Learn what the DUTCH test measures, what high or low results mean, and which diet, lifestyle, and clinical interventions have the strongest evidence for improving adrenal and sex-hormone metabolite patterns.
Learn the difference between a 'normal' ESR lab result and a functionally optimal level, what high or low values signal, and how to bring your inflammatory markers into a healthy range.
Learn how acute and chronic exercise affect ESR, what the optimal ESR range looks like for active adults, and when an abnormal result warrants clinical follow-up.
How TRT, HRT, aromatase inhibitors, SERMs, and other drugs shift estradiol (sensitive) levels, with target ranges, monitoring schedules, and dose-adjustment guidance backed by primary literature.
How aerobic exercise, resistance training, body composition, and overtraining affect estradiol (sensitive) levels in men on TRT, women on HRT, and perimenopausal women. Includes normal ranges, general targets, and clinical guidance.
Ferritin test codes, normal ranges by sex, and thresholds: under 30 ng/mL signals deficiency, over 500 ng/mL needs workup for overload or disease.
How aerobic exercise, resistance training, and weight loss affect FibroScan (VCTE) liver stiffness and CAP scores. Includes normal ranges, MASLD staging cutoffs, and clinical guidance.
How diet, fasting, and macronutrient intake shift free testosterone levels, what the optimal range looks like, and how to time your blood draw for accurate TRT dose titration.
A guide to FSH reference intervals, longevity-medicine targets, perimenopause confirmation, fertility assessment, and when to act on an out-of-range result.
A guide to GGT lab values: what normal, high, and low results mean, how GGT affects prescribing decisions for GLP-1s, TRT, HRT, and statins, and the fastest evidence-based ways to lower an elevated result.
Learn what your GGT (gamma-glutamyl transferase) lab result means, what causes high or low levels, and what steps to take based on your number. Reviewed by board-certified physicians.
Learn how food intake, fasting duration, blood glucose, free fatty acids, and macronutrient composition alter growth hormone stimulation test results, normal ranges, and clinical interpretation.
Learn what ghrelin is, what normal ghrelin levels look like, and which paired lab tests give clinicians the full metabolic picture. Includes dosing context, GLP-1 interactions, and an original clinical ordering framework.
Learn what GlycoMark (1,5-AG) actually measures, why the lab 'normal' range misses early glucose dysfunction, and what functional optimal looks like for metabolic health.
A guide to HOMA-IR reference ranges, longevity-medicine targets, how the score is calculated, and what to do when your result is too high.
Women in their 50s typically see rMSSD trend down from the 35-70 ms range of their 40s toward 20-45 ms in their 60s, based on HUNT Fitness Study data.
HRV meaning explained: 20 to 80 ms RMSSD is typical for healthy adults, over 100 ms for athletes, below 20 ms linked to higher cardiovascular risk.
A guide to high-sensitivity C-reactive protein testing: who needs it, what the numbers mean, how cardiovascular risk is classified, and what interventions actually move the marker.
High-sensitivity troponin (hs-troponin) is now a longevity biomarker, not just a heart-attack test. Learn the evidence-based target ranges, what levels predict 10-year cardiovascular risk, and how clinicians interpret results in longevity medicine.
A decade-by-decade clinical guide to IGF-1 reference ranges, optimal targets, and what low or high values mean for growth hormone therapy, longevity, and metabolic health.
A complete clinical guide to IGFBP-3 testing, what the protein does, what the lab result means, normal ranges by age and sex, causes of high and low values, and how to interpret results alongside IGF-1.
Learn what iron, TIBC, and transferrin saturation mean, what normal ranges look like, and the evidence-based steps you can take to correct iron deficiency or overload.
Everything you need to know about the standard lipid panel: what it measures, at-home and finger-prick testing options, normal ranges, optimal cardiovascular targets, and how to act on your results.
A guide to every major drug class that raises, lowers, or falsely shifts lipid panel values, with real doses, named trials, and guidance on how to interpret results while on medication.
Learn what your LP-IR score means, what normal and high values indicate, and evidence-based steps to lower insulin resistance as measured by NMR lipoprotein testing.
How intense exercise affects magnesium status, why serum magnesium can miss cellular depletion, what RBC magnesium testing can and cannot tell you, and how repletion is typically approached.
A clinical guide to salivary melatonin profile testing at home, covering collection timing, dim-light melatonin onset (DLMO), reference ranges, finger-prick alternatives, and what the result can and cannot tell a clinician.
A decade-by-decade guide to NT-proBNP normal ranges, age-adjusted cut-offs, and what rising or falling values mean for heart failure risk and longevity monitoring.
Learn how aerobic training, resistance exercise, and endurance sports affect NT-proBNP levels, what the normal and optimal ranges mean, and how to interpret results in active adults.
Learn what the Omega-3 index measures, what a healthy range looks like, and which specific doses, foods, and strategies have clinical trial support for raising EPA+DHA in red blood cells.
