The terms, plainly.

0–9

8-OHdG

8-hydroxy-2-deoxyguanosine. A urinary marker of oxidative damage to DNA. When elevated, the free-radical load is winning against the body’s repair systems. A direct read on cumulative oxidative stress, measured on a urinary organic-acid profile.

ExposomicsEssay: Mitochondria: the powerhouses of your cells.

A

AA/EPA ratio

The ratio of arachidonic acid to eicosapentaenoic acid in the bloodstream. A practical read on the inflammatory tone of your fatty acid status. A lower ratio favors resolution; a higher ratio favors inflammation. Modifiable by diet and supplementation in weeks.

Mitochondria & Cellular Energy

Anaerobic threshold

The exercise intensity at which lactate begins accumulating in the blood faster than the body can clear it. Defines the upper boundary of sustainable effort. Below it, you can hold the work for hours; above it, minutes. Also called lactate threshold. Measured precisely on a CPET.

Mitochondria & Cellular Energy

ApoB

Apolipoprotein B. A count of atherogenic lipoprotein particles in the blood. In many studies it predicts cardiovascular risk at least as well as LDL cholesterol, and it is one of the numbers I weigh most on a lipid panel.

Metabolism & MetabolomicsEssay: A testosterone of 200 and an ApoB of 120: what…Essay: A fasting insulin of 12: what it can, and cann…

APOE

A gene with three common variants (E2, E3, E4) that shape how the body handles cholesterol, inflammation, and the brain’s response to aging. APOE4 carriers carry higher Alzheimer’s risk and benefit from earlier metabolic intervention. Tested once.

Epigenetics

B

Beta-glucuronidase

An enzyme produced by certain gut bacteria that can reactivate hormones and toxins after the liver has prepared them for elimination. Elevated activity slows clearance and recirculates compounds the body has already paid to remove. Measured on a stool test.

Gut-Immune Health

Bioidenticals

Hormone preparations with the same molecular structure the body produces (estradiol, progesterone, testosterone). Distinct from synthetic analogs. Second in the treatment hierarchy: lifestyle first, bioidenticals second, phytoceuticals third, pharmaceuticals as a last resort.

In the frameworkEssay: A testosterone of 200 and an ApoB of 120: what…

C

Calprotectin

A protein released by neutrophils. Stool calprotectin separates inflammatory bowel disease from irritable bowel syndrome and tracks gut inflammation precisely. Measured on a stool test.

Gut-Immune Health

CGM

Continuous glucose monitor. A small wearable sensor that measures interstitial glucose every few minutes for 10 to 14 days. Roughly four thousand readings paired with what you ate, when you slept, and what you did. The pattern is usually more revealing than the average.

Metabolism & MetabolomicsEssay: A fasting insulin of 12: what it can, and cann…

Chronobiology

The science of biological rhythms. How time of day shapes hormones, immunity, digestion, and repair, and what happens when those rhythms drift out of phase.

Chronobiology

Cortisol curve

The daily rhythm of cortisol secretion: high in the morning, declining through the day, low at night. When the curve goes out of phase (tired-and-wired evenings, wakeful 3 a.m. nights, energy crashes at consistent times), it explains a category of symptoms standard cortisol tests miss.

ChronobiologyEssay: The four pillars of sleep.Essay: Can meditation change your genes?

CPET

Cardiopulmonary exercise test. A maximal exercise test with a mask that measures every breath. Outputs your true VO2 max, your anaerobic threshold, and the fuel mix your body uses across exercise zones. Ground truth for cardiorespiratory fitness; watch-estimated VO2 max is a guess against it.

Mitochondria & Cellular Energy

D

Detoxification

The continuous biological process by which the liver and other organs neutralize and clear endogenous metabolites and exogenous chemicals. Phase I and Phase II liver pathways carry the bulk of the work; nutrient cofactors run each step. When the load exceeds the clearance, the burden shows up in symptoms.

ExposomicsEssay: Toxins in personal care products.

