Evidence-Based Supplement & Herb Guides

Hypoglycemia Hormone Test Panel: Insulin, C-Peptide, Proinsulin, Beta-Hydroxybutyrate, and Results

Understand a hypoglycemia hormone panel, including insulin, C-peptide, proinsulin, beta-hydroxybutyrate, critical-sample timing, result patterns, and next steps.

A hypoglycemia hormone panel is a group of blood tests collected while plasma glucose is genuinely low. The core measurements—glucose, insulin, C-peptide, proinsulin, and...

Insulin Blood Test: High, Low, Normal Range, Insulin Resistance, and Results

Learn how an insulin blood test is used, what fasting ranges mean, why insulin may be high or low, and how results relate to insulin resistance, diabetes, and hypoglycemia.

An insulin blood test measures the amount of insulin in serum or plasma at a specific moment. Insulin is released by pancreatic beta cells...

Insulin Resistance Blood Test Panel: Fasting Insulin, Glucose, C-Peptide, HOMA-IR, and Results

Understand an insulin resistance panel with fasting insulin, glucose, C-peptide, and HOMA-IR, including result patterns, limits, preparation, and follow-up.

An insulin resistance blood test panel combines fasting insulin and glucose with calculated HOMA-IR and, in some panels, C-peptide. The tests show how much...

Insulin/C-Peptide Ratio Test: Exogenous Insulin Use, Insulin Production, and Results

Learn how the insulin/C-peptide molar ratio is calculated and interpreted during hypoglycemia, including exogenous insulin patterns, endogenous secretion, assay limits, and follow-up tests.

The insulin/C-peptide ratio is a calculated laboratory value used mainly during the investigation of documented hypoglycemia. Insulin and C-peptide are released together when the...

Leptin Blood Test: High, Low, Obesity, Metabolic Health, and Results

Understand what a leptin blood test measures, why levels may be high or low, how obesity and leptin resistance affect results, and when specialized follow-up is appropriate.

A leptin blood test measures a hormone made mainly by fat cells that helps the brain assess long-term energy stores. Leptin usually rises as...

Pancreatic Hormone Test Panel: Insulin, C-Peptide, Proinsulin, Glucagon, and Results

Learn how insulin, C-peptide, proinsulin, and glucagon are used in a pancreatic hormone test panel, what result patterns mean, and why timing and assay context matter.

A pancreatic hormone test panel measures selected hormones made by islet cells, commonly insulin, C-peptide, proinsulin, and glucagon. These tests can help investigate documented...

Pancreatic Polypeptide Test: High Levels, Pancreatic Function, and Results

Learn what a pancreatic polypeptide test measures, why levels may be high, how fasting and age affect results, and when tumor or vagal-function follow-up is appropriate.

A pancreatic polypeptide test measures a 36-amino-acid hormone released mainly by specialized cells in the pancreas. Pancreatic polypeptide rises after eating, during exercise, and...

Proinsulin Blood Test: High Levels, Insulin Production, and Results

Learn what a proinsulin blood test measures, why levels may be high, how results help evaluate insulin production and hypoglycemia, and when insulinoma follow-up is needed.

A proinsulin blood test measures the precursor molecule that pancreatic beta cells process into insulin and C-peptide. Healthy beta cells convert most proinsulin before...

Somatostatin Blood Test: High Levels, Pancreatic Hormone, and Results

Understand what a somatostatin blood test measures, why levels may be high, how somatostatinoma affects glucose and digestion, and what follow-up testing is needed.

A somatostatin blood test measures a hormone that acts as a broad inhibitor of endocrine and digestive activity. Somatostatin is produced by delta cells...

Vasoactive Intestinal Peptide (VIP) Test: High Levels, Diarrhea, and Results

Learn when a VIP blood test is used for high-volume watery diarrhea, how high results support VIPoma, and why potassium loss, specimen handling, and imaging matter.

