Happy Thursday, Zapien — Here’s what we’re diving into in this week’s issue:
Testosterone Therapy and Fertility: You Don’t Have to Choose – The outdated either/or framing around TRT and fertility is dead. New tools like enclomiphene and short-acting testosterone formulations let men raise their levels without shutting down sperm production. Here’s the full spectrum of options—and the 5 lab markers to track.
Safe Supplement Guide — With hundreds of options on the market, even experienced optimizers second-guess their stack. This guide cuts through the noise and ranks the 10 with the strongest safety and efficacy profiles.
Community highlights: Blood glucose behavior during high-intensity training, the evidence behind black cumin oil and spirulina for allergies, and practical protocols for reducing nighttime wake-ups.
Dr. Kyle Gillett’s Health Stack – Dual board-certified physician in family medicine and obesity medicine, expert on testosterone optimisation, and one of Andrew’s Huberman most featured guests. His approach centers on the “7 pillars of health”: exercise, diet, sleep, stress, social, sunlight, and spirit.
Forever,
Karol, Martin, Simon & Andy
Community Discussion
Testosterone Therapy and Fertility: You Don’t Need to Choose
Many men assume testosterone therapy means giving up fertility. That’s no longer true. Untreated low testosterone goes beyond fatigue — it drives visceral fat gain, insulin resistance, cognitive decline, and bone density loss over time.
A large-scale clinical trial involving over 5,000 men also confirmed that testosterone therapy doesn’t increase cardiovascular risk, which was a long-standing concern. Today, options like enclomiphene and short-acting oral or topical testosterone let men raise their levels while keeping sperm production intact.
The article breaks down the full spectrum of protocols, explains how each one balances testosterone elevation with fertility preservation, and identifies the five lab markers that keep everything dialed in.
Short Hack Long Life
The Vitamin D–Testosterone Connection
A 2011 randomized controlled trial found that those who supplemented with ~3,300 IU of vitamin D3 daily for 12 months saw total testosterone rise by 25% and free testosterone increase significantly. The placebo group saw no change. The effect was strongest in men who were deficient at baseline — below 50 nmol/L. A larger cross-sectional study of 1,362 men from Harvard confirmed the association: testosterone levels climbed linearly with vitamin D up to about 75–85 nmol/L, then plateaued.
The fix: Most men in Europe are vitamin D deficient between October and May. That’s half the year where your testosterone may be running lower than it needs to for no reason other than a cheap, correctable nutrient gap. Vitamin D is fat-soluble, acts more like a hormone than a vitamin, and is required for Leydig cell function — the cells in your testes that actually produce testosterone. Correcting a deficiency is one of the simplest interventions with downstream effects on testosterone, bone density, immune function, and mood.
The Protocol:
🕐 When: Daily, with your largest meal containing fat. This increases absorption by up to 50%. Morning or lunch preferred.
🎯 Dose: Get your 25(OH)D levels tested. Below 50 nmol/L — take 3,000–4,000 IU of D3 daily. Between 50–75 nmol/L — 2,000 IU to maintain. Target range: 75–100 nmol/L.
🚫 Common mistakes: Taking D2 instead of D3 (less bioavailable). Supplementing without retesting. Ignoring magnesium — it’s required for vitamin D metabolism. If your magnesium is low, your D3 won’t convert properly.
📊 Tracking: Retest 25(OH)D after 3 months. If testosterone is a concern, add total testosterone and SHBG to the same draw. Compare trends across two panels minimum — single snapshots are unreliable.
Safe Supplement Guide
Top 10 Safe Supplements That Belong In Every Stack
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WhatsApp Group Summary
Blood Glucose Spikes During VO2max Training
Discussion: A member wearing a CGM noticed blood glucose spiking to 160–170 during Nordic 4x4 interval training — significantly higher than any previous cardio sessions. She asked whether this was normal.
The verdict: The community pointed to cortisol as the likely driver. High-intensity protocols like 4x4 intervals push the sympathetic nervous system harder than steady-state cardio, triggering a liver glucose dump to fuel the effort. Several members noted that the spike may not be caused by the exercise alone — stress load, sleep, timing of meals, and overall recovery status all influence how aggressively cortisol responds during a session.
Consider this: Seeing glucose rise during intense exercise isn’t a sign something is broken. It’s your body mobilizing fuel for high output. The number that matters more is how quickly glucose returns to baseline after the session. If it normalizes within 60–90 minutes, the system is working as designed. Persistent elevation post-workout is where it’s worth digging deeper — into recovery, sleep quality, or cumulative stress load.
Black Cumin Oil for Allergies — Does It Work?
Discussion: A member asked whether black cumin oil has any real evidence behind it for pollen allergies, after his wife heard it could help.
The verdict: The community dug into the research. Examine.com lists three studies on black seed (Nigella sativa) and rates it as “high potential” for allergy-related symptoms — showing benefits across rhinitis, eczema, and asthma. A Consensus.app search backed this up with additional supporting literature. One member also flagged spirulina as a strong alternative, pointing to a 2020 review showing benefits for allergic rhinitis symptoms.
Consider this: The evidence for black seed oil in allergies is more robust than most people expect — it’s not just folk medicine. The active compound thymoquinone has demonstrated anti-inflammatory and antihistamine-like effects in clinical settings.
Reducing Nighttime Bathroom Visits
Discussion: A member asked whether anyone has found a nighttime protocol that reduces wake-ups for bathroom visits — noting that full diagnostics showed no underlying medical issue
The verdict: One member shared a 10-second pre-bed protocol from ANF Therapy that they found helpful for improving sleep continuity. The approach focuses on frequency-based wearable patches designed to support autonomic nervous system regulation during sleep.
Consider this: Nocturia without an underlying diagnosis often comes down to fluid timing, sodium balance, and bladder signaling. Cutting liquids 2–3 hours before bed is the obvious move, but less discussed: evening electrolyte balance plays a role. Too little sodium earlier in the day can cause your body to retain and redistribute fluid at night. For a deeper dive into building a complete sleep protocol, check out our Deep Sleep Guide — it covers the full stack from environment to supplementation.
Community Health Stack
Dr. Kyle Gillett
Kyle is a dual board-certified physician (family medicine + obesity medicine), world famous expert on testosterone optimization, host of The Gillett Health Podcast, and one of Andrew Huberman’s most-featured guests.
Kyle`s Health Routine
MORNING ROUTINE
He wakes up around 4-5 AM and goes to the gym. His typical workout includes a combination of CrossFit, strength training, and track workouts.
EXERCISE
His personal training approach mirrors what he recommends clinically: vigorous exercise 3-4x per week, with less vigorous exercise on other days. He advises keeping intense training sessions under one hour for hormonal health. His mix includes CrossFit-style functional fitness, heavy strength training, track/sprint work, and zone 2 cardio. He’s emphasized that zone 2 cardio is particularly good for mitochondrial health, along with REM sleep — and that these two things benefit mitochondria more than any supplement stack.
DIET
He’s an omnivore who strongly advocates against pure carnivore or pure vegan diets, especially for younger men, as they can reduce free androgens. His dietary approach is farm-to-table: some of the most rewarding meals he has come mostly or entirely from his home garden and farm. He keeps chickens and considers eggs one of his favorite foods. He prioritizes high-quality protein sources, high-fiber foods, and whole fruits. He personally identified about half a dozen foods he loves that are nutrient-dense and eats those before anything else.
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Health Disclaimer
New Zapiens’ products and services are not intended to substitute for professional medical guidance. Our content and media offerings do not aim to diagnose, cure, or address any medical issues.
