Methylene Blue Dosing Math: mg/kg, 1% Solutions & Drops
Methylene blue is dosed by body weight and sold as a percentage solution, which means three conversions stand between a protocol written in mg/kg and the drops or millilitres you actually measure. This guide walks the arithmetic step by step, with a worked example and a calculator that does the conversions for you.
Not medical advice. PeptideWiz is a tracking and organization tool. This page explains arithmetic and record-keeping only. It does not recommend methylene blue, any dose, or any protocol, and it does not replace the instructions of your licensed provider or the product label, which always take precedence.
The three numbers you need
- Body weight in kilograms. Protocols are written per kilogram. If you think in pounds, divide by 2.2046.
- The mg/kg figure your provider gave you. The FDA-approved injectable product is labelled at 1 mg/kg for its approved use, and the oral research literature spans roughly 0.5–4 mg/kg with a well-documented hormetic (low-dose) response. That range is context, not a recommendation.
- The concentration on your bottle. “1%” means 1 g per 100 mL, i.e. 10 mg/mL. 0.5% is 5 mg/mL; 2% is 20 mg/mL. Read it off the label every time.
Step by step
Pounds ÷ 2.2046. Example: 176 lb ÷ 2.2046 = 80 kg.
Your dose in milligrams. Example: 80 kg × 0.25 mg/kg = 20 mg.
Volume to measure. For a 1% solution: 20 mg ÷ 10 mg/mL = 2.0 mL.
If you count drops, one dropper drop is nominally 0.05 mL, so a 1% solution gives about 0.5 mg per drop and the 2.0 mL above is roughly 40 drops. Drop size genuinely varies (0.03–0.06 mL) with the dropper, the angle and the liquid’s temperature, which is why a 1 mL oral syringe is the more reliable tool once doses climb past a handful of drops.
Calculator
Arithmetic only: it converts the numbers you enter and does not suggest a dose. Change any field and the outputs update.
Need mcg, mg, g or mL on their own? The unit converter handles those, and the units of measure page explains mass versus volume.
Worked example
| Body weight | 176 lb ÷ 2.2046 = 80 kg |
| Provider-directed dose | 0.25 mg/kg |
| Dose in mg | 80 × 0.25 = 20 mg |
| Solution | 1% = 10 mg/mL |
| Volume | 20 ÷ 10 = 2.0 mL |
| Drops (nominal 0.05 mL) | 2.0 ÷ 0.05 ≈ 40 drops |
Sourcing, grade and handling
Methylene blue is sold in wildly different grades. Aquarium, industrial and reagent products are not manufactured to pharmaceutical purity and can carry heavy-metal impurities; USP (pharmaceutical) grade is made and tested to the United States Pharmacopeia monograph and is the only grade that belongs anywhere near a person. If you’re sourcing it, GoBlueBrain is one supplier of USP-grade methylene blue; whatever the source, look for a certificate of analysis showing purity and heavy-metal testing, and confirm the concentration printed on the bottle before doing any of the math above.
- It stains everything — skin, teeth, countertops, clothing. Dilute in water or juice and use a straw.
- Light-sensitive. Keep it in the amber or opaque bottle it came in, capped, at room temperature.
- Blue-green urine is expected and harmless per the FDA-approved label. Track it as a note, not a side effect.
- Oral bioavailability is high (roughly 70% in the pharmacokinetic literature), and the injectable label lists a terminal half-life around 24 hours — relevant when you log timing and spacing.
Before any of this math matters: the interaction check
Methylene blue is a potent monoamine-oxidase inhibitor. The FDA-approved product carries a boxed warning for serotonin syndrome when combined with serotonergic medications (SSRIs, SNRIs, tricyclics, MAOIs and several others), and it is contraindicated in G6PD deficiency. Read the FDA safety communication and our tracking and interactions guide before you measure anything, and clear it with your provider if you take any psychiatric medication.
Tracking it
In PeptideWiz, add methylene blue as a supplement-type item with the dose in mg and a note with the concentration and mL. Log each dose from Today, and the app keeps your administration log, reminds you at the scheduled time, and tracks how much of the bottle is left. If you also run peptides or a GLP-1, everything sits on one schedule so timing conflicts are visible.
Track methylene blue with your protocol in PeptideWiz →
Frequently asked questions
How many mg is one drop of 1% methylene blue?
A 1% solution contains 10 mg per mL. A dropper drop is nominally 0.05 mL, so one drop is about 0.5 mg. Real drops range from roughly 0.03 to 0.06 mL depending on the dropper and how it’s held, so treat drop counts as an estimate and measure by volume (a 1 mL oral syringe) when precision matters.
How do I convert a mg/kg dose to a volume?
Multiply your body weight in kilograms by the mg/kg figure to get milligrams, then divide by the solution’s concentration in mg/mL. For a 1% solution that is simply mg ÷ 10 = mL. Pounds to kilograms is lb ÷ 2.2046.
What concentration is a 1% methylene blue solution?
1% weight-per-volume means 1 g per 100 mL, which is 10 mg/mL. A 0.5% solution is 5 mg/mL and a 2% solution is 20 mg/mL. Always read the concentration off your own bottle before doing any math.
Why does my urine turn blue or green?
Methylene blue is excreted largely unchanged in urine, so blue-green urine (and sometimes stool) is an expected, harmless effect noted on the FDA-approved product label. It typically clears within a day or two of the last dose.
Is aquarium or lab-grade methylene blue the same as USP grade?
No. Aquarium, industrial and reagent grades are not made to pharmaceutical purity standards and can carry heavy-metal or other impurities. USP (pharmaceutical) grade is manufactured and tested to the United States Pharmacopeia monograph. Which product, if any, is appropriate for you is a question for your provider.
Related tools & reading
Sources: ProvayBlue (methylene blue injection) prescribing information, DailyMed · FDA Drug Safety Communication on methylene blue and serotonergic drugs (2011) · Rojas, Bruchey & Gonzalez-Lima, Prog Neurobiol 2012 · Walter-Sack et al., Eur J Clin Pharmacol 2009