll say 1,500 milligrams of omega-3. But that's not 1,500 milligrams of the EPA form.
Zinc 120 mg twice daily with food for male testosterone and sperm count
WhatMales take approximately 120 mg elemental zinc twice per day, always with full meals to prevent nausea. Females should meet RDA but do not need supraphysiological doses.
WhenDuring the 90-day pre-conception period and throughout the attempt period for males.
Dose120 mg twice per day (240 mg/day total) with full meals. This is a high dose — do not take on an empty stomach.
For whomMales wishing to increase sperm count, testosterone, or both. Not systematically studied in females at supraphysiological doses.
WhyZinc is uniquely enriched in the testes and serves as a cofactor for androgen-binding protein (ABP), the Sertoli cell product required for spermatogenesis. Studies show this dose significantly increases testosterone, dihydrotestosterone, and sperm count.
CaveatsZinc at this dose must be taken with a full meal — even 15–30 mg on an empty stomach can cause intense nausea. Chronic very high zinc intake can interfere with copper absorption.
Huberman cites research dating to the observation in 1921 that zinc levels in fish testes spike during breeding season. The paper he references — 'Effect of Zinc Administration on Plasma Testosterone, Dihydrotestosterone, and Sperm Count' (1981) — found increases in testicular size as well. Zinc does not appear to affect GnRH or prolactin, suggesting a targeted gonadal action.
Mechanism
Zinc is a required cofactor for androgen-binding protein (ABP) synthesis by Sertoli cells. Without adequate ABP, intratesticular testosterone cannot be maintained at the ~100x concentration needed to drive spermatogonial maturation into healthy sperm.
Zinc dosages that are pretty high of about 120 milligrams taken twice per day — that's quite a lot — with meals can significantly increase testosterone and dihydrotestosterone... zinc in both animals... and in humans, strongly impacts the enzymatic functions in the testes, including the function of androgen-binding protein.
Optimize intercourse timing: 48–72h abstinence before ovulation, maximize ejaculations on ovulation day
WhatAbstain from ejaculation for 48–72 hours before the expected day of ovulation to maximize sperm concentration. Then have intercourse with ejaculation on the day prior to ovulation and maximally on ovulation day itself.
WhenApplied during each monthly attempt to conceive, timed to the ovulatory window.
Dose48–72 hour pre-ovulation abstinence window. Ovulation lasts approximately 24 hours; sperm survive in the female reproductive tract for 3–5 days.
For whomAny couple using timed intercourse as a conception strategy.
WhyEach successive ejaculation within 12–24 hours dramatically reduces the concentration of high-quality sperm per milliliter. The 48–72 hour abstinence period maximizes the concentration and quality of the first ejaculate after the window.
CaveatsWomen with irregular cycle lengths should use temperature tracking, LH-surge ovulation predictor kits, or cervical mucus monitoring. Commercial lubricants frequently impair sperm motility — use fertility-specific lubricants.
Huberman discusses expert disagreement on post-coital pelvic positioning: some OB/GYNs recommend the woman lie on her back with pelvis elevated ~20 degrees for 15 minutes after ejaculation; others say sperm motility makes positioning irrelevant. Given zero cost and potential upside, Huberman endorses the 15-minute tilted-pelvis approach.
What everyone agrees on is that a period of abstinence ranging from 48 to 72 hours prior to an ejaculation increases the concentration of high-quality sperm within that first ejaculation to occur after the abstinence period.
Get AMH and antral follicle count measured early — not just when trying to conceive
WhatWomen should get anti-Müllerian hormone (AMH) blood test and antral follicle count (ultrasound) in their 20s–30s as a baseline, repeated every few years. Men should get sperm analysis every 5 years and consider sperm freezing.
WhenStart in early-to-mid 20s regardless of current fertility intentions. Repeat before any serious conception planning.
DoseAMH is a single blood draw. Antral follicle count is a short in-office ultrasound. Both should be measured across several months to determine average follicle count.