DEXA scan

Dual-energy X-ray absorptiometry. A whole-body scan that separates total mass into fat, lean tissue, and bone with millimeter precision. The image behind every meaningful metabolic conversation. Reads visceral fat and bone density at the same sitting.

Dysbiosis

An out-of-balance gut microbiome, often after antibiotics, ultra-processed diets, or chronic stress. It can contribute to inflammation, immune activity, and how hormones are metabolized.

Gut-Immune HealthEssay: Microbiome diversity and chronic disease.Essay: The gut-brain axis, explained.

E

Epigenetics

Chemical modifications that turn genes on or off without changing the underlying sequence. Methylation is one mechanism among several. The mechanism by which lifestyle, exposures, and time reshape gene expression across years.

EpigeneticsEssay: Epigenetics and cancer.Essay: What is epigenetics? Why it matters for your h…

Exposome

The total burden of environmental exposures across your lifetime. Air, water, plastics, pesticides, mold, heavy metals, and the chronic chemical inputs that shape every other system. Measurable.

ExposomicsEssay: What is actually in an executive physical?Essay: What is the exposome? And why I read it.

F

Fasting insulin

Insulin measured after an overnight fast. Moves first, years before HbA1c rises. The single number that catches the silent middle of metabolic decline, when standard glucose panels still look fine.

Metabolism & MetabolomicsEssay: A testosterone of 200 and an ApoB of 120: what…Essay: Concierge medicine, direct primary care, and n…

Ferritin

The protein that stores iron. The lab’s normal floor (15 ng/mL) is enough to prevent overt anemia but well below the level needed for energy, hair, mood, and exercise tolerance. I target above 70 for most patients.

Essay: A ferritin of 20: what a "normal" result can m…Essay: A testosterone of 200 and an ApoB of 120: what…

G

Glycemic variability

The minute-to-minute swing in blood glucose around the daily average. Two patients with identical HbA1c can have very different variability, and variability is what damages tissue over time. Best measured on a CGM.

Metabolism & Metabolomics

H

HbA1c

Hemoglobin A1c. A weighted three-month average of blood glucose, indirectly measured through how much sugar is glycated onto red blood cells. Useful but lagging. Fasting insulin and CGM data move first.

Metabolism & MetabolomicsEssay: A fasting insulin of 12: what it can, and cann…Essay: Do you need a concierge doctor if you feel fine?

Health Optimization Medicine

A physician-led clinical framework, abbreviated HOMe, built around an explicit definition of health rather than only a definition of disease. It interprets physiology longitudinally, in the context of a person's history, goals, the clinical evidence and standard medical assessment, identifies modifiable insufficiencies and imbalances where the evidence supports them, intervenes appropriately, and reassesses over time across seven biological pillars. The methodology inside this practice, and the one I am certified in.

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Health Optimization Practice

Abbreviated HOPe. The related framework through which non-clinical, non-physician practitioners apply health-optimization principles in their own settings. It is not the practice of medicine. Health Optimization Medicine (HOMe) is the physician application of the framework, which is what this practice uses.

In the framework

Healthspan

The years of your life spent in good health. Different from lifespan, which is just how long you live. Healthspan is the goal of Health Optimization Medicine. Longevity is its echo.

In the frameworkEssay: Mitochondrial health and aging.

HOMA-IR

A calculation from fasting glucose and fasting insulin that estimates how insulin-resistant you are. Most useful when HbA1c is still normal but insulin is climbing, which is the window I most want to catch.

Metabolism & MetabolomicsEssay: A fasting insulin of 12: what it can, and cann…

Homocysteine

An amino acid intermediate in methylation. When methylation is backed up (often from B-vitamin gaps or MTHFR variants), homocysteine accumulates and raises cardiovascular and cognitive risk. Cheap to measure, responsive to targeted nutrient support.