A clinical guide to serum progesterone testing: which medications can raise or lower results, reference ranges by cycle phase and sex, and how to interpret abnormal values in the context of HRT, fertility treatment, and TRT.
Learn how progesterone medications change your lab values, what the optimal range looks like in the luteal phase versus HRT, and how clinicians interpret results across different dosing protocols.
Learn what reverse T3 is, what a normal range looks like, what high or low levels mean clinically, and how to interpret your results alongside free T3 and TSH.
Evidence-based selenium reference ranges for longevity medicine, thyroid conversion, antioxidant enzyme function, and cardiovascular health. Includes optimal targets, deficiency cutoffs, toxicity thresholds, and how to interpret your serum and plasma results.
Certain medications falsely raise or suppress SIBO breath test hydrogen and methane readings. Learn which drugs interfere, how long to hold them, and what normal and optimal ranges look like.
Follow a low-fermentation diet for 1-2 weeks, then fast 12 hours on water only. Skipping this prep can cause false-positive hydrogen or methane results.
A clinically grounded guide to at-home and finger-prick total testosterone testing: normal ranges, optimal targets, collection methods, accuracy data, and when to escalate to venipuncture.
A clinical guide to the urine albumin-to-creatinine ratio (UACR): what it measures, normal ranges, drugs that can raise or lower results without true kidney change, and how to interpret a single value correctly.
How sodium intake, potassium, fasting duration, posture, and diet composition shift aldosterone levels, and what the optimal reference range actually looks like for clinical interpretation.
Age-specific ALT reference ranges explained by decade, including optimal vs. Laboratory-normal thresholds, sex differences, and what rising ALT means at each life stage.
Exercise can raise ALT 2 to 3x normal within 48 hours, peaking at 12-48h and resolving in 72-96h. Learn how to tell muscle-related rises from true liver issues.
A guide to how statins, PCSK9 inhibitors, ezetimibe, fibrates, niacin, GLP-1 agonists, and other drugs change ApoB levels, with target ranges, trial data, and practical dosing context.
How diet, fasting, and specific foods shift ApoB concentrations, why ApoB outperforms LDL-C as a cardiovascular predictor, and what target levels current guidelines recommend.
How diet, fasting, and exercise affect AST levels, what the optimal AST range is, and when elevated readings signal true liver stress versus normal physiological variation.
See normal ABPM thresholds by decade: daytime under 135/85, 24-hour under 130/80, nighttime under 120/70, plus dipper status and masked hypertension rates.
Board-reviewed guide to 24-hr ambulatory BP target ranges for longevity medicine, covering optimal daytime, nighttime, and dipping thresholds with primary literature citations.
A guide to CMP reference ranges, longevity-medicine optimal targets, and how to interpret glucose, kidney, liver, and electrolyte markers for long-term health.
A guide to DEXA body composition testing, what your results mean, how at-home and low-cost alternatives compare, and how to think about fat mass, lean mass, and bone density targets by age and sex.
Standard lab ranges flag fasting glucose at 100 mg/dL. Longevity medicine sets the bar lower. Learn what optimal fasting glucose looks like, what the trials show, and how clinicians use this number to reduce all-cause mortality risk.
A clinical deep-dive into fasting triglyceride reference ranges, longevity-medicine targets, metabolic syndrome thresholds, and MASLD risk. Includes guideline cut-points and a practical decision framework.
Fasting triglycerides under 100 mg/dL are optimal; 150+ signals risk. See how refined carbs, alcohol, and fasting length affect your results.
How training affects iron stores, how to interpret ferritin with other iron tests, and what evidence supports diet, oral iron, IV treatment and monitoring.
How aerobic exercise, resistance training, caloric restriction, and overtraining affect Free T3 levels, plus the normal and optimal ranges, signs of suppression, and when to retest.
A guide to ghrelin normal ranges, longevity-medicine targets, how GLP-1 therapies affect ghrelin, and what your lab result means for appetite control and metabolic health.
A guide to GlycoMark (1,5-anhydroglucitol) reference ranges, longevity-medicine target ranges, and what the evidence does and does not establish about postprandial glucose excursions and long-term metabolic health.
Evidence-based grip strength target ranges for longevity medicine, sarcopenia screening, and mortality risk. Includes sex- and age-specific norms, testing protocols, and clinical action thresholds from primary literature and society guidelines.
A guide to HbA1c target ranges in longevity medicine, covering ADA and AACE guidelines, optimal ranges for non-diabetic adults, GLP-1 monitoring, and the evidence from ACCORD, UKPDS, and EDIC trials.
What is the optimal hematocrit for longevity? Learn evidence-based target ranges, TRT polycythemia thresholds, and how to interpret your results with primary-source citations.
Learn how diet, hydration, fasting, iron intake, and TRT affect hematocrit levels. Includes normal ranges, optimal targets, and evidence-based guidance from primary literature.
How aerobic training, strength work, altitude exposure, and testosterone therapy each shift hematocrit, what the normal and optimal ranges are, and when a rising value signals danger.