Methylene Blue
Methylene Blue is a research peptide in the Mitochondrial Electron Carrier class. At therapeutic doses methylene blue is reduced to leucomethylene blue, which donates electrons to methaemoglobin and converts ferric iron back to the ferrous form that can carry oxygen.
For research use only.
Key Facts
- CAS
- —
- Molecular Weight (MW)
- 319.9 g/mol
- Half-life
- —
- FDA status
- Approved
- Administration Route
- intravenous, oral
- Frequency
- —
- Last updated
- Aug 30, 2026
- Reviewed
- Aug 30, 2026
Vendor price snapshot
Price per mg is list price divided by vial size in milligrams when both are known from public vendor listings. Peptide Library does not sell peptides. Confirm live prices on the vendor site.
- Vendors listing this peptide
- 1
- Listed offers
- 1
- Price per mg range
- $10.00/mg
Research summary
Phenothiazine dye approved as an intravenous treatment for acquired methaemoglobinaemia. It is separately sold as a research chemical and studied at low doses for mitochondrial and cognitive endpoints, which are not approved uses.
Peptide Library's Methylene Blue profile summarises 5 cited studies listed in the Science section, the compound's regulatory status, and research-protocol parameters reported for it. It is a research reference, not medical advice.
Protocol
- Dosage Range
- —
- Frequency
- —
- Cycle
- —
- Administration Route
- intravenous, oral
- Reconstitution Guide
- —
Sequence & molecular data
| Molecular formula | C16H18ClN3S |
|---|---|
| Molecular weight | 319.9 g/mol |
| PubChem CID | 6099 |
| FDA UNII | 8NAP7826UB |
| ChEMBL | CHEMBL405110 |
| DrugBank | DB09241 |
Identifiers link to the public PubChem, FDA Substance Registration (UNII), ChEMBL and DrugBank records for the same entity.
Science
Mechanism of Action
At therapeutic doses methylene blue is reduced to leucomethylene blue, which donates electrons to methaemoglobin and converts ferric iron back to the ferrous form that can carry oxygen. At much lower concentrations it can act as an alternative electron carrier in the mitochondrial electron transport chain, cycling between oxidised and reduced forms and bypassing complex I/III blockade — the property behind its investigation in neurodegenerative and metabolic models. It is also a monoamine oxidase inhibitor, which is the basis of its serotonin syndrome risk.
Regulatory & research status
Methylene Blue is an FDA-approved product for specific labelled indications. Approval does not extend to the research contexts described on this page, and approved products are prescription medicines.
| FDA status | Approved |
|---|---|
| Research status | Approved product (see FDA status) |
| Availability | Prescription-Only |
| WADA (sport) | Unknown / Not Listed |
| Library classification | FDA-Approved |
Benefits
—
Potential Side Effects
No side effects listed yet for this entry.
Storage & stability
Lyophilized (freeze-dried) peptide powder is far more stable than the reconstituted solution. Keep sealed vials cold, dry and away from light; long-term storage is typically frozen, with short-term refrigeration for vials in use.
Once reconstituted in bacteriostatic water, keep the solution refrigerated, avoid repeated freeze–thaw cycles and agitation, and label the vial with the reconstitution date and concentration. Discard any solution that turns cloudy or shows particulates.
Degradation rates differ by sequence: peptides containing methionine, cysteine, asparagine or glutamine are more prone to oxidation and deamidation, so shelf life after reconstitution is compound-specific rather than universal.
Read the full guide: how to store peptides before and after reconstitution →
Source: Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharm Res. 2010;27(4):544–575. (PMID 20143256). General guidance for research handling; not product-specific instructions.
Methylene Blue: frequently asked questions
What is Methylene Blue?
Phenothiazine dye approved as an intravenous treatment for acquired methaemoglobinaemia. It is separately sold as a research chemical and studied at low doses for mitochondrial and cognitive endpoints, which are not approved uses.
How does Methylene Blue work?
At therapeutic doses methylene blue is reduced to leucomethylene blue, which donates electrons to methaemoglobin and converts ferric iron back to the ferrous form that can carry oxygen. At much lower concentrations it can act as an alternative electron carrier in the mitochondrial electron transport chain, cycling between oxidised and reduced forms and bypassing complex I/III blockade — the property behind its investigation in neurodegenerative and metabolic models.
Is Methylene Blue FDA approved?
Yes. Methylene Blue is approved by the FDA, and approved products are prescription medicines. Approval is always for specific indications studied in clinical trials, so an approved status does not mean the compound is approved for every use it is discussed for. Research-chemical material sold under the same name is not the approved product.
What peptides are similar to Methylene Blue?
Compounds most often compared with Methylene Blue include Elamipretide (SS-31), SS-20, MOTS-C and 5-Amino-1MQ. They are grouped by shared mechanism or research area rather than by equivalence, and their regulatory status and evidence base differ.
References
- Application of methylene blue for the prevention and treatment of COVID-19: A narrative review — Iran J Basic Med Sci, 2024External reference
- Why Methylene Blue Have to Be Always Present in the Stocking of Emergency Antidotes — Curr Drug Targets, 2018External reference
- Methylene Blue for Vasoplegic Syndrome — Heart Surg Forum, 2017External reference
- [Methylene blue] — Chudoku Kenkyu, 2008External reference
- Methylene-blue-associated encephalopathy — J Am Coll Surg, 2007External reference
Related research, comparisons & guides
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Compiled by Peptide Library Editorial · Reviewed Aug 30, 2026 · Updated Aug 30, 2026 · Version 1
This Methylene Blue profile is compiled from published literature (5 cited studies linked above), public regulatory records and chemical registries. It describes what research reports; it is not medical advice, and nothing here is a dosing recommendation for humans. Peptide Library does not sell peptides. Editorial policy · How profiles are compiled · Report an error
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