What CGM numbers actually predict long-term health, and what is still unproven. Evidence-based context for time-in-range, mean glucose, glycemic variability, and fasting glucose in non-diabetic adults using CGM for longevity purposes.
How to read and act on coronary CT angiogram results at every age, from your 30s through your 70s and beyond. Covers normal ranges, plaque burden scoring, and evidence-based treatment thresholds.
What do your coronary CT angiogram results mean for longevity? Learn the optimal CCTA target ranges, plaque categories, and clinical thresholds used in preventive cardiology and longevity medicine.
How sex hormones and the menstrual cycle affect DEXA body composition results, what normal and optimal ranges look like for men and women, and why these differences matter for GLP-1 lean mass tracking.
A specific look at DEXA T-scores and Z-scores, the WHO osteoporosis classification, longevity-medicine target ranges above the diagnostic floor, and how FRAX and T-score together shape treatment decisions.
Fasting isn't required before a DEXA scan. Learn what actually affects results, like calcium timing, weight swings, and metal on the scan field.
Learn how to interpret DEXA bone density rate-of-change scores, understand T-scores and Z-scores, identify when alendronate or other interventions are warranted, and see what longevity-medicine guidelines say about optimal bone mineral density targets.
A clinical guide to how medications, hormones, and supplements shift DHEA-S levels, what the optimal range looks like by age and sex, and how to interpret results in the context of HRT, corticosteroids, and GLP-1 therapy.
Learn exactly how nutrition, fasting, caffeine, supplements, and meal timing affect DUTCH test results, including cortisol, estrogen metabolites, androgens, and organic acids. guidance with primary-source citations.
Learn how diet, protein intake, fasting, and hydration shift eGFR readings, what the optimal eGFR range is, and how clinicians interpret results before prescribing GLP-1s, metformin, or TRT.
How aerobic training, resistance exercise, and high-intensity intervals affect eGFR values, what the optimal eGFR range looks like, and how to interpret post-exercise dips before dosing GLP-1s, metformin, or TRT.
What is the optimal epigenetic age (DNAm) range? A clinically sourced guide to GrimAge, Horvath, and DunedinPACE targets, interpretation, and interventions backed by primary literature.
A decade-by-decade guide to interpreting erythrocyte sedimentation rate (ESR), covering how reference ranges shift with age and sex, the Westergren formula and its limits, and when an ESR result should prompt urgent evaluation rather than a routine repeat.
The age-adjusted ESR upper limit formula (age+10)/2 for women is discussed alongside how to track ESR trends over time, not just single values against fixed ranges.
A complete guide to estradiol (sensitive) at-home testing, finger-prick options, normal ranges, and optimal targets for men on TRT, women on HRT, and perimenopausal individuals.
Estrone (E1) normal ranges, optimal longevity-medicine targets, and clinical interpretation for postmenopausal women and aging men, with primary-source citations.
Understand fasting triglyceride results, medicines that raise or lower them, cardiovascular trial findings and the follow-up questions that guide treatment.
Why ferritin reference ranges differ by sex, how menstrual cycles and hormones shift iron stores, and what optimal ferritin actually means for hair loss, restless legs, thyroid function, and longevity.
How diet, fasting, inflammation, and lifestyle choices raise or lower ferritin, and what the optimal range looks like for iron stores, hair loss, restless legs, and longevity medicine.
Evidence-based optimal ranges for serum folate and RBC folate in longevity medicine, covering MTHFR, methylation, cardiovascular risk, and cognitive health with primary-source citations throughout.
A guide to Free T3 normal ranges, longevity-medicine target ranges, how Free T3 differs from TSH and Free T4, and when optimization matters for long-term health.
Evidence-based guide to Free T4 normal ranges, longevity-medicine targets, and clinical interpretation. Includes primary literature citations, society guidelines, and a decision framework.
Board-reviewed guide to free testosterone reference ranges, longevity-medicine targets, testing methods, and dose-titration benchmarks for TRT and HRT. Includes primary-literature citations and clinical decision framework.
Chronic resistance training raises resting free testosterone modestly, up to 15-20%, driven by lower body fat and better sleep, not training alone.
A guide to galectin-3 normal ranges, optimal longevity targets, cardiac fibrosis risk, and how to interpret your result in the context of heart failure prognosis and biological aging.
How diet, fasting and supplements affect urinary organic acids, with Genova collection guidance, vitamin-marker interpretation and practical follow-up.
Learn how GGT levels change by age decade, what the optimal GGT range is, and how to interpret your result in the context of liver health, alcohol intake, and oxidative stress.
What are optimal GIP (gastric inhibitory polypeptide) levels for longevity medicine? Understand normal ranges, tirzepatide mechanisms, and clinical target thresholds backed by primary literature.
GlycoMark (1,5-AG) drops sharply with SGLT-2 inhibitors and can fall after GLP-1 agonists. Learn which drugs alter 1,5-anhydroglucitol, how to interpret results during treatment, and what the optimal range looks like for metabolic health.
Learn how diet, fasting, carbohydrate intake, and postprandial glucose spikes alter GlycoMark (1,5-AG) levels, what the optimal range is, and how to interpret your result in clinical context.
Learn how testosterone, EPO, GLP-1 agonists, and other medications raise or lower hematocrit, what the optimal range is, and when your clinician should act. Evidence-based.
