Hormones
Male hormone optimization
Total and free testosterone, SHBG, estradiol, prolactin, LH/FSH, cortisol and thyroid. How they read together and what changes when they're corrected.
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Doctor PN · Men's health
Understand your biology before your biology understands you.
Straight medical education on hormones, fertility, sexual health, prostate and longevity. By Paulo Navarrete, Urology specialist licensed in Venezuela. Educational content only, not medical care.
Medical education
Urology · Andrology
Six domains
Everything a man
Everything a man
should be able to ask.
The topics that generate the most silence in consultation, explained at the same level of detail I'd give a patient — in an open, free format.
Fertility
Male fertility
The semen analysis step by step, motility, morphology, DNA fragmentation and varicocele. Half of infertility cases involve a male factor.
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Sexual health
Sexual function and desire
Erectile dysfunction of vascular, hormonal or psychogenic origin; premature ejaculation; low desire. Find the cause before medicating.
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Prostate
Prostate and metabolism
Enlargement, PSA explained without alarm, screening by age and risk, and the link between prostate, weight and insulin.
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Longevity
Male longevity
Sleep, strength, VO₂ max, body composition and supplementation that holds up. What moves the needle and what just sells.
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Prevention
Prevention and STIs
HPV, HIV, syphilis, PrEP and routine screening. Direct clinical information, no judgment, no detours.
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How I handle the information
Evidence first.
Evidence first.
Opinion last, and labeled.
Not everything circulating about men's health carries the same weight. So I separate clearly what is clinical consensus, what is emerging evidence, and what is personal judgment.
- Consensus: current urology and andrology society guidelines.
- Emerging evidence: recent studies, with sample size and limitations stated.
- Clinical judgment: what I observe in practice, flagged as such and never presented as a rule.
- What I don't do: promise outcomes, sell miracle supplements or diagnose over the internet.
Frequently asked
What every man wants to know.
When should I check my hormones for the first time?+
As a general reference, it makes sense to have a baseline panel from age 30 — earlier if there are symptoms: persistent fatigue, low desire, loss of muscle mass, mood changes or difficulty conceiving. A useful panel isn't total testosterone alone: it includes free testosterone, SHBG, estradiol, prolactin and LH/FSH, drawn fasting in the morning. Interpretation always belongs to your treating physician.
Do you recommend testosterone replacement therapy?+
It's a serious clinical tool, not a lifestyle shortcut. It comes up when there is confirmed hypogonadism — low values on two morning draws plus consistent symptoms — and after sleep, body composition, training, alcohol and stress have been addressed. It also means a conversation about fertility, hematocrit and long-term monitoring. None of that gets decided by reading a web page.
Does this site offer consultations or treatment?+
No. Doctor PN is an educational platform. Nothing here is a diagnosis or a prescription, and no doctor–patient relationship is created. The goal is for you to walk into your own licensed physician's office better informed — not to replace that visit.
Why so much emphasis on male fertility?+
Because it's still the blind spot in the process. A male factor is involved in a large share of couples struggling to conceive, and yet the man is usually evaluated last. A properly done semen analysis is simple, inexpensive, and it changes the direction of everything that follows.
How is your approach different from a traditional urologist's?+
Classical urology steps in once there is pathology. The educational work starts earlier: hormones, fertility, sexual function, metabolism and longevity treated as one system rather than separate appointments. It's still urology — with a wider read on the whole man.
MEDICAL DISCLAIMER · The content in this section is educational and for general
information. It does not replace evaluation by a health professional, does not constitute diagnosis
or prescription, and does not create a doctor–patient relationship. If you have symptoms or questions
about your health, consult a physician licensed in your jurisdiction. In an emergency, go to your
nearest emergency department.
Learn first.
Decide after.
Every week I send one email with what I'm reading, applying and discarding in men's health. No promises, no hard selling.