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Compounds › Neuro and cognition

Methylene blue

An 1876 dye that became a hospital drug

Partially approvedNeuro and cognition

Experimental material. Read before using anything from here.

Nothing on this page is a medical recommendation, prescription or treatment plan. It is an organized translation of protocols circulating in research communities and, where it exists, of what published trials tested. The two are marked differently — and they are not equivalent.

Most of the compounds here have no FDA approval for human use. Several are sold labeled "research use only", which means they have not gone through purity, sterility or dosage controls for human consumption. A community-reported dose is not a validated dose: it is what someone reported having done.

Talk to a licensed health professional before considering any of these compounds. If you already use one and feel anything unexpected, seek care — do not wait for the next routine test.

Specific caution for this compound: It interacts with serotonergic drugs (SSRIs, MAOIs) — risk of serotonin syndrome. It is the most important interaction on this entire list.

Summary

Synthetic blue dye that is also a medicine. It was created in 1876 as a textile dye and became one of the oldest drugs still in use. Chemical name: methylthioninium chloride. In hospital it is used to treat methemoglobinemia. Nootropic interest is at a much lower dose.

Quick reference

Format
Sold ready-made as an oral liquid. There is no powder to reconstitute.
Concentration first
Find the percentage on the label (0.5%, 1% or 2%) before counting any drops.
Low-dose window
Cognitive research showed a hormetic curve: low doses (~0.5–4 mg/kg) helped, high doses (>10 mg/kg) reversed the effect.
Grade
Pharmaceutical grade (USP) only. Industrial or aquarium dye may contain heavy metals.

Methylene Blue vs Methyl Blue vs Grades of Methylene Blue

Methylene Blue vs Methyl Blue vs Grades of Methylene Blue
TermWhat it isHuman use?
Methylene blue (USP)Pharmaceutical-grade methylthioninium chlorideYes — the only grade for people
Methyl blueA different dye (aniline blue family), not the same compoundNo
Industrial-grade methylene blueLower-purity dye for labs/manufacturingNo — contaminant risk
Aquarium methylene blueTreats fish; not made to human-purity standardsNo

Storage and handling

The rules below apply to practically every lyophilized peptide in this reference. Where a compound has its own requirement, it appears in the table in the previous section.

  • Lyophilized powder, sealed: refrigerator, between 2 and 8 °C, protected from light. Many tolerate room temperature for short transport periods, but that is tolerance, not a recommendation.
  • After reconstitution: always refrigerated, between 2 and 8 °C. The stability window drops to days or a few weeks, depending on the compound.
  • Never freeze after reconstituting. The freeze–thaw cycle degrades the peptide.
  • Do not shake. Swirl the vial slowly. Shaking breaks the peptide chain.
  • Bacteriostatic water down the wall of the vial, in a slow stream, not squirted directly onto the powder.
  • Cloudy solution, with particles or a color change: discard. There is no recovery.

Lab tests and monitoring

This list is the one that appears recurrently in the source, with small variations by compound. It serves as a starting point for a conversation with a professional — not as a substitute for that conversation.

  • Before starting: complete blood count, comprehensive metabolic panel, lipid panel, fasting glucose and HbA1c, TSH and free T4, blood pressure and resting heart rate.
  • Depending on the compound: IGF-1 (GH axis), lipase and amylase (VIP and the incretin agonists), serum copper and ceruloplasmin (GHK-Cu and blends containing it), CRP.
  • Reassessment: most protocols review between week 4 and week 8, and then every 8–12 weeks.
  • Do not wait for the routine lab test in the face of abdominal pain, visual changes, a change in a mole, shortness of breath, asymmetric swelling or any new and persistent symptom. That is a reason to seek care, not a spreadsheet item.

Evidence limits

What these numbers are and what they are not. The values above were preserved exactly as they appear in the source, without reinterpretation. What the source describes as community practice is marked as such in the tables; what came from a published trial is too. A dose repeated by many people does not become a validated dose by repetition.

Data source: peptidedosingprotocols.com, accessed on September 3, 2026. Translation and organization in Portuguese are original work. No primary source (PubMed, trial registry, package insert) was checked in building this page — the check was against the secondary source, and that alone.

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