A vasoactive intestinal peptide test measures VIP, a neuropeptide that relaxes smooth muscle and stimulates secretion of water and electrolytes into the intestine. The...

Androgen Deficiency Blood Test Panel: Testosterone, SHBG, LH, FSH, Symptoms, and Results

Understand an androgen deficiency blood test panel, including testosterone, SHBG, free testosterone, LH, FSH, result patterns, causes, preparation, and follow-up.

An androgen deficiency blood test panel looks beyond a single testosterone number. It combines total testosterone with sex hormone-binding globulin (SHBG), free or calculated...

Androstenedione Test in Men: High, Low, Adrenal, Testicular, and Results

Learn what an androstenedione test in men measures, why levels may be high or low, how adrenal and testicular sources are evaluated, and which follow-up tests help.

An androstenedione test measures a steroid hormone made by both the adrenal glands and testes. Androstenedione is weaker than testosterone, but it is an...

Anti-Mullerian Hormone (AMH) Test in Men: Testicular Function and Results

Understand AMH testing in men, including Sertoli-cell function, age-related ranges, low and high results, infertility and azoospermia uses, limitations, and follow-up tests.

An anti-Müllerian hormone (AMH) test in males mainly reflects Sertoli-cell activity in the testes. AMH is best known for its role in fetal male...

Bioavailable Testosterone Test: Low Levels, Normal Range, SHBG, and Results

Learn how bioavailable testosterone is measured, how SHBG changes results, what low levels may mean, when testing is useful, and which follow-up tests guide diagnosis.

A bioavailable testosterone test estimates the testosterone that is free or loosely bound to albumin and therefore more readily available to tissues. It excludes...

DHEA-S Test in Men: High, Low, Adrenal Androgens, and Results

Learn what a DHEA-S test in men measures, why levels may be high or low, how age and supplements affect results, and which adrenal tests guide follow-up.

A DHEA-S test measures dehydroepiandrosterone sulfate, the most abundant circulating adrenal androgen. In men, DHEA-S comes almost entirely from the adrenal glands, making it...

Dihydrotestosterone (DHT) Test: High, Low, Hair Loss, Prostate, and Results

Understand DHT testing, including high and low results, 5-alpha-reductase inhibitors, hair loss, prostate effects, assay limitations, and appropriate follow-up.

A dihydrotestosterone (DHT) test measures a potent androgen made when the enzyme 5-alpha-reductase converts testosterone into DHT. The hormone is essential for fetal development...

Estradiol (E2) Test in Men: High, Low, Normal Range, and Hormone Balance

Understand estradiol testing in men, including sensitive assays, high and low causes, testosterone and SHBG patterns, gynecomastia, bone health, and follow-up.

An estradiol (E2) test in men measures the most biologically active form of estrogen. Most male estradiol is created when aromatase converts testosterone into...

Follicle-Stimulating Hormone (FSH) Test in Men: Sperm Production, Fertility, and Results

Understand the FSH test in men, including high, low, and normal results, sperm-production patterns, infertility causes, related hormones, and next steps.

A follicle-stimulating hormone (FSH) test in men helps assess pituitary signaling to the sperm-producing tissue of the testes. FSH acts on Sertoli cells, which...

Free Testosterone Test: Low Levels, Normal Range, SHBG, Symptoms, and Results

Understand when a free testosterone test is useful, how SHBG and test method affect results, what low or high levels may mean, and which follow-up tests help confirm the cause.

A free testosterone test estimates the small share of testosterone that is not tightly bound to sex hormone-binding globulin (SHBG). It can clarify hormone...

Gynecomastia Hormone Test Panel: Testosterone, Estradiol, LH, hCG, Prolactin, and Results

Learn what a gynecomastia hormone panel measures, how testosterone, estradiol, LH, hCG, and prolactin patterns are interpreted, and when imaging or urgent assessment is needed.

A gynecomastia hormone test panel helps investigate true glandular breast enlargement in a male, especially when it begins suddenly, is painful, occurs before or...