EpigeneticsEssay: Epigenetic clocks: what they measure, and what…Essay: What is epigenetics? Why it matters for your h…

hsCRP

High-sensitivity C-reactive protein. A marker of systemic inflammation. Elevations predict cardiovascular events and explain symptoms that other panels cannot.

Essay: An Lp(a) of 150: the lab you measure once, and…Essay: Shift work. Surviving and protecting your biol…

I

Insulin resistance

The state in which cells respond less to insulin’s signal to take up glucose. It can contribute to weight gain, energy and sleep problems, and many age-related diseases, and it often precedes a rising HbA1c by years.

Metabolism & MetabolomicsEssay: A testosterone of 200 and an ApoB of 120: what…Essay: A fasting insulin of 12: what it can, and cann…

L

Lp(a)

Lipoprotein (a). A largely genetically determined lipoprotein, usually measured once. Roughly one in five people has an elevated level, most without knowing it, and when present it materially changes how cardiovascular risk is read.

Essay: A testosterone of 200 and an ApoB of 120: what…Essay: An Lp(a) of 150: the lab you measure once, and…

M

Metabolomics

The study of the small molecules your cells produce as they make energy. A direct readout of how metabolism is actually running, upstream of the standard lipid and glucose panels.

In the frameworkMetabolism & MetabolomicsEssay: Concierge medicine, direct primary care, and n…Essay: How to tell a longevity doctor from a longevit…

Methylation

A chemical process that turns genes on and off, builds neurotransmitters, regulates detoxification, and recycles homocysteine. Genetic variants like MTHFR change how efficiently you methylate.

EpigeneticsEssay: Mitochondrial health and aging.Essay: Epigenetic clocks: what they measure, and what…

Methylmalonic acid (MMA)

A urine organic acid that accumulates when vitamin B12 is functionally low. Catches B12 deficiency in patients whose serum B12 looks normal. Read on urinary organic-acid profiles.

Metabolism & MetabolomicsEssay: What is metabolomics? A working definition for…

Microbiome

The community of bacteria, fungi, and viruses living in and on the body, especially in the gut. Shapes immune function, hormone metabolism, neurotransmitter production, and inflammation.

Gut-Immune HealthEssay: What is metabolomics? A working definition for…Essay: Microbiome diversity and chronic disease.

Mitochondria

The energy machinery inside almost every cell. Responsible for turning fuel into the cellular currency (ATP) that powers every other system. When they underperform, energy, cognition, and recovery follow.

Mitochondria & Cellular EnergyEssay: Mitochondrial health and aging.Essay: Fasting and mitochondrial biogenesis.

MTHFR

A common genetic variant affecting methylation efficiency. Slows the conversion of folate to its active form (5-MTHF), can elevate homocysteine, and changes how the body handles methylated B-vitamins. Tested once, factored in for life.

EpigeneticsEssay: What is epigenetics? Why it matters for your h…Essay: How sleep fuels your mitochondria.

O

Omega-3 index

The percentage of EPA and DHA in red blood cell membranes. Target is roughly 8 percent or higher. Strong predictor of cardiovascular outcomes and a useful gauge of dietary omega-3 sufficiency. The nutrient gap that reliably shows up in brain-fog presentations.

Mitochondria & Cellular EnergyEssay: What is actually in an executive physical?

Optimal range

A narrower target for a lab value than the reference range, used where the evidence supports one. Not every marker has an established optimal range, and a value outside one is a question to interpret in context, not a diagnosis. I read results against your own history, your goals, the evidence and standard medical assessment, and an optimal range is one input to that reading.

In the frameworkEssay: The four pillars of sleep.

Oxidative stress

The imbalance between free-radical production and the body’s antioxidant defenses. When free radicals win, mitochondria, DNA, and cell membranes take damage. Read through urinary markers like 8-OHdG and lipid peroxides.

Mitochondria & Cellular EnergyEssay: What is actually in an executive physical?Essay: Epigenetics and cancer.

P

Pancreatic elastase

A digestive enzyme produced by the pancreas. Low stool elastase points to pancreatic insufficiency and explains a category of bloating, weight loss, and nutrient malabsorption that other gut tests miss. Measured on a stool test.