For whomAll women of reproductive age, especially those not currently planning children but who might want them in the future. All men: sperm analysis every 5 years.
WhyThe ovarian reserve strongly predicts the natural conception window. Having a baseline in one's 20s allows meaningful comparison in the 30s or 40s, enabling informed decisions about egg freezing, embryo banking, or timing natural conception.
CaveatsLow AMH or antral follicle count does not eliminate fertility — some women with few follicles conceive readily — but it indicates a shorter natural conception window and warrants earlier medical consultation.
Huberman reports that multiple OB/GYNs he interviewed expressed the same regret: patients only discovered low ovarian reserve in their late 30s or 40s when options were much more limited. Earlier knowledge allows informed decisions about egg freezing or attempting natural conception sooner.
I cannot tell you how many women that I've spoken to and how many OB/GYNs... wish that they had done this earlier... the earlier and more frequent that women do this procedure of measuring AMH and measuring their follicle count, the higher the probability that they will eventually have a successful fertilization and pregnancy when they seek to do so.
What's new
Personal practice updates, fresh positions, predictions
6 items
Smartphones in front pockets reduce sperm count regardless of usage duration
~3 h 10 min
A 2021 meta-analysis of 18 studies (4,280 samples) found that sperm quality declines from the moment someone begins using a mobile phone — and, critically, the reduction is not time-dependent. Even minimal phone use near the groin impairs sperm.
Why this matters: Prior guidance focused on limiting phone use to four-plus hours per day. The new finding is that there is no safe carry-in-pocket threshold: any proximity appears to reduce sperm count and motility.
Background
RF electromagnetic waves at 80–2,200 MHz are absorbed by human tissue; the Leydig cells of the testes are particularly vulnerable, and phone heat alone — even when the device doesn't feel warm — shifts scrotal temperature enough to affect spermatogenesis.
Huberman references the paper 'Effects of Mobile Phone Usage on Sperm Quality — No Time-Dependent Relationship on Usage: A Systematic Review and Updated Meta-Analysis' (2021). The mechanism is dual: RF electromagnetic waves disrupt Leydig cell function (reducing intratesticular testosterone, the primary driver of spermatogenesis) and localized heat further impairs sperm development. Both effects are independent and additive. Huberman's practical recommendation: if you are trying to conceive, avoid front-pocket carry altogether, and ideally keep the phone as far from the groin as possible at all times.
The data indicate that sperm quality declines when people start using a mobile phone. So from the point they start using a mobile phone, regardless of the usage time — this is important. It used to be thought that it was four hours a day or more of holding your phone or having that phone close to your body was going to diminish sperm quality. It turns out that it's not related to usage time.
Also said
“These phones emit a radio frequency electromagnetic waves at a low level between 80 and 2,200 megahertz that can be absorbed by the human body... and have potential adverse effects on brain, heart, endocrine system, and reproductive function.”— Establishes the mechanism — RF waves are absorbed and act on endocrine tissues including the testes.
A single binge-drinking episode damages sperm for 60–90 days
~2 h 20 min
One night of five to six drinks significantly raises reactive oxygen species in semen and disrupts the entire cohort of sperm being developed over the following 60–90 day spermatogenesis cycle — not just the sperm present at the time of drinking.
Why this matters: Most men assume that a hangover resolves within 24–48 hours and sperm are unaffected. The reality is the damage propagates through an entire spermatogenesis window, making pre-conception alcohol avoidance a several-month commitment.
Background
Alcohol increases ROS throughout seminal fluid and also disrupts GnRH secretion from the hypothalamus via the GABA receptor pathway, blunting the hormonal axis that drives spermatogenesis.
For women, the same binge-drinking event degrades not just the egg that ovulates that month but the entire pool of follicles leaving the ovarian vault during that cycle, because all are exposed to the same oxidative milieu. Huberman also notes that even the timing of the binge relative to menstruation doesn't protect eggs: alcohol disrupts GnRH, FSH, and LH signaling regardless of cycle phase. His summary recommendation: two drinks per week is the absolute ceiling for anyone trying to conceive, and zero is always better.
