Tetracycline

Prescription ·Exploratory record · not publication-reviewed ·Updated July 13, 2026

Tetracycline is a broad-spectrum, bacteriostatic antibiotic of the tetracycline class used to treat a range of bacterial infections and inflammatory acne vulgaris. It is active against many gram-positive and gram-negative organisms as well as atypical pathogens such as Mycoplasma, Chlamydia, and Rickettsia. Its absorption is markedly reduced by chelation with divalent and trivalent cations found in dairy products, antacids, and mineral supplements.

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Publication status

Exploratory record, not a reviewed medical publication.

See the editorial and medical-review policies for the publication gate.

This generated database record has not completed a claim-level review by a qualified human medical reviewer. Bibliography links and evidence labels are not approval. The page remains available for reference and is excluded from search indexing.

In short

What the research says.

A quick, data-only summary. The full evidence, dosing, and sources are below.

Tetracycline is a broad-spectrum, bacteriostatic antibiotic of the tetracycline class used to treat a range of bacterial infections and inflammatory acne vulgaris. NutriStack rates the supporting evidence as strong. Common adult dosing is Adults: 250-500 mg orally every 6 hours (1-2 g/day); for acne, lower maintenance doses such as 250-500 mg once or twice daily are common, though a prescriber sets the actual dose. With long-term use it can deplete calcium, iron, magnesium. This profile indexes 3 sources.

What it's good for

Inflammatory acne vulgaris¹
Respiratory tract infections (e.g., those caused by Mycoplasma pneumoniae)
Rickettsial infections (e.g., Rocky Mountain spotted fever, typhus)
Chlamydial infections (e.g., trachoma, urethritis)
Helicobacter pylori eradication (as part of combination therapy)

What to watch for

Gastrointestinal upset (nausea, vomiting, diarrhea, epigastric burning)
Photosensitivity (exaggerated sunburn reaction)
Permanent tooth discoloration when used in children under 8 years or during tooth development
Known hypersensitivity to tetracyclines^1,2
Pregnancy (risk of fetal harm and maternal hepatotoxicity)

The bottom line

Evidence rating strong. Most-documented uses: inflammatory acne vulgaris, respiratory tract infections (e.g., those caused by mycoplasma pneumoniae), rickettsial infections (e.g., rocky mountain spotted fever, typhus). 3 sources indexed (1985–2012), with 0 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Tetracycline inhibits bacterial protein synthesis by reversibly binding to the 30S ribosomal subunit, where it blocks the attachment of aminoacyl-tRNA to the acceptor (A) site of the mRNA-ribosome complex. This prevents addition of new amino acids to the growing peptide chain, halting bacterial growth (a bacteriostatic effect). The drug enters bacterial cells partly by passive diffusion and partly by an energy-dependent active transport system that concentrates it intracellularly, accounting for its selectivity for bacterial over mammalian ribosomes. In acne, additional anti-inflammatory effects and suppression of Cutibacterium acnes contribute to clinical benefit.^2,1

Class

Tetracycline antibiotic

Absorption

Best on an empty stomach

Dosing

Dosing & protocol.

Common range

Adults: 250-500 mg orally every 6 hours (1-2 g/day); for acne, lower maintenance doses such as 250-500 mg once or twice daily are common

Recommended form

Oral capsule or tablet taken on an empty stomach (1 hour before or 2 hours after meals)

Absorption is significantly impaired by food, milk and other dairy products, and by divalent/trivalent cations including calcium, magnesium, iron, zinc, and aluminum (found in antacids and supplements) due to chelation. Take on an empty stomach, at least 1 hour before or 2 hours after meals, and separate from dairy, antacids, and mineral supplements by 2-3 hours.

Depletions

What it depletes.

Nutrients this medication can lower over time, and what to replace.

Calcium

Mild

Tetracycline chelates divalent and trivalent cations, forming insoluble, poorly absorbed complexes with calcium in the gut. Concurrent intake (especially with dairy) markedly reduces absorption of both the drug and dietary calcium; long-term use may modestly affect calcium status.

Replace Calcium citrateMonitor Serum calcium (ionized or albumin-corrected)Onset Acute reduction in absorption with each co-administered dose; clinically meaningful status effects only with prolonged use over weeks to months

Iron

Mild

Tetracycline and iron form mutual chelation complexes in the gastrointestinal tract, impairing absorption of both. Co-administration significantly lowers serum iron uptake and reduces tetracycline bioavailability.

