NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated July 13, 2026

Methimazole

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

Methimazole is the preferred antithyroid medication for the treatment of hyperthyroidism, including Graves' disease and toxic multinodular goiter. It inhibits thyroid hormone synthesis and is used to achieve euthyroidism prior to radioactive iodine therapy or surgery, or as long-term therapy for Graves' disease remission. It is generally preferred over propylthiouracil due to longer duration of action and fewer side effects.

Evidence tier
Strong
Indexed sources
10 2012–2025
Interactions
0
Category
Prescription
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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.

Methimazole is the preferred antithyroid medication for the treatment of hyperthyroidism, including Graves' disease and toxic multinodular goiter. NutriStack rates the supporting evidence as strong. Common adult dosing is 5–30 mg daily initially; maintenance 5–15 mg daily (as prescribed by your physician), though a prescriber sets the actual dose. This profile indexes 10 sources.

What it's good for
  • Effectively lowers thyroid hormone levels in hyperthyroidism6,10
  • Once-daily dosing in most patients
  • Graves' disease remission in 30–50% after 12–18 months of therapy3,1
  • Rapid biochemical response (2–6 weeks)
  • Preferred over PTU due to better safety profile4,8
What to watch for
  • Skin rash and urticaria
  • Arthralgia and myalgia
  • Gastrointestinal upset
  • Known hypersensitivity to methimazole or thioamides1,2
  • First trimester of pregnancy (propylthiouracil preferred due to methimazole teratogenicity)4,9

The bottom line

Evidence rating strong. Most-documented uses: effectively lowers thyroid hormone levels in hyperthyroidism, once-daily dosing in most patients, graves' disease remission in 30–50% after 12–18 months of therapy. 10 sources indexed (2012–2025), with 0 interaction records on file.

The science

How it works, mechanistically.

Core mechanism

Inhibits thyroid peroxidase (TPO), the enzyme responsible for the iodination of tyrosine residues on thyroglobulin and the coupling of iodotyrosines to form T3 and T4. This blocks new thyroid hormone synthesis without affecting existing stored hormone. Methimazole may also have immunomodulatory effects that contribute to Graves' disease remission.6,10

Class
Antithyroid Agent
Dosing

Dosing & protocol.

Common range
5–30 mg daily initially; maintenance 5–15 mg daily (as prescribed by your physician)
Recommended form
Oral tablet

Can be taken with or without food. Once-daily dosing is usually adequate due to prolonged intrathyroidal activity.5

Safety

Full safety detail.

Side effects

  • Skin rash and urticaria
  • Arthralgia and myalgia
  • Gastrointestinal upset
  • Agranulocytosis (rare but serious; 0.1–0.5%)
  • Hepatotoxicity (cholestatic pattern)
  • Hair loss
  • Taste abnormalities

Contraindications

  • Known hypersensitivity to methimazole or thioamides1,2
  • First trimester of pregnancy (propylthiouracil preferred due to methimazole teratogenicity)4,9
  • Prior agranulocytosis from thioamide therapy
  • Severe hepatic impairment
Sources

Sources, by evidence tier.

Numbered references. Citations throughout the page link here.

Meta-analyses & systematic reviews

4

Randomized controlled trials

1

Reference material

5
FAQ

Common questions.

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

What is Methimazole?

Methimazole is the preferred antithyroid medication for the treatment of hyperthyroidism, including Graves' disease and toxic multinodular goiter. It inhibits thyroid hormone synthesis and is used to achieve euthyroidism prior to radioactive iodine therapy or surgery, or as long-term therapy for Graves' disease remission. It is generally preferred over propylthiouracil due to longer duration of action and fewer side effects.

What is Methimazole used for?

Commonly cited benefits of Methimazole include: Effectively lowers thyroid hormone levels in hyperthyroidism; Once-daily dosing in most patients; Graves' disease remission in 30–50% after 12–18 months of therapy; Rapid biochemical response (2–6 weeks); Preferred over PTU due to better safety profile. NutriStack rates the overall evidence as strong.

What is a typical dose of Methimazole?

A typical adult dose of Methimazole is 5–30 mg daily initially; maintenance 5–15 mg daily (as prescribed by your physician). The commonly recommended form is Oral tablet. These are general ranges, not personalized advice; confirm the right dose with a clinician.

What are the side effects of Methimazole?

Reported side effects include skin rash and urticaria, arthralgia and myalgia, gastrointestinal upset, agranulocytosis (rare but serious; 0.1–0.5%), hepatotoxicity (cholestatic pattern), hair loss. This is educational information; check with a healthcare professional before use.

How strong is the evidence for Methimazole?

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.

Use this with your stack

Methimazole in NutriStack.

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NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.