The 4-Hour Body: Improving Sex and Doubling Sperm Count
These two chapters are about male hormones and fertility. Tim opens chapter 21 with a story about a date where he was practically radiating pheromones after weeks of testosterone experiments. His date, a CEO, was climbing over him at the restaurant before bread arrived. Women across the room couldn’t stop staring. His scratches from the night healed like Wolverine.
Cool story, Tim. But what actually happened under the hood?
The Testosterone Problem
Between ages 30 and 32, Tim noticed something off. He could still perform fine in bed, but he wanted to less and less. Sex frequency kept dropping. Once a day became a few times a week, then once a week. He felt healthy otherwise. Gym numbers were fine. Energy was fine.
Blood tests told a different story. His total testosterone came back at 244.8 ng/dL - technically in the “normal” range, but barely. Low end. At 31 years old.
Here’s the thing most people don’t know. Testosterone production is a chain reaction. Your hypothalamus tells your pituitary gland to release luteinizing hormone (LH). LH then tells your testicles to make testosterone. If any link in that chain breaks, your numbers drop.
The common medical response is to prescribe testosterone gel or injections. Ferriss calls this a mistake if you haven’t checked what’s broken upstream first. Throwing external testosterone at the problem can actually make your body stop producing its own. Bad idea for the long term.
He also found something interesting. When he experimented with hCG (a hormone that mimics LH), his sex drive went through the roof. Three to four times a day kind of drive. But straight testosterone injections - which doubled his T levels - did nothing for libido. The takeaway: luteinizing hormone matters more for sex drive than raw testosterone numbers.
Protocol 1: The Long-Term Fix
This is the daily maintenance approach. Four things:
Fermented cod liver oil + vitamin-rich butter fat - 2 capsules when you wake up, 2 before bed. Tim used a specific brand called Blue Ice that combines both. Kerrygold Irish butter works as a substitute for the butter fat part.
Vitamin D3 - 3,000 to 5,000 IU when you wake up AND before bed. That’s 6,000 to 10,000 IU per day total. But don’t just guess your dose. Get your blood levels tested first and aim for 55 ng/mL. Overdosing on vitamin D has real side effects.
Cold showers or ice baths - 10 minutes each, morning and night.
Brazil nuts - 3 nuts in the morning, 3 at night. These are a selenium source. Tim was deficient in selenium, which he discovered through specialized blood testing. He doesn’t recommend Brazil nuts unless you’re actually deficient.
Protocol 2: The Short-Term Boost
This is the “big night coming up” protocol.
20-24 hours before: Eat at least 800 milligrams of cholesterol. Four or more whole eggs before bed, or a couple of big rib-eye steaks. Testosterone is made from cholesterol, and your body produces most of it between midnight and 6 AM. Give it raw materials.
4 hours before: Eat 4 Brazil nuts, 20 raw almonds, and 2 capsules of the fermented cod liver oil blend.
Why cholesterol? There’s a protein called SHBG (sex-hormone binding globulin) that grabs onto testosterone and makes it useless. More cholesterol in your diet means less SHBG. Less SHBG means more free testosterone your body can actually use.
Tim cites research showing that strict low-cholesterol diets lower testosterone by 14%. Vegetarian diets with low protein can push SHBG even higher, further reducing usable testosterone. High-protein, low-carb diets do the opposite.
The Results
Using Protocol 1 (without Brazil nuts at first), Tim’s numbers over about five months:
- Total testosterone: 244.8 to 653.3 ng/dL
- Bioavailable testosterone: 150 to 294
- Estradiol (estrogen): 39 down to under 20
When he added Brazil nuts later, total testosterone climbed to 835 - more than triple his starting point.
And here’s the part that surprises people. After eating grass-fed beef three times daily for 21 days straight in Nicaragua, his cholesterol actually improved. Total cholesterol went from 200 to 190. LDL dropped from 133 to 108. His cholesterol-to-HDL ratio got better. All without any drugs. His kidney markers barely moved.
Chapter 22: The Sperm Count Crisis
Now the fertility chapter. Tim opens with a researcher named Louis Guillette telling a congressional committee: “Each man in this room is half the man his grandfather was.” Not a metaphor. Sperm counts in industrialized countries have been falling roughly 1% per year since 1942. In Denmark, over 40% of men had already dropped below the sub-fertility threshold.
Tim went to a sperm bank in 2008. Not because he was worried - he just wanted insurance. He was 31, athletic, ate clean. No reason to worry, right?
His results came back borderline low. He retested. Even lower. Over the next 12 months, every test showed declining numbers.
He tried removing environmental pollutants from his body. Barely moved the needle. He called top urologists. One told him: “Male fertility is a relatively infertile field. There is so little one can do.”
The Cell Phone Discovery
Then came the turning point. While preparing to interview strength coach Charles Poliquin, Tim learned that Poliquin refused to carry a cell phone due to radiation’s correlation with low testosterone in athletes.
Tim hit the research databases. Over 70% of studies he found - mostly European - concluded cell phone radiation impairs sperm function. One study divided 361 men into groups by daily phone use: no use, under 2 hours, 2-4 hours, and over 4 hours. Every sperm parameter got worse as phone use went up. Another study exposed rats to cell phone radiation for just one hour daily over 28 days and found significantly reduced motile sperm.
Tim had been carrying his phone in his front pocket 12 hours a day for 10 years.
The Fix
Simple rule: phone stays away from testicles. He used a sports armband on his upper arm. When that wasn’t practical, he turned the phone off before pocketing it and checked messages every 30 minutes. A backpack pocket works too.
He waited 11 weeks to retest - sperm production takes about 64 days, so he wanted a full cycle plus buffer time.
Results after 11 weeks:
- Ejaculate volume: up 44%
- Motile sperm per milliliter: up 100%
- Motile sperm per ejaculate: up 185%
Nearly tripled his motile sperm count. He admits he also started cold treatments and Brazil nuts during the same period, so he can’t isolate which change did what. But he also says he doesn’t care about academic purity. He cared about results, and the results were clear.
The Practical Takeaways
From both chapters, here’s what stacks up:
- Get your testosterone and sperm tested before assuming everything is fine
- Fermented cod liver oil, vitamin D3, and Brazil nuts (if selenium-deficient) are the daily foundation
- Cholesterol before bed boosts next-day testosterone production
- Keep your cell phone away from your pockets
- Cold exposure helps both testosterone and sperm quality
- Don’t jump to testosterone replacement without checking the full hormone chain first
Tim also makes a practical case for sperm banking even if you’re healthy. About $1,000-1,200 for six deposits plus $300-600 per year for storage. Cheap insurance when you consider that accidents happen, medical treatments can cause infertility, and people who swear they don’t want kids often change their minds later.
These chapters are blunt and personal. Tim talks about his own declining numbers, his fear, and the specific steps he took. No magic pills. Just supplements, lifestyle changes, and keeping your phone out of your pants.
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This is part of my 4-Hour Body retelling series. New posts every Saturday.