Replace Ferrous sulfate (taken at least 2-3 hours apart from the drug)Monitor Serum ferritin and transferrin saturationOnset Per-dose impairment of iron absorption when taken together; relevant to iron status only with concurrent prolonged use or pre-existing deficiency

Magnesium

Mild

As a divalent cation, magnesium forms insoluble chelates with tetracycline in the gut, reducing absorption of both agents. Antacids and supplements containing magnesium are a recognized cause of this interaction.

Replace Magnesium glycinate (separated from the drug by 2-3 hours)Monitor Serum magnesiumOnset Acute, dose-by-dose reduction in absorption when co-ingested; minimal systemic depletion otherwise

Zinc

Mild

Zinc, a divalent cation, chelates with tetracycline to form complexes that are poorly absorbed, lowering bioavailability of both the antibiotic and zinc when taken concurrently.

Replace Zinc gluconate (taken several hours apart from the drug)Monitor Plasma or serum zincOnset Per-dose absorption interference; clinically significant zinc status changes are uncommon with short courses

Full Tetracycline depletion and interaction guide →

Safety

Full safety detail.

Side effects

Gastrointestinal upset (nausea, vomiting, diarrhea, epigastric burning)
Photosensitivity (exaggerated sunburn reaction)
Permanent tooth discoloration when used in children under 8 years or during tooth development
Esophageal irritation or ulceration if taken with insufficient water or before lying down
Candidal overgrowth (oral thrush, vaginal candidiasis)
Hepatotoxicity (especially with high doses or in pregnancy)
Pseudotumor cerebri (benign intracranial hypertension)
Hypersensitivity reactions and rash

Contraindications

Known hypersensitivity to tetracyclines^1,2
Pregnancy (risk of fetal harm and maternal hepatotoxicity)
Breastfeeding
Children under 8 years of age (risk of permanent tooth staining and effects on bone growth)
Use of outdated or degraded tetracycline (risk of Fanconi-like syndrome)^1,2
Concurrent use with isotretinoin or other systemic retinoids (increased risk of pseudotumor cerebri)

Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Meta-analyses & systematic reviews

1Antibiotics for acne vulgaris (systematic review)Cochrane Skin Group · Cochrane Database of Systematic Reviews · 2012
Oral tetracycline-class antibiotics reduce inflammatory acne lesions and are a standard treatment for moderate inflammatory acne.

Reviews & position papers

2Tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistancePMIDChopra I, Roberts M · Microbiology and Molecular Biology Reviews · 2001
Tetracyclines reversibly bind the 30S ribosomal subunit and block aminoacyl-tRNA binding to the A site, producing a bacteriostatic effect across a broad range of bacteria.
3Influence of food and milk on the absorption of tetracyclineVarious · Clinical Pharmacology and Therapeutics · 1985
Co-administration with milk, food, or polyvalent cation-containing products markedly reduces tetracycline bioavailability owing to chelation, supporting empty-stomach dosing.

FAQ

Common questions.

Quick answers about Tetracycline, drawn from the data on this page.

What is Tetracycline?

What is Tetracycline used for?

Commonly cited benefits of Tetracycline include: Inflammatory acne vulgaris; Respiratory tract infections (e.g., those caused by Mycoplasma pneumoniae); Rickettsial infections (e.g., Rocky Mountain spotted fever, typhus); Chlamydial infections (e.g., trachoma, urethritis); Helicobacter pylori eradication (as part of combination therapy). NutriStack rates the overall evidence as strong.

What is a typical dose of Tetracycline?

A typical adult dose of Tetracycline is Adults: 250-500 mg orally every 6 hours (1-2 g/day); for acne, lower maintenance doses such as 250-500 mg once or twice daily are common. The commonly recommended form is Oral capsule or tablet taken on an empty stomach (1 hour before or 2 hours after meals). These are general ranges, not personalized advice; confirm the right dose with a clinician.

What are the side effects of Tetracycline?

Reported side effects include gastrointestinal upset (nausea, vomiting, diarrhea, epigastric burning), photosensitivity (exaggerated sunburn reaction), permanent tooth discoloration when used in children under 8 years or during tooth development, esophageal irritation or ulceration if taken with insufficient water or before lying down, candidal overgrowth (oral thrush, vaginal candidiasis), hepatotoxicity (especially with high doses or in pregnancy). This is educational information; check with a healthcare professional before use.

How strong is the evidence for Tetracycline?

NutriStack rates this as Strong, meaning multiple high-quality meta-analyses or systematic reviews converge on the same finding. Full tier criteria are at https://nutristackapp.com/methodology/evidence-tiers.

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