If you are a male, what that means is that's going to impact the quality of your sperm and greatly decrease the likelihood of successful fertilization and/or healthy pregnancy over the period of that entire spermatogenesis window, which is, as we talked about before, 60 to 90 days.
One in five infertility cases is attributable to sperm — not egg
~1 h 50 min
Huberman highlights a widely underappreciated statistic: in 20% of couples experiencing fertility challenges, the issue traces to sperm quality or quantity rather than egg quality. Sperm analysis remains underutilized because men assume fertility problems are primarily a female biology issue.
Why this matters: Framing fertility challenges as primarily a female problem leads couples to spend years and money on egg-focused interventions while the actual limiting factor — sperm — goes unaddressed.
Huberman recommends all men get a sperm analysis at least once every five years and consider freezing sperm in their 20s or early 30s at nominal cost. Beyond simple count and motility, DNA fragmentation analysis can detect sperm that appear normal morphologically but cannot deliver intact genetic material. The urologists Huberman consulted stress that because semen analysis is inexpensive relative to IVF, there is no rational reason to defer it.
One in five couples that have issues with fertility, the issue ends up falling on the biology that is the quality of the sperm or a lack of number of sperm.
Testosterone replacement therapy nearly eliminates sperm production
~2 h 50 min
Exogenous testosterone — whether from TRT, patches, pellets, or injections — triggers negative feedback at the pituitary, suppressing LH and FSH release, which in turn eliminates the hormonal drive for spermatogenesis. The effect is drastic but partially reversible.
Why this matters: Many men on TRT are unaware that they are functionally chemically vasectomized. Because TRT is increasingly common, this is a critical fertility-planning point that is often missed until a couple has been trying unsuccessfully to conceive.
Background
Intratesticular testosterone is normally 100× higher than circulating testosterone — this local concentration is required for spermatogenesis. Exogenous testosterone saturates systemic receptors but suppresses the pituitary signal needed to maintain intratesticular levels.
Rescue strategies include hCG (which mimics LH to maintain intratesticular testosterone), exogenous FSH (to directly stimulate Sertoli cell support of spermatogenesis), clomiphene (to modulate the feedback axis), or complete cessation of TRT. Huberman emphasizes that supplement-based testosterone support — tongkat ali, zinc — does not suppress endogenous production and does not carry this risk; only taking a hormone from an external source triggers the feedback shutdown.
When men take exogenous, meaning from outside the body, testosterone... because of negative feedback loops, the testicles themselves shut down their own testosterone production... In other words, for men who are on TRT or who are taking testosterone from an external source, the number of sperm that they're going to make is going to be dramatically reduced.
Acupuncture has mechanistic NIH-funded evidence for improving both male and female fertility
~3 h 30 min
Clinical trials funded by the NIH now show that acupuncture can regulate FSH across the ovulatory cycle, improve blood flow to the ovary, increase semen volume and sperm motility in men, and elevate endogenous testosterone — through identified neural pathways, not placebo.
Why this matters: Acupuncture for fertility has historically been viewed as fringe. Harvard Medical School researcher Qiufu Fu's laboratory has now mapped the specific neural pathways (e.g., lower-limb stimulation sites reducing systemic inflammation via kidney/pancreas connections) that explain the effects mechanistically.
For women, acupuncture balances FSH to avoid premature ovulatory surges and supports endometrial blood flow. For men, the mechanism appears to improve vascular supply to the scrotum and testes — which is a temperature-regulation effect as well as a nutrient-delivery effect — and to stimulate Leydig cell testosterone production via neural pathways. Huberman cites a 2021 review paper: 'Acupuncture and Herbal Medicine for Female Fertility: An Overview of Systematic Reviews.'
There are a number of different excellent reviews on this, both as it relates to females and as it relates to males... acupuncture has been shown to improve semen volume, quality of sperm, sperm motility, et cetera, and in large part through changes in the neural pathways that innervate the very tissues and vascular input to the scrotum and testicles.
