Five things to check in a minute, and the myths to ignore.

• Five checks take about a minute. USP grade, the amount in mg, a lab report you can open, a product sold by the brand itself, and powder that turns water deep blue.
• Disease claims are a red flag. A methylene blue supplement that makes them is breaking the rules for supplements.
• The grade matters more than the form. Capsules give a fixed amount. Liquid gives fine control, but it stains.

Important: Methylene blue has documented interactions with serotonergic medications including SSRIs and MAOIs. Review the full adverse medications list before starting any methylene blue protocol.

The FDA does not approve supplements before they are sold, so the checking is left to the company and to you. These five things take about a minute and work on any brand, including ours.

Look for: USP grade on the label. The amount in milligrams, or a percentage for liquid. A lab report you can open. A product sold by the brand itself. Powder that turns water deep blue.

If a product misses two or more of these, keep looking.

No grade, or aquarium grade. No amount stated anywhere. A lab logo with no report behind it. A seller you have never heard of, reselling another brand. Powder that stays white or brown in water.

Watch the claims too. A methylene blue supplement that promises to treat, cure, or prevent a disease is breaking the rules for supplements, and that tells you something about the rest of the label.

Anything that sounds too good to be true usually is.

Capsules hold a fixed amount, with no taste, no measuring, and no stains. Liquids let you measure very small amounts, but you have to measure carefully, and they stain skin, fabric, and countertops.

If you want simple and consistent, capsules. If you want fine control and do not mind the mess, liquid.

Either way, the grade and the lab report matter more than the form.

Store methylene blue in a cool, dry place, away from direct sunlight. Light can slowly break it down, which is one reason good brands use amber bottles.

Keep the lid closed, keep it away from children and pets, and keep the liquid away from anything you do not want stained.

If a liquid changes color or a capsule powder clumps or darkens, replace it.

The FDA does not approve supplements before they are sold, so the checking falls to the company and to you. A one-minute label check works on any brand, ours included.

• If a product misses two or more of the five checks, keep looking.
• Walk away from no grade, aquarium grade, or no stated amount.
• A lab logo with no report behind it does not count.
• Store it somewhere cool and dry, away from direct sunlight. Amber bottles help.
• Replace a liquid that changes color or capsule powder that clumps or darkens.