Explore Dr. Retzler’s HormoneSynergy® Longevity Medicine Resource Library

Longevity Medicine, Functional Wellness & Anti-Aging Insights from HormoneSynergy®

Welcome to the HormoneSynergy® Longevity Medicine Blog, a physician-guided clinical library led by Dr. Kathryn Retzler. Our articles cover the systems that most often shape health with age: metabolic health, hormones, cardiovascular and kidney risk, body composition, bone and muscle, brain health, sleep, gut health, nutrition, supplements, and the biology of aging.

The library is organized around clinical questions rather than trends. Some articles review new research. Others explain testing, treatment, nutrition, or a condition patients commonly encounter. Across the collection, the standard is the same: evidence first, appropriate uncertainty, and enough clinical context to separate useful medicine from wellness marketing.

Start with the HormoneSynergy® Longevity Medicine Framework

New & recently updated:

Metabolic Health & Insulin Resistance

Clinical resources on insulin resistance, glucose regulation, metabolic syndrome, visceral fat, prediabetes, obesity and GLP-1-based care within a broader longevity medicine plan.

Kidney Health & Cardiovascular-Kidney-Metabolic Health

Kidney health belongs in the same clinical conversation as blood pressure, diabetes, insulin resistance, obesity and cardiovascular risk. These resources cover early detection, CKD, albuminuria, nutrition and CKM health.

Gut Health, Microbiome & Immune Signaling

Clinical education on the microbiome, intestinal barrier, fiber, inflammation, gut-brain signaling, immune biology and the growing connections between gut, metabolic and kidney health.

Food Quality, Vitamins, Supplements & Wellness Claims

Evidence-based guidance on nutrient gaps, supplement quality, interactions, food claims and longevity products, with an emphasis on where supplementation helps and where marketing outruns the evidence.

  • Type Three and Longevity: When Achievement Becomes Exhaustion

    Enneagram Type Three longevity image showing achievement, recovery, sustainable capacity, and health beyond performance in the HormoneSynergy approach.

    Type Threes often bring energy, drive, adaptability, and follow-through to health. They can execute a plan, track progress, and keep moving. But when achievement becomes the measure of worth, health can become another performance. In longevity work, the growth path for Type Three is learning that rest, honesty, and recovery are not obstacles to success. They are part of health.

  • HOMA-IR and Insulin Resistance: How to Interpret the Number

    HOMA-IR calculation showing fasting insulin and glucose with insulin resistance, visceral fat, triglycerides, ApoB, liver health, and muscle metabolism.

    HOMA-IR combines fasting glucose and fasting insulin to estimate insulin resistance. It can help identify metabolic dysfunction while glucose still looks normal, but the number has to be interpreted carefully. There is no universal HOMA-IR cutoff, and the result is most useful alongside fasting insulin, triglycerides, ApoB, visceral fat, liver health, and the rest of the metabolic picture.

  • Protein for Longevity: The Truth Between “Not Enough” and “Too Much”

    Protein for Longevity: How Much Do You Really Need

    Protein has become the loudest nutrient on the internet—praised as the key to fat loss, muscle, and longevity, and criticized as another overhyped trend. The truth is more nuanced. At HormoneSynergy® Clinic (Portland & Lake Oswego), we take a measured, evidence-based approach to protein that supports muscle, metabolism, and long-term health—without turning every meal into a performance.

  • Menopause and Andropause: Why Timing Matters for Long-Term Health

    Menopause and Andropause: Why Timing Matters for Long-Term Health

    Menopause and andropause are not endpoints—they are physiologic inflection points that shape bone, cardiovascular, metabolic, and cognitive health for decades. This article explains how hormonal transitions affect aging, why timing matters, and how early, thoughtful support preserves long-term resilience and independence.

  • The Enneagram and Longevity: How Self-Knowledge Shapes Health Change

    The Enneagram and Longevity: How Self-Knowledge Shapes Health Change
    Longevity is not only about labs, supplements, hormones, food, exercise, and sleep. It is also about the person who has to live the plan. The Enneagram can help reveal the patterns we bring to health change, stress, consistency, resistance, and growth.
  • When Health Becomes a Culture War

    When Health and Medicine enter the Social Media Culture War

    When health becomes a culture war, truth becomes optional — and the loudest voices win, not the most accurate ones. I’ve spent years alongside Dr. Kathryn Retzler watching real longevity medicine get distorted by influencer certainty, tribal outrage, and algorithm-driven “hot takes.” At HormoneSynergy® Clinic in Portland & Lake Oswego, we believe healthspan is built the unglamorous way: with a physician you trust, data you can measure, and follow-through you can sustain.

  • Chronic Inflammation and Healthy Aging

    Chronic inflammation clinical illustration showing elevated inflammatory activity affecting metabolism, brain function, and cardiovascular health

    Chronic inflammation is a persistent, low-grade immune response that can quietly affect metabolism, cardiovascular health, hormone balance, and aging. Over time, it may contribute to disease risk and reduced healthspan.

  • Sleep and Longevity: Why Restorative Sleep Belongs in Preventive Medicine

    Sleep and Longevity: Why Restorative Sleep Belongs in Preventive Medicine

    Sleep affects cardiovascular health, glucose regulation, appetite, hormone signaling, cognition, immune function and physical recovery. It is also where common but overlooked problems such as sleep apnea can quietly undermine otherwise thoughtful efforts to improve health. In longevity medicine, sleep deserves to be evaluated with the same seriousness as exercise, nutrition, body composition and cardiovascular risk.

  • Bredesen Protocol (ReCODE™) and the HormoneSynergy® Model: A Shared Precision Approach to Brain Health

    Bredesen Protocol (ReCODE™) and the HormoneSynergy® Model: A Shared Precision Approach to Brain Health

    We’ve followed Dr. Dale Bredesen’s work for years, attended multiple lectures, and appreciate how closely it aligns with the systems-based way we approach brain health. His ReCODE (Bredesen protocol) framework reinforces a key message: memory improvement and long-term cognitive performance are often supported by optimizing sleep, metabolism, inflammation, hormones, and nutrient status.

  • Visceral Fat and Metabolic Health: Why Where We Store Fat Matters

    Visceral fat clinical illustration showing abdominal fat around internal organs and metabolic health risk

    Visceral fat is more than an issue of body weight or appearance. Fat stored deep within the abdomen is closely associated with insulin resistance, fatty liver, dyslipidemia, inflammation, and cardiovascular risk. Understanding visceral fat—and following it alongside muscle mass, metabolic markers, and waist circumference—can provide a more meaningful picture of metabolic health than weight or BMI alone.

  • Metabolic Health Matters More Than Weight for Long-Term Longevity

    Functional Medicine and Metabolic Health Oregon

    Weight alone does not define health. Many people develop insulin resistance, muscle loss, and metabolic dysfunction years before diabetes or obesity appear. This article explains why metabolic health—not the scale—is foundational to longevity, and how strength, sleep, and early intervention protect long-term healthspan.

  • Vitamin D3 and Longevity: What It Does, What the Evidence Shows

    Vitamin D3 and Longevity: What It Does, What the Evidence Shows

    Vitamin D matters for bone, muscle and normal physiology, but longevity medicine should distinguish established biology from claims that higher levels or larger supplements necessarily improve long-term health.