Fecundability drops dramatically with maternal age — 20% at 30, 5% at 38–39
~1 h 40 min
The per-cycle probability of a successful natural conception is approximately 20% for women aged 30 or younger, 18% at ages 31–33, 11% at ages 34–37, and roughly 5% at ages 38–39. By age 40 and older, it falls to 1–3%. These are the benchmarks clinicians use to decide when to recommend medical evaluation.
Why this matters: Most people grossly overestimate monthly conception rates; the actual probabilities mean a healthy couple under 30 should expect to try for at least 5–6 months before escalating to clinical evaluation, while women over 35 should consult an OB/GYN at the outset.
The mechanism of age-related decline is primarily mitochondrial dysfunction in aging oocytes, which impairs the spindle apparatus responsible for chromosomal segregation. Miscarriage rates reflect the same biology: 25% of successful fertilizations in women 35+ end in miscarriage, rising to ~50% in women 40+, mainly due to chromosomal abnormalities including trisomies. Huberman recommends AMH blood testing and antral follicle counts (ultrasound) starting in a woman's 20s as a baseline and repeated every few years.
For females 30 years old or younger, if they have intercourse with ejaculation around the time of ovulation... on average, that will result in a successful fertilization in pregnancy about 20% of the time on the first month of attempting.
Also said
“For women who are age 38 to 39, the probability of a successful conception by natural conception — intercourse with ejaculation — is going to be about 5%. So it's really dropped to a quarter of what it was when that woman was 30.”— Quantifies the steepness of the age-related decline from 30 to late 30s.
Recommendations
Products, supplements, and tools mentioned in the episode
Huberman recommends L-carnitine as the first-line supplement for improving both egg and sperm quality via mitochondrial lipid metabolism support. Garlic extract is co-required to offset TMAO elevation from oral L-carnitine.
1–3 grams L-carnitine per day, split or all at once, with or without food, for 30–60 days minimum. 600 mg garlic extract (allicin source) taken concurrently. The combination addresses two separate problems: L-carnitine supports mitochondrial function in eggs and sperm; garlic extract prevents the cardiovascular side effect of TMAO elevation.
1 to 3 grams per day of capsule form L-carnitine is what's been suggested to improve egg quality and sperm quality... if you are going to take oral L-carnitine, I suggest also taking 600 milligrams a day of garlic extract.
CoQ10 is Huberman's second core fertility supplement, prescribed by fertility specialists to support mitochondrial electron transport chain function in both oocytes and sperm.
100–400 mg/day, ideally taken with dinner or another fat-containing meal. Blood levels can be measured (target 0.5–2.5 on standard assay). Often prescribed by IVF clinics alongside L-carnitine.
The coenzyme Q10 dosages that are most often suggested and that you'll observe in the peer-reviewed research literature — on humans, I should add — is 100 to 400 milligrams per day.
Huberman recommends tongkat ali for both men and women as a supplement-based approach to reduce SHBG, increase free testosterone, and support libido and spermatogenesis without suppressing endogenous production.
400 mg once daily in the morning (mildly stimulating). No cycling required — effects on free testosterone and libido accumulate with consistent use. Distinct from TRT: tongkat ali does not suppress endogenous testosterone production.
Personal experience
Huberman has discussed tongkat ali as part of his own supplement stack in multiple episodes, citing its ability to reduce SHBG and increase free testosterone.
400 milligrams a day of tongkat ali has been shown to increase free testosterone by way of reducing something called sex hormone binding globulin... the increase in androgen created by tongkat ali supplementation can indeed lead to improved spermatogenesis.
Shilajit is a mineral pitch compound showing robust evidence for increasing testosterone and FSH in men, improving libido, sperm motility, and sperm count. Huberman cautions women to consult OB/GYN before use due to FSH-cycle timing concerns.
