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
- The HormoneSynergy® Philosophy
- Medicine, Not Marketing
- What Actually Moves Longevity Metrics
- HormoneSynergy® Longevity Medicine Resource Center
- The HormoneSynergy® Longevity Medicine Model
- The Ultimate Longevity Medicine Guide
- Concierge Longevity Medicine in Portland & Lake Oswego
- Is HormoneSynergy® the Right Fit for You?
Browse by clinical area:
New & recently updated:
- Chronic Kidney Disease Is Common, Quiet, and Often Missed
- The Adult Thymus May Matter More Than We Thought
- Do I Need a Multivitamin? What the Evidence Actually Shows
- The Grass-Fed Tallow Halo: Better Beef Fat Is Still Beef Fat
- The Metabolic Health Crisis Is Not a Supplement Deficiency
- A Tick Bite Can Cause an Infection. It Can Also Cause an Allergy.
- Does Estrogen Protect the Brain? What the New 2026 Research Shows
- Protein After 50: How Much Do You Need to Preserve Muscle?
- Supplements on GLP-1 Medications: Protein, Fiber, Muscle and Nutrient Intake
- Supplements for Menopause: What May Help, What’s Overhyped and What to Measure
- Vitamin D: Who Should Take It, Who Should Test, and How Much Is Too Much?
- Can You Take Too Many Vitamins? The Hidden Problem of Supplement Stacking
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.
- Metabolic Health and Insulin Resistance Guide
- HOMA-IR Explained
- Fasting Insulin and Metabolic Health
- Metabolic Syndrome
- Continuous Glucose Monitoring
- Prediabetes Remission and Metabolic Health
- The Metabolic Health Crisis Is Not a Supplement Deficiency
- Nutrition and Supplements on GLP-1 Medications
- GLP-1 Therapy Within Concierge Longevity Medicine
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.
Body Composition, Bone & Muscle Longevity
Resources on DEXA, SECA, visceral fat, lean mass, sarcopenia, bone density, exercise and preservation of physical reserve with age.
Hormones, Menopause & Healthy Aging
Physician-guided resources on menopause, hormone therapy, testosterone, thyroid physiology, DHEA, body composition, bone health and the clinical transitions that accompany aging.
- Hormone Transitions and Longevity Medicine
- Hormone Optimization and Longevity Medicine
- Bioidentical Hormone Therapy for Women and Men
- Hormone Therapy for Women
- Testosterone Therapy for Men
- Estrogen, Menopause and the 2026 Dementia Research
- Supplements for Menopause: What May Help and What to Measure
- Thyroid Function and Metabolic Health
- DHEA for Longevity
Preventive Cardiology
Early cardiovascular risk assessment, vascular imaging, ApoB, Lp(a), blood pressure, plaque, inflammation and the overlap between heart, kidney and metabolic health.
- Preventive Cardiology and Longevity Medicine
- Cleerly® Coronary CT Angiography with AI Plaque Analysis
- Carotid Artery Ultrasound / VasoLabs
- CKM Syndrome: Heart, Kidney and Metabolic Health
- Hypertension and Longevity
- ApoB and Longevity
- Lipoprotein(a) and Genetic Cardiovascular Risk
- High LDL, Low Triglycerides: Does ApoB Still Matter?
- Statins and Muscle Loss
Brain Health & Cognitive Longevity
Resources connecting cognition with vascular health, insulin resistance, menopause, sleep, inflammation, muscle, exercise and neurocognitive testing.
- Brain Longevity and Cognitive Health
- CNS Vital Signs Neurocognitive Testing
- Fasting Insulin and Brain Health
- Estrogen, Menopause and Dementia Research
- Obstructive Sleep Apnea, Brain Health and Longevity
- Sarcopenic Obesity and the Brain
- Omega-3s and Brain Health
- Vagus Nerve Stimulation: Science, Evidence and Hype
Sleep, Recovery & Energy
Sleep quality, obstructive sleep apnea, recovery capacity, caffeine, fatigue and the cardiovascular, metabolic and cognitive effects of inadequate sleep.
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.
- Gut Microbiome Health Guide
- Gut Health, Microbiome and Longevity Medicine
- Fiber, the Gut Microbiome and Longevity Medicine
- Prebiotics, Fiber and Synbiotics for Longevity
- LPS, Endotoxemia and Longevity
- Bifidobacterium and Longevity
- GLP-1 Signaling, the Microbiome and Hormones
- The Adult Thymus and Immune Aging
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.
- What Vitamins Should I Take? Evidence-Based Guide
- HormoneSynergy® Supplement Guide & Clinical Catalog
- Do I Need a Multivitamin?
- Vitamin D: Testing, Dosing and How Much Is Too Much?
- Can You Take Too Many Vitamins?
- Supplements and Prescription Medication Interactions
- Are Supplements Regulated?
- The Practical Longevity Supplement Stack
- The Grass-Fed Tallow Halo
- The $16,000 Longevity Stack
Additional Clinical Topics
Broader clinical subjects that affect healthspan, function or medical decision-making and connect back to the HormoneSynergy® longevity framework.
- The Adult Thymus, Immune Aging and Longevity
- Hair Loss in Men and Women
- Mental Health and Longevity
- Tick Bites, Lyme Disease and Alpha-Gal Syndrome
- Arthritis, Hormones, Inflammation and Joint Health
- Cancer Risk Is Not Just Bad Luck
- Alcohol, Obesity and Cancer Risk
- Centenarians, Mitochondria and the Myth of Genetic Luck
