Longevity · Dosing reference

Methylene Blue dosage

Dosing as the FDA label states it, how long trials ran, and the arithmetic for working with vials.

FDA-approvedAHuman trial evidenceFDA label

Full research page Cycle-length evidence Compare Prefer Amiravo on Google

Regulatory status: FDA-approved
Human amounts: 1 mg/kg (FDA label); repeat 1 mg/kg once if needed
Route studied: Intravenous over 5 to 30 minutes
Frequency: Single dose, with at most one repeat after 1 hour (maximum two doses)
Half-life: Approximately 24 hours
Evidence grade: Grade A · Human trial evidence
Vial sizes on the market: Not recorded
Other forms seen: Oral solution (drops) 0.5% · Oral solution (drops) 1% (10 mg/mL) · Oral solution (drops) 2%

What Methylene Blue is

Methylene blue is a thiazine dye and oxidation-reduction agent, not a peptide. It is FDA-approved as PROVAYBLUE injection for treating acquired methemoglobinemia in children and adults, with a boxed warning for serotonin syndrome when combined with serotonergic drugs or opioids, and it is contraindicated in G6PD deficiency. It has also been studied in small human trials, for example in septic shock and brain imaging; this entry summarizes the label and selected studies for research reference only.

Methylene blue promotes non-enzymatic redox conversion of methemoglobin to hemoglobin: it is first converted to leucomethylene blue by NADPH reductase, and leucomethylene blue reduces the ferric iron of methemoglobin to the ferrous state ^1. Monoamine oxidase inhibition The label cites literature describing methylene blue as a potent reversible inhibitor of monoamine oxidase, which underlies the risk of serotonin… How it works →

Key evidence

PROVAYBLUE label, Clinical Studies (NCT03395223, NCT03542760) · 2025 · Humans (adults with acquired methemoglobinemia, n=31)
Of 28 subjects with a baseline methemoglobin value (mean 18.4%), 26 (92.9%) had at least a 50% reduction at the first post-dose assessment (median 2.7 hours) ^1. ¹
Ibarra-Estrada et al., Crit Care · 2023 · Humans (patients with septic shock, Sepsis-3)
Time to vasopressor discontinuation was 69 versus 94 hours; vasopressor-free days, ICU stay and hospital stay favoured methylene blue; mortality and ventilator days were similar; no serious adverse effects related to methylene blue were reported ^4. ⁴
Rodriguez et al., Radiology · 2016 · Humans (healthy adults aged 22 to 62, n=26)
Methylene blue increased insular cortex response during a sustained-attention task and prefrontal, parietal and occipital responses during a short-term memory task, with a 7% increase in correct retrieval responses ^3. ³

All studies on the research page

Dosing as stated on the FDA label

PROVAYBLUE for acquired methemoglobinemia: administer 1 mg/kg intravenously over 5 to 30 minutes. If the methemoglobin level remains greater than 30% or if clinical signs and symptoms persist, a repeat dose of 1 mg/kg may be given one hour after the first dose. If methemoglobinemia does not resolve after 2 doses, consider initiating alternative interventions. ¹
Renal impairment: the recommended dosage in patients with moderate or severe renal impairment (eGFR 15 to 59 mL/min/1.73 m2) is a single dose of 1 mg/kg; no adjustment is recommended for mild renal impairment. ¹
Per the label, the recommended dose is 1 mg/kg (lower or greater doses are not recommended), the maximum recommended number of doses is two, ensure patent venous access, do not administer subcutaneously, and the injection may be diluted in 50 mL 5% Dextrose Injection (avoid sodium chloride solutions). ¹
Dosage forms per the label: 50 mg/10 mL and 10 mg/2 mL (5 mg/mL) single-dose ampules or vials; strength is expressed in terms of the trihydrate. ¹
In the label's clinical studies, most doses administered were 1 mg/kg (82.9%), with doses from 0.78 mg/kg to 2 mg/kg; two patients received two doses and one received three ^1.
In SHOCKEM-Blue (NCT04446871), patients with septic shock received an intravenous infusion of 100 mg methylene blue in 500 mL of 0.9% sodium chloride over 6 hours once a day for 3 doses, or a saline placebo infusion ^4,5.
In the fMRI study, healthy adults received a single low oral dose of methylene blue or placebo, with imaging 1 hour later; the amount is not stated in the abstract ^3.

How long did human studies run?

Label: one dose, with at most one repeat dose one hour later; consider alternatives if not resolved after 2 doses ^1.
Septic shock trial: once daily for 3 days ^5.

Cycle-length evidence for Methylene Blue

Contraindications on the label

Contraindicated in G6PD deficiency and in severe hypersensitivity to methylene blue or other thiazine dyes ^1.
Avoid with SSRIs, SNRIs, MAOIs, opioids and other serotonergic drugs (boxed warning) ^1.
Single dose only in moderate or severe renal impairment; breast-feeding to be stopped for up to 8 days after treatment ^1.