A complete clinical guide to IGF-1 at-home and finger-prick testing, including normal ranges, optimal IGF-1 levels for longevity and GH peptide therapy, collection methods, and how to interpret results.
Resistance training, aerobic exercise, and periodization all shift IGF-1 concentrations in measurable ways. Learn what the research says about optimal IGF-1 ranges, how to interpret your lab results, and when to consider clinical intervention.
A guide to IGFBP-3 normal ranges, longevity-medicine target ranges, and how this GH-axis biomarker pairs with IGF-1 to guide peptide, GH, and anti-aging protocols.
A decade-by-decade guide to interpreting serum iron, TIBC, and transferrin saturation, covering normal ranges, iron deficiency, and hemochromatosis risk from childhood through older adulthood, with a framework for what to test next.
A guide to reading your salivary melatonin profile by age decade, including normal ranges, optimal targets, and actionable steps when results fall outside reference values.
Learn how aerobic exercise, resistance training, timing, and training load all shift the salivary melatonin profile, what the normal range looks like, and how to optimize your circadian phase for performance and recovery.
A decade-by-decade clinical guide to pituitary MRI indications, prolactin and cortisol thresholds, incidentaloma workup, and society guideline recommendations for ordering and interpreting pituitary imaging across the lifespan.
Prolactin runs 2 to 29 ng/mL in premenopausal women, rising up to 40 ng/mL in luteal phase; levels above 25-40 ng/mL need pituitary workup.
What plasma renin activity levels predict cardiovascular and longevity outcomes? A guide to PRA interpretation, conventional reference ranges, and the evidence (and its limits) behind longevity-medicine target ranges.
Reverse T3 (rT3) is a non-functional thyroid metabolite that competes with active T3 at cell receptors. Learn the conventional normal range, the longevity-medicine target range, what drives rT3 elevation, and when treatment is warranted.
A guide to interpreting SHBG (extended) in the context of longevity medicine, including optimal target ranges, interaction with testosterone and estradiol, and what high or low SHBG means for long-term health outcomes.
A decade-by-decade clinical guide to sex hormone-binding globulin (SHBG): what counts as normal, what counts as optimal, and how age, sex, and metabolic health shift the target range.
Sex hormone-binding globulin (SHBG) binds testosterone and estradiol, directly controlling how much of each hormone is biologically active. This HealthRX.com guide covers the clinical reference range, longevity-medicine optimal targets, and how SHBG interacts with TRT, HRT, and metabolic disease.
Learn how fasting, carbohydrate intake, dietary fat, insulin, and specific nutrients drive SHBG up or down, and what the optimal SHBG range looks like for men and women.
A guide to thyroglobulin antibody (TgAb) reference ranges, longevity-medicine targets, thyroid autoimmunity staging, and post-thyroidectomy surveillance, with primary-source citations throughout.
Learn how food, fasting, macronutrients, and meal timing affect total testosterone blood levels, what the normal and optimal ranges are, and how to get an accurate lab draw.
A decade-by-decade clinical guide to TPO antibody levels, normal ranges, and optimal targets from your 20s through your 70s and beyond, with primary literature citations.
Trimethylamine N-oxide (TMAO) is a gut-derived cardiovascular risk marker with emerging longevity-medicine target ranges. Learn what optimal TMAO looks like, how it is measured, and what clinicians recommend to lower elevated levels.
Standard TSH reference ranges flag overt thyroid disease, not optimal function. This article explains where the narrower longevity-medicine target ranges come from, what the underlying evidence actually shows, and where the evidence stops short of proving that treating toward a tighter number improves outcomes.
How aerobic training, resistance exercise, overtraining, and body-composition changes affect TSH levels, what the optimal TSH range looks like for active adults, and when a shifting TSH reading warrants clinical action.
DEXA-derived VAT reference ranges, longevity-medicine targets, and clinical cut-points explained with an evidence-boundary map, sourcing caveats, and a decision framework for interpreting visceral fat results.
A deep dive into how endurance and resistance training affect vitamin B12 status, what the optimal serum range is for athletes and active adults, and when to supplement.
What VO2 max score do you actually need for a long, healthy life? This guide covers longevity-medicine target ranges, how the Watt test works, sex- and age-specific benchmarks, and the exercise prescriptions that move the needle.
A decade-by-decade guide to interpreting serum zinc levels, covering normal ranges, plausible age-related targets, and the questions a clinician should ask before treating a result as normal or abnormal.
Which medications raise, lower, or falsely shift DEXA-derived visceral adipose tissue (VAT) readings, what normal VAT ranges look like, and how to interpret results when a patient is on one of these drugs.
A guide to VAT measurement, normal ranges, metabolic risk interpretation, and the exact companion labs to order when DEXA-derived VAT is elevated.
A complete clinical guide to DEXA-derived visceral adipose tissue (VAT) measurement: what it measures, normal ranges, risk thresholds, and evidence-based strategies to reduce it.
Understand what your vitamin A (retinol) blood test actually means, the difference between the clinical 'normal' range and functional optimal levels, and what to do if your result is too low or too high.
How to read your vitamin B12 lab result at every age, from your 20s through your 80s. Covers optimal ranges, deficiency thresholds, metformin depletion, neuropathy risk, and the latest longevity-medicine consensus with primary citations.