howtosupplement
Cognition

Methylene blue

Synthetic nootropic with weak human evidence for memory; historically used as a drug antidote and urinary antiseptic.

Methylene blue

Methylene blue

35
score
C
evidence
Caution
risk

Proven Benefits

01May improve memory and attention
02May prevent toxic encephalopathy

Chemical Forms

Recommended
  • Methylene blue (USP grade)
  • Methylthioninium chloride
Avoid
  • Industrial or laboratory dye grades (heavy metal contamination)
  • Aquarium or textile grades (unsafe impurities)
Expert Note

Only pharmaceutical USP-grade methylene blue has defined purity and safety standards for human consumption. Industrial and aquarium grades can contain heavy metals, zinc, and other contaminants at levels unsafe for ingestion. Oral bioavailability of standard methylene blue is already variable; unregulated grades add toxicity risk without proven benefit.

Protocol

Amount
0.5-2 mg
Frequency
Once daily, or only on high-demand cognitive days
When
Morning; avoid concurrent use with other serotonergic substances due to MAOI activity.

Safety & Limits

Upper Safe Limit
2 mg/day (no established UL; conservative ceiling based on nootropic trial doses)
Cycling
8 weeks on, 4 weeks off (chronic human safety data is absent)

Contraindications

G6PD deficiency — risk of hemolytic anemia
Pregnancy or breastfeeding — insufficient safety data
Severe renal impairment — reduced clearance
Current use of serotonergic antidepressants — risk of serotonin syndrome
History of methemoglobinemia or hemolytic disorders

Avoid Combining With

  • ✕SSRIs, SNRIs, or other serotonergics (serotonin syndrome risk — do not combine)
  • ✕Dapsone or other oxidant drugs (may increase methemoglobin risk)
Updated Invalid Date