Supplement stacks / Levothyroxine + Magnesium
Can You Take Levothyroxine with Magnesium?
Levothyroxine and Magnesium: one interaction flagged, scored 6/10 (medium risk). The count and score come from an AI-written analysis checked against our interaction rules, which can only make it stricter. Not medical advice.
Safety at a glance
This score comes from an AI-written analysis of the pair. Our interaction rules check it and can only make it stricter, never milder. Informational only: it can't account for your medications, conditions, or genetics.
What the AI-written analysis says
Taking Levothyroxine with Magnesium may lead to reduced absorption of Levothyroxine, which can affect thyroid hormone levels. It is recommended to separate the intake of these substances to minimize interaction risks.
Levothyroxine is a prescription medication. This page describes publicly documented interactions — it can't see your dose, your other prescriptions, or your labs. Discuss any supplement with the prescriber or pharmacist who manages this medication before combining.
Known interactions
Magnesium can interfere with the absorption of Levothyroxine, potentially leading to decreased effectiveness of the thyroid medication. It is advised to separate the intake by at least 4 hours.
Levothyroxine
From the AI-written analysis.
Generally safe when taken as prescribed; however, monitoring of thyroid levels is essential.
Typical dosage: As prescribed or as directed on the label
- Weight changes
- Increased heart rate
- Nervousness
- Insomnia
- Consult healthcare provider for dosage adjustments based on thyroid function tests.
Magnesium
From the AI-written analysis.
Generally safe for most individuals; caution in those with kidney disease.
Typical dosage: 200-400 mg daily.
- Diarrhea
- Nausea
- Abdominal cramping
- High doses can cause gastrointestinal upset; consult healthcare provider if you have kidney issues.
Timing
Take as prescribed — we do not schedule prescription medications. Follow the label or your prescriber, and ask your pharmacist before changing when you take it.
Watch out for
- Calcium, iron, magnesium, chromium, fibre supplements and antacids can lower how much thyroid medication (levothyroxine) is absorbed, which can leave your thyroid under-treated. Keep at least 4 hours between them. Prescribing information has levothyroxine taken on an empty stomach, typically 30-60 minutes before breakfast, so the mineral, fibre supplement, antacid or multivitamin is the one that fits later in the day; follow your prescriber or pharmacist on the levothyroxine itself. Ask for a TSH recheck if you start or change the mineral, the fibre supplement or the antacid.
Frequently asked questions
Can you take Levothyroxine and Magnesium together?
Levothyroxine and Magnesium: one interaction flagged, scored 6/10 (medium risk). The count and score come from an AI-written analysis checked against our interaction rules, which can only make it stricter. Not medical advice.
What score does the Levothyroxine and Magnesium combination get?
The Levothyroxine and Magnesium combination is scored 6/10 (medium risk). The score comes from an AI-written analysis checked against our interaction rules, which can only make it stricter. Not medical advice. Always confirm with a healthcare professional.
When should you take Levothyroxine and Magnesium?
Take as prescribed — we do not schedule prescription medications. Follow the label or your prescriber, and ask your pharmacist before changing when you take it.
What should you watch out for when combining Levothyroxine and Magnesium?
Calcium, iron, magnesium, chromium, fibre supplements and antacids can lower how much thyroid medication (levothyroxine) is absorbed, which can leave your thyroid under-treated. Keep at least 4 hours between them. Prescribing information has levothyroxine taken on an empty stomach, typically 30-60 minutes before breakfast, so the mineral, fibre supplement, antacid or multivitamin is the one that fits later in the day; follow your prescriber or pharmacist on the levothyroxine itself. Ask for a TSH recheck if you start or change the mineral, the fibre supplement or the antacid.
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Not medical advice
AI-written analysis generated August 28, 2026, checked by our interaction rules · How our analysis works