Famotidine

Oral tablet (10mg / 20mg / 40mg)Available in all 50 states

Marketing purposes only. Actual medications, if prescribed, are dispensed by a licensed pharmacy.

gut · h2 blocker

FamotidineFamotidine

Famotidine is a selective histamine H2-receptor antagonist. It reduces gastric acid secretion for GERD and peptic ulcer disease, and is also used at therapeutic doses as an adjunct in histamine-driven conditions such as mast-cell activation syndrome (MCAS).

Selective H2-receptor blockade, reduces gastric acid

Adjunctive H2 coverage in mast-cell / histamine conditions

Decades of clinical use; well-characterized safety profile

Generally well-tolerated; minimal drug interactions

No commitment · HSA/FSA eligibleNo commitment · HSA/FSA eligible

How it works

Mechanism of action

Famotidine reversibly blocks histamine H2 receptors on gastric parietal cells, reducing basal and stimulated gastric acid secretion. Onset is within 1 hour; duration is 10 to 12 hours at standard doses.

Unlike PPIs, famotidine does not inhibit the parietal-cell proton pump itself, and is associated with less of the long-term safety signal (B12, magnesium, gut dysbiosis) seen with chronic PPI therapy. In histamine-driven conditions like MCAS, H2 blockade can complement H1 antihistamines for fuller symptom coverage.

The baseline panel.

Every Marek client receives this baseline panel before a provider review. Your provider may add additional biomarkers based on your health history, symptoms, and goals, pulling from 1,000+ available markers. See more biomarkers →

Hormone Profile

12 markers

Sex hormones

Total TestosteroneLC/MS
Free TestosteroneEquilibrium Dialysis
Estradiol, Sensitive / UltrasensitiveLC/MS
Sex Hormone Binding Globulin (SHBG)
ProgesteroneLC/MSFemale panel
Prolactin
Luteinizing Hormone (LH)
Follicle-Stimulating Hormone (FSH)
hCG, Total, QuantitativeFemale panel, pre-menopause

Adrenals & neurosteroids

Cortisol
DHEA-S

Growth hormone / IGF-1

Insulin-Like Growth Factor I (IGF-1)

Thyroid Status

3 markers

Thyroid hormones

Thyroid Stimulating Hormone (TSH)
Free T4
Free T3

Heart Health

9 markers

Cardiovascular health

Total Cholesterol
HDL Cholesterol
LDL Cholesterol
LDL:HDL Ratio
VLDL Cholesterol
Triglycerides
Apolipoprotein-B (ApoB)
C-Reactive Protein, High Sensitivity (hsCRP)
Lipoprotein(a) (Lp(a))

Metabolism

3 markers

Insulin sensitivity

Blood Glucose
Fasting Insulin
HbA1c

Organ Function

26 markers

Liver & pancreas

AST
ALT
Bilirubin, Total
γ-Glutamyl Transferase (GGT)

Kidney function

BUN
Creatinine w/ eGFR

Comprehensive Metabolic Panel (CMP)

Glucose
Blood Urea Nitrogen (BUN)
Creatinine
eGFR
BUN/Creatinine Ratio
Sodium
Potassium
Chloride
Carbon Dioxide, Total
Calcium
Protein, Total
Albumin
Globulin, Total
Albumin/Globulin (A/G) Ratio
Alkaline Phosphatase (ALP)
AST
ALT

Prostate health

Prostate-Specific Antigen (PSA)Male panel
Free PSAMale panel
% Free PSAMale panel

Nutrient Status

31 markers

Vitamins & minerals

Vitamin D, 25-OHD (25-Hydroxy)
Magnesium, RBC

Iron status

Iron
Iron Saturation
TIBC
UIBC
Ferritin

Complete Blood Count (CBC)

White Blood Count (WBC)
Red Blood Count (RBC)
Hemoglobin (Hgb)
Hematocrit (HCT)
MCV
MCH
MCHC
Red Cell Distribution Width (RDW)
Platelets
Neutrophils
Neutrophils (Absolute)
Lymphocytes
Lymphocytes (Absolute)
Neutrophil/Lymphocyte Ratio
Monocytes
Monocytes (Absolute)
Eosinophils
Eosinophils (Absolute)
Basophils
Basophils (Absolute)
Immature Cells
Immature Granulocytes
Immature Granulocytes (Absolute)
NRBC, w/ Reflex for Immature Cells

Clinical evidence

The research behind Famotidine.

Famotidine for GERD: clinical pharmacology and outcomes review

Drugs (1989, updated reviews)

Reference review of famotidine's selectivity, pharmacokinetics, and clinical outcomes in acid-related disease. The drug demonstrates consistent symptom relief and ulcer-healing rates.

Read study →

Combined H1 and H2 antihistamine therapy in chronic urticaria

British Journal of Dermatology (1981)

Adding an H2 antihistamine (cimetidine/famotidine class) to standard H1 therapy improved control of chronic urticaria, supporting the dual-blockade rationale used in modern MCAS protocols.

Read study →

Safety profile

Monitoring & safety information.

Commonly reported side effects

Headache (uncommon)
Dizziness (uncommon)
Constipation or diarrhea (uncommon)

Less common but serious risks

Rare CNS effects in elderly or renally-impaired patients
Rare thrombocytopenia

Generally not appropriate for

Known hypersensitivity to famotidine or other H2 blockers
Severe renal impairment, dose reduction required
Pregnancy / breastfeeding, provider determination required

Typical monitoring

Renal function (eGFR), for dose adjustment
Symptom response
Concurrent medication review (limited interactions)

FAQ

Quick answers.

Eligibility, dose, and duration are determined by a partnered licensed medical provider based on your symptoms, labs, and medical history. A prescription is not guaranteed, your provider may recommend Famotidine, a different therapy, or further evaluation.

Famotidine is a selective H2-receptor antagonist. It reduces gastric acid secretion for GERD and peptic ulcer disease, and at therapeutic doses provides H2 coverage adjunctively in histamine-driven conditions like MCAS.

PPIs inhibit the parietal-cell proton pump directly and typically provide stronger acid suppression for severe GERD or healing-phase ulcer therapy. Famotidine is often preferred for maintenance, mild GERD, and as part of histamine-blockade protocols, with less long-term safety signal (B12, magnesium, microbiome).

Famotidine is generally well-tolerated. Mild headache, dizziness, and GI upset are the most commonly reported effects. Rare CNS effects can occur in elderly or renally-impaired patients, dose adjustment is part of the protocol when indicated.

View all FAQs

See all FAQs

Treatments are dependent on licensed clinical prescription. Client costs vary based on individual labs and panel in treatments and services.