Compass Laboratory Methylene Blue 0.5% is a liquid methylthioninium chloride solution supplied in a 50 mL amber glass dropper bottle. The manufacturer describes it as USP-grade, third-party tested and formulated without formaldehyde.

• 0.5% methylene blue solution.
• Equivalent to 5 mg of methylene blue per mL.
• 50 mL amber glass dropper bottle.
• USP-grade ingredient according to the manufacturer.
• Third-party tested for purity and concentration.
• Made in the USA.
• Formaldehyde-free according to the product label.

Do not use without medical guidance, especially if you take antidepressants, serotonergic medicines or opioids, have G6PD deficiency, are pregnant or breastfeeding, or have kidney disease