Side effects reported in studies

Headache, hypokalemia, diarrhea, hypomagnesemia, myoclonus, nausea, seizure-like phenomena
2% or more (each) · 31 adults with acquired methemoglobinemia (label) ¹
Serotonin syndrome
Reported with methylene blue class products, mostly with serotonergic drugs; some fatal · Label boxed warning ¹
Hemolytic anemia
Can occur; onset may be delayed 1 or more days · Label warnings; severe in G6PD deficiency ¹
Anaphylaxis and severe hypersensitivity
Reported with methylene blue class products · Label warnings ¹
Hypotension, wheezing, reduced oxygenation
Reported at single doses of 3 mg/kg or more of methylene blue class products · Label overdosage section ¹
Blue discoloration of skin and body fluids; phototoxicity
Not quantified · Label patient counseling and class adverse reactions ¹

Full adverse-event data

Supplies and handling

Lyophilized vial
Sealed vial with the freeze-dried cake. Check the label, lot and the certificate of analysis before opening.
Sterile diluent
The diluent named on the product documentation. Bacteriostatic water contains benzyl alcohol; sterile water does not.
Graduated syringes
Sized to the volume being measured. U-100 insulin syringes are graduated in units where 100 units = 1 mL.
Alcohol prep pads
For wiping vial stoppers before each puncture.
Nitrile gloves
Clean gloves for aseptic handling.
Sharps container
Puncture-resistant container for used needles.

Step-by-step reconstitution guide Storage and transport accessories

Storage

Per the PROVAYBLUE label: store at 20 to 25 degrees C (excursions 15 to 30 degrees C permitted); do not refrigerate or freeze; keep the ampule or vial in the original package to protect from light ^1.

Lyophilized (unmixed) vials: typically stored cold and dry, away from light, as the documentation directs. Many are stable longer frozen.
Reconstituted vials: typically refrigerated (about 2–8 °C), protected from light and not frozen.
Bacteriostatic water contains benzyl alcohol, which inhibits bacterial growth in multi-use vials; sterile water has no preservative.

Handling mistakes and troubleshooting

Added the wrong volume of diluent: The concentration changes, not the amount of compound in the vial. Recalculate with the volume actually added and relabel the vial.
Shook the vial and it foamed: Let it settle in the refrigerator. Foam is a sign of agitation; some peptides aggregate when shaken. Note it on the label.
The solution is cloudy or has particles: Do not use it. Cloudiness can indicate incomplete dissolution, contamination or degradation. Record the lot and contact the supplier with the certificate of analysis.
The powder cake looks melted or shrunken before reconstitution: This can indicate the vial was exposed to heat or moisture. Record the lot and condition on arrival.
Liquid sprayed back when the needle was removed: Pressure built up in the vial. Withdraw a small volume of air while adding diluent to keep pressure neutral.

Regulatory status

Status: Approved by the FDA as PROVAYBLUE (methylene blue) injection, NDA 204630, original approval 8 April 2016, for the treatment of pediatric and adult patients with acquired methemoglobinemia ^1,2.
United States (FDA): Approved under NDA 204630 (PROVAYBLUE, original approval 8 April 2016) per the Drugs@FDA application record ^2; the current label was reviewed from DailyMed ^1.
Sport (WADA): Methylene blue is not named on the WADA 2026 Prohibited List ^7.

Status varies by country and changes over time. How we describe regulatory status.

Methylene Blue compared with related compounds

Compound	Status	Evidence	Human amounts	Half-life
Methylene Blue	FDA-approved	A	FDA label	Approximately 24 hours
NAD+	Not approved — research use only	B	None established	—
L-Glutathione	Not approved — research use only	B	None established	—
Epithalon	Not approved — research use only	C	None established	—
N-Acetyl Epithalon Amidate	Not approved — research use only	—	None established	—
SS-31 (Elamipretide)	FDA-approved	A	FDA label	—

Frequently asked questions

What doses of Methylene Blue have been studied in humans?

Methylene Blue is FDA-approved, so the label states the dosing for the approved product. This page quotes it, with citations. It does not apply to research-grade material.

Is there an established Methylene Blue cycle length?

No cycle length or break has been established. Human studies administered Methylene Blue for the periods listed on this page; those are study durations, not a recommended course.

How much bacteriostatic water should be added to a Methylene Blue vial?

There is no compound-specific volume. The diluent volume only sets the concentration: concentration = mass in the vial ÷ volume added (for example, 10 mg in 2 mL gives 5 mg/mL). The calculator on this page shows the arithmetic for any combination.

How many units is a given amount on an insulin syringe?

On a U-100 syringe, 100 units = 1 mL. Units for an amount = amount ÷ (concentration per unit). The calculator converts any amount you enter at the concentration you choose; a unit is a volume mark, not an amount of compound.

What is the half-life of Methylene Blue?

Approximately 24 hours

Is Methylene Blue FDA-approved?

FDA-approved. Approved by the FDA as PROVAYBLUE (methylene blue) injection, NDA 204630, original approval 8 April 2016, for the treatment of pediatric and adult patients with acquired methemoglobinemia ^1,2.

References

PROVAYBLUE (methylene blue) injection, USP, for intravenous use. Prescribing information, American Regent / Provepharm (SPL published June 12, 2025) DailyMed (FDA label). 2025
Drugs@FDA application record for PROVAYBLUE (methylene blue), NDA 204630, original approval 8 April 2016 openFDA / Drugs@FDA. 2026
Multimodal Randomized Functional MR Imaging of the Effects of Methylene Blue in the Human Brain Radiology. 2016
Early adjunctive methylene blue in patients with septic shock: a randomized controlled trial Crit Care. 2023
Methylene Blue in Early Septic Shock (SHOCKEM-Blue, NCT04446871) ClinicalTrials.gov. 2021
PubChem compound record for methylene blue (CID 6099; CAS 61-73-4) PubChem. 2026
International Standard: Prohibited List 2026 World Anti-Doping Agency. 2026

Last reviewed October 23, 2026 by the Amiravo editorial team. Editorial policy · Report an error