250 mg twice per day — available in capsule or as a tar resin dissolved in water. For women with regular cycles, chronically elevated FSH from Shilajit could disrupt the tight FSH oscillation across the menstrual cycle. For men, increasing FSH and testosterone together improves the Sertoli-Leydig cell axis that drives spermatogenesis.
vs alternatives
Tongkat ali and Shilajit both increase testosterone but by different mechanisms: tongkat ali primarily reduces SHBG; Shilajit appears to stimulate FSH and testosterone secretion directly. They are not interchangeable and can be combined.
Shilajit... at about 250 milligrams twice per day... does seem to significantly increase two hormones. One is testosterone, and the other is follicle-stimulating hormone.
Acupuncture from a licensed practitioner for fertility optimization
Practice
Supported by NIH-funded clinical trials and mechanistic research from Harvard Medical School (Qiufu Fu lab). Recommended as an adjunct to behavioral and supplemental protocols for both male and female fertility.
For women: acupuncture regulates FSH levels across the ovulatory cycle, improves ovarian blood flow, and supports endometrial receptivity. For men: stimulates neural pathways innervating the testes, improving scrotal vascular flow, Leydig cell testosterone production, and sperm motility. Reference paper: 'Acupuncture and Herbal Medicine for Female Fertility: An Overview of Systematic Reviews' (2021).
There are now quite a few clinical trials funded by government agencies, like the National Institutes of Health, showing that acupuncture is a very effective treatment for a number of different things, including fertility and pregnancy... acupuncture has been shown to improve semen volume, quality of sperm, sperm motility.
Snowball scrotal cooling underwear for male fertility
Tool
Commercially available gel-pack cooling briefs for lowering scrotal temperature in men trying to conceive. Mechanism is indirect: reducing heat that suppresses spermatogenesis, not direct stimulation.
Huberman acknowledges these exist under the brand name 'Snowballs.' Same principle applies to deliberate cold showers (1–3 minutes early in the day), which may also boost testosterone via dopamine/norepinephrine pathways as a secondary benefit.
You will find available online — I think they're actually called — forgive me, but that's what they're called — called snowballs. These are sort of like gel pack cold briefs that you can buy and men will wear for some period of time.
Lines worth pulling out — contrarian, specific, or perfectly phrased
6 items
The data indicate that sperm quality declines when people start using a mobile phone. So from the point they start using a mobile phone, regardless of the usage time — this is important — it used to be thought that it was four hours a day or more... It turns out that it's not related to usage time.
Overturns the prior four-hours-of-use threshold and establishes that any smartphone proximity to the groin reduces sperm quality.
One in five couples that have issues with fertility, the issue ends up falling on the biology that is the quality of the sperm or a lack of number of sperm.
Challenges the cultural assumption that fertility problems are predominantly a female biology issue — 20% of cases trace to sperm.
What is good for the woman is good for the egg and for fertility and for pregnancy. And what's good for the man is good for the quality and production of sperm and for fertility and pregnancy. Whether or not we are male or female, the things that we can do to optimize our fertility are the exact same things that we should all be doing to optimize our vitality and our longevity.
The thesis statement of the entire episode: fertility optimization is a proxy for longevity optimization, making the protocols universally relevant.
If you are a male and you have excessively big thighs, believe it or not, that it actually can lower sperm count substantially, whether or not the big thighs occur because you're very muscular or the big thighs occur because you are overweight. It can increase the temperature.
Unexpected finding that even high muscle mass in the legs can thermally compromise spermatogenesis — not just obesity.
For women who are age 38 to 39, the probability of a successful conception by natural conception — intercourse with ejaculation — is going to be about 5%. So it's really dropped to a quarter of what it was when that woman was 30.
The clearest single statistic on age-related fecundability decline, motivating early AMH testing and pre-conception planning.
The concentration of intratesticular testosterone is at least 100 times higher than the concentration of testosterone anywhere else in the body... when men take exogenous testosterone... the testicles themselves shut down their own testosterone production.
Explains mechanistically why TRT eliminates spermatogenesis — intratesticular testosterone concentration is the key variable, not systemic levels.
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Educational summary of the cited expert source — not medical advice. Open the source recording linked above and consult a qualified physician before acting on any protocol.
