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.

  • Subtypes and Self-Care: Self-Preservation, Social, and One-to-One Patterns

    Enneagram subtypes image showing Self-Preservation, Social, and One-to-One patterns in self-care, health behavior change, and sustainable longevity in the HormoneSynergy approach.

    The Enneagram subtypes add another layer to health change. They help us notice where our attention goes first: survival and comfort, belonging and role, or intensity and connection. In longevity work, these instinctual patterns can shape how we approach food, sleep, stress, relationships, boundaries, recovery, and follow-through.

  • Unplugging to Reconnect: Why Stepping Away Might Be the Missing Piece in Longevity

    Unplugging to reconnect in nature walking trail at sunset improving mental health and longevity HormoneSynergy Longevity Medicine

    In a world of constant noise, distraction, and digital overwhelm, unplugging may be one of the most overlooked tools for improving health, clarity, and longevity.

  • Thyroid Function, Metabolism, and Longevity Medicine: TSH, Free T4, Free T3, Optimal Ranges, and Treatment Options

    Thyroid function, TSH, Free T4, Free T3, optimal ranges, and thyroid treatment options reviewed through a clinical longevity medicine lens at HormoneSynergy®.

    Thyroid function is more than a TSH number. TSH, Free T4, and Free T3 help reveal how the thyroid is signaling, producing, converting, and delivering hormone activity to the body. In longevity medicine, thyroid interpretation should include symptoms, metabolic health, cardiovascular risk, bone health, thyroid antibodies, medication history, and individualized treatment decisions.

  • BMI Isn’t Enough — But Body Composition Still Matters

    BMI Isn’t Enough — But Body Composition Still Matters

    BMI has limitations — and modern medicine is evolving beyond it. But replacing BMI with the idea that body composition doesn’t matter risks misunderstanding the real drivers of metabolic health, longevity, and disease risk.

  • Estradiol in Men and Women

    Estradiol clinical illustration showing hormone effects on bone, metabolism, and overall balance in both men and women

    Estradiol is often thought of as a female hormone, but it plays an important role in both men and women. It influences bone health, body composition, brain function, cardiovascular health, and overall hormone balance.

  • Statins, Dementia & Side Effects: Separating Evidence From Influencer Myths (Portland • Lake Oswego • USA)

    Statins, Dementia & Side Effects: Separating Evidence From Influencer Myths (Portland • Lake Oswego • USA)

    Are statins linked to dementia? What is the true incidence of statin side effects? At HormoneSynergy® Clinic in Portland and Lake Oswego, we separate medical evidence from influencer myths and explain what large clinical trials actually show about statin safety and cardiovascular risk reduction.

  • Testosterone in Men and Women

    Testosterone clinical illustration showing hormone effects on muscle mass, metabolism, and energy in both men and women

    Testosterone is often thought of as a male hormone, but it plays an important role in both men and women. It influences muscle mass, energy, metabolism, mood, and long-term health.

  • Type One and Longevity: From Perfectionism to Sustainable Discipline

    type-one-enneagram-longevity-perfectionism-sustainable-discipline-hormonesynergy.jpg

    Type Ones often bring discipline, integrity, and a sincere desire to do things well to their health. But when perfection becomes the standard, consistency can become harder. In longevity work, the growth path for Type One is learning how to build strong foundations without turning health into another moral scorecard.

  • Are Supplements on Amazon Authentic? A Physician-Led Perspective

    Are Supplements on Amazon Authentic? A Physician-Led Perspective

    HormoneSynergy® is transitioning away from Amazon to uphold the integrity of our supplements, ensure verified inventory control, and maintain transparent chain-of-custody. As a clinician-led preventive longevity clinic based in Portland and Lake Oswego, Oregon, we are committed to direct distribution, reflecting our own integrity as a business. This allows us to continue offering personalized care and maintaining the high standards we stand behind, while still shipping nationwide across the USA.

  • Binge Drinking, “Leaky Gut,” and the Microbiome: What Human Studies Actually Show (Portland • Lake Oswego • USA)

    Binge Drinking, “Leaky Gut,” and the Microbiome: What Human Studies Actually Show (Portland • Lake Oswego • USA)

    Human clinical data shows alcohol—especially binge drinking—can increase gut permeability (“leaky gut”), raise endotoxin (LPS) in the bloodstream, and trigger immune activation. Here’s what’s causation vs association, what shifts in the microbiome are most consistent in heavy drinkers, and practical Harm-Reduction steps (nutrition, exercise, metabolic health, and targeted support like NAC/glutathione) if you choose to drink.

  • Preventive Cardiology Protocol (Dr. Retzler) | HormoneSynergy® Clinic

    Preventive Cardiology Protocol (Dr. Retzler) | HormoneSynergy® Clinic

    HormoneSynergy® Clinic’s HS STACK™ Preventive Cardiology Protocol is Dr. Retzler’s measurement-driven approach to cardiovascular longevity—built around ApoB particle burden, Lp(a), insulin resistance, inflammation, body composition (DEXA/SECA), and longitudinal tracking. Serving Portland & Lake Oswego, Oregon, with nationwide education and USA supplement shipping.

  • MaxSimil® Fish Oil: High-Absorption Omega-3 for EPA/DHA Support (Portland, Lake Oswego & USA Shipping)

    RetzlerRx Pure Omega 1300 EC professional-grade omega-3 fish oil in Portland Oregon with nationwide USA shipping

    MaxSimil® Fish Oil is our go-to omega-3 for advanced EPA/DHA absorption—ideal for heart, brain, inflammation balance, and cardiometabolic longevity. Compare MaxSimil® to our Omega 650 EC option and choose the right professional-grade fish oil for Portland & Lake Oswego, Oregon, or anywhere in the USA.