The short answer
Liothyronine patient guidance advises keeping magnesium-containing oral products at least four hours from the thyroid dose. The clearest practical concern is a medicinal product such as a magnesium antacid; direct T3 interaction data for individual supplement salts remain limited.
What this answer covers
Oral liothyronine sodium tablets and swallowed magnesium products, particularly magnesium-containing antacids. No assumption that every magnesium salt, dose or injected preparation behaves alike.
- Supplement or preparation
- Magnesium
- Medication ingredient
- liothyronine
Why does the product type matter?
Magnesium can be supplied as an antacid, a laxative or a nutritional supplement. The Alberta liothyronine monograph names magnesium-containing products broadly, while the NCI reference confirms the antacid action of magnesium hydroxide. Neither establishes equal effects for all magnesium salts.
What schedule is advised?
The inspected liothyronine guidance uses at least four hours before or after the magnesium product. A pharmacist can check whether the specific preparation needs that precaution and fit it around the prescribed thyroid schedule. Count magnesium in combination antacids and supplements.
How strong is the evidence?
No magnesium-only liothyronine absorption trial was verified in the targeted search. Studies of levothyroxine, or of magnesium stearate used inside a manufactured T3 tablet, answer different questions. The current Cytomel absorption table does not explicitly list magnesium.
What should be monitored?
Liothyronine dosing is based on clinical response and appropriate thyroid tests. Tell the prescriber about starting or stopping regular magnesium use, particularly if symptoms or results change. Do not interpret an unchanged symptom on one occasion as proof that every combination or dose is unaffected.
Evidence and practical considerations
Absorption & effectiveness
Liothyronine patient guidance advises keeping magnesium-containing oral products at least four hours from the thyroid dose. The clearest practical concern is a medicinal product such as a magnesium antacid; direct T3 interaction data for individual supplement salts remain limited.
- Exact scope
- Oral liothyronine sodium tablets and swallowed magnesium products, particularly magnesium-containing antacids. No assumption that every magnesium salt, dose or injected preparation behaves alike. with oral liothyronine sodium providing the exact liothyronine active moiety
- Medication form and route
- oral
- Timing or duration
- During co-use; study-specific durations are retained in the source summaries. No universal duration or dose-response inferred.
What remains uncertain
- Clinical monograph precaution without direct salt-specific liothyronine human measurements. Formulation excipients and levothyroxine experiments were not treated as exact-pair proof.
Factors that may matter: exact supplement preparation and dose; oral versus nonoral medication route; other formula ingredients; patient thyroid status.
Read the supporting source summaries
Source 1: regulatory product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed oral liothyronine sodium tablets.
T3 dose depends on food, other medicines, clinical response and laboratory results. Table 1 explicitly names resins and bile-acid sequestrants, but does not name the mineral, fiber, soy or botanical pairs evaluated here.
How this applies: Confirms exact liothyronine active moiety, not levothyroxine. Supports monitored individualized treatment; mineral and botanical conclusions require other sources. Exact package scope: Oral liothyronine sodium tablets and swallowed magnesium products, particularly magnesium-containing antacids. No assumption that every magnesium salt, dose or injected preparation behaves alike.
Absence of a named interaction is not evidence of absence. The four-hour resin instruction cannot automatically be transferred to minerals or fiber.
Source 2: institutional patient medication monograph
myhealth.alberta.ca · Source check Sep 10, 2026
Population: People using oral liothyronine.
Monograph specifically names these products as potentially reducing liothyronine absorption and recommends at least four hours before or after.
How this applies: Exact medication is named. Guidance supports a cautious scheduling recommendation for listed oral products, not a measured clinical effect across every mineral preparation. Exact package scope: Oral liothyronine sodium tablets and swallowed magnesium products, particularly magnesium-containing antacids. No assumption that every magnesium salt, dose or injected preparation behaves alike.
Secondary patient guidance provides no underlying liothyronine-only trial, salt-specific effect size, threshold dose or validated four-hour comparison.
Source 3: government drug-identity reference
cancer.gov · Source check Sep 10, 2026
Population: Users of oral aluminum hydroxide and magnesium hydroxide suspension.
Identifies these hydroxides as acid-neutralizing antacid ingredients.
How this applies: Supports applying an antacid-class precaution to these acid-neutralizing preparations, not to all aluminum or magnesium exposures. Exact package scope: Oral liothyronine sodium tablets and swallowed magnesium products, particularly magnesium-containing antacids. No assumption that every magnesium salt, dose or injected preparation behaves alike.
No clinical cefuroxime data or isolated ingredient effect size.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Narrows the generic magnesium claim to a cautious oral-product assessment and makes the evidence gap explicit. | |
| Research summary published |
Article revision: c6f51289cda6b866
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.