Gut-Immune Health

Peptide hormones

Short chains of amino acids that function as signaling molecules in the body (growth hormone secretagogues, repair peptides, metabolic peptides). Distinct from steroid hormones in mechanism, half-life, and dosing.

Phytoceuticals

Botanical and nutrient-based compounds with measurable physiological effects, used as targeted therapeutics. Third in the treatment hierarchy: lifestyle first, bioidenticals second, phytoceuticals third, pharmaceuticals as a last resort.

In the frameworkEssay: A testosterone of 200 and an ApoB of 120: what…

Precision Health Plan

The written synthesis I produce for every patient: your history, records and results interpreted longitudinally and in context, with a prioritized plan for what is worth doing. It begins at the Precision Health Assessment and is revised over the course of ongoing care.

R

Reference range

The statistical band that holds the middle 95 percent of a laboratory's reference population. It is how medicine finds disease and keeps treatment safe, and a result inside it is good news. It is also a single point compared to a population, which is why I read it alongside your own prior results and history.

In the frameworkEssay: A testosterone of 200 and an ApoB of 120: what…Essay: How to tell a longevity doctor from a longevit…

Respiratory exchange ratio (RER)

The ratio of CO2 produced to oxygen consumed during exercise. Tells me what fuel you are burning at every intensity. Low RER means fat oxidation; high RER means carbohydrate. The crossover point is a marker of metabolic flexibility. Measured on a CPET.

Mitochondria & Cellular Energy

Reverse T3

An inactive form of the thyroid hormone T3. It can rise under stress, illness, or chronic inflammation. A normal TSH paired with a high reverse T3 is one pattern I consider when thyroid-type symptoms persist with an otherwise unremarkable panel.

ChronobiologyEssay: A TSH of 3.8 with symptoms: the four tests nob…Essay: Do you need a concierge doctor if you feel fine?

S

Secretory IgA (sIgA)

The antibody that lines mucosal surfaces, including the gut wall. The first immune barrier between the microbial world and the body. Low sIgA opens the door to dysbiosis and food reactions; high sIgA flags ongoing immune activation. Measured on a stool test.

Gut-Immune Health

SHBG

Sex hormone binding globulin. The protein that carries testosterone and estrogen in the bloodstream. A high SHBG locks up your sex hormones; a low SHBG releases them. Total hormone numbers are nearly meaningless without it.

Essay: A testosterone of 200 and an ApoB of 120: what…Essay: Do you need a concierge doctor if you feel fine?

T

T-score

A DEXA bone-density measurement comparing your bone density to a young adult reference. T-score above -1 is normal; -1 to -2.5 is osteopenia; below -2.5 is osteoporosis. Catches bone loss years before a fracture forces the conversation.

TCA cycle (Krebs cycle)

The central metabolic pathway inside the mitochondria where carbohydrates, fats, and proteins are processed into energy. Urinary intermediates of the cycle (citrate, malate, succinate, alpha-ketoglutarate) flag specific cofactor gaps when they back up. Measured on a urinary organic-acid profile.

Mitochondria & Cellular Energy

Time in range

The percentage of a CGM wear period your glucose stays inside the target band. A practical readout of glycemic stability that complements the average. I use tighter target bands than standard diabetes care.

Metabolism & Metabolomics

V

Visceral adipose tissue (VAT)

Metabolically active fat surrounding the abdominal organs. Distinct from subcutaneous fat under the skin in inflammatory tone, hormonal disruption, and cardiovascular risk. Measured directly on a DEXA scan; cannot be inferred from BMI.

VO2 max

The maximum volume of oxygen your body can use per kilogram of body weight per minute at peak exercise effort. The most powerful single predictor of all-cause mortality in the medical literature. Rises with training, falls with detraining. Measured directly on a CPET.

Mitochondria & Cellular EnergyEssay: Mitochondrial health and aging.