Description: A Polyaromatic Stain
Dosage: between 0.5-4.0 mg/kg, or microdosing from 60 mcg
CAS Number: 61-73-4
Storage Instructions: Room temperature
What is Methylene Blue?
In a clinical setting, methylene blue (methylthioninium chloride) is used as a polyaromatic stain, and also as a medication for treating disorders like methemoglobinema.
Here is the Methylene Blue structure:
Methylene Blue Uses
In more recent years Methylene blue has also been studied for its cognitive and mitochondrial-enhancing properties. Some have suggested Methylene Blue for hypotension, however, the research has not yet extrapolated from rodents to human conditions.
Methylene Blue Supplement
Methylene blue is listed as one of the most effective and safe medicines needed in a health system in the World Health Organization’s List of Essential Medicines. 
Methylene blue is a potent monoamine oxidase inhibitor (MAOI).  MAOIs were the first class of antidepressants; enzyme monoamine oxidase is involved in removing neurotransmitters dopamine, serotonin and norepinephrine. MAOIs prevent this from happening.
MB is one of the most effective agents in delaying senscence (aging) in human cells. Being a mitochondrial-targeting antioixidant, MB is able to stimulate skin fibroblast proliferation, promote wound healing, and upregulate elastin and collagen 2A1. 
MB also enhances mitochondrial function by increasing heme synthesis, cytochrome c oxidase, and mitochondrial respiration (achieved at nM concentrations), all of which help cognition. 
Methylene blue may slow down the progression of Alzheimer’s disease by inhibiting the cGMP pathway in addition to reducing the formation of amyloid plaques, while repairing some of the impairments in mitochondrial function and cellular metabolism.
Methylene Blue Nootropic
Low doses of methylene blue act as a neuroprotective agent, supports memory consolidation, and prevent various neurochemical, structural, and functional deficits derived from mitochondrial inhibition and oxidative stress. 
In a randomized, double-blinded, placebo-controlled clinical trial, low-dose methylene blue was proven to increase functional MR imaging activity during sustained attention and short-term memory tasks while enhancing memory retrieval. 
Large doses of MB can promote oxidative stress, so the traditional recommended dosages are between 0.5-4 mg/kg. This is for some desired effects such as MAOI inhibition. Many want to know how much methylene blue should be used in order to improve cognition. In this case, it is generally better to microdose, starting at around 60 micrograms.
The side effects of methylene blue are generally dose-dependent any methylene blue toxicity are minimal at low-doses (0.5-4.0 mg/kg) in humans. 
Because methylene blue is a monoamine oxidase inhibitor (MAOI), taking MB at large doses while taking SSRIs or other serotonin reuptake inhibitors could cause serotonin toxicity. 
As a precaution, when taking MB it is recommended to stick to lower doses (under 5mg/kg) while stopping any SRIs, especially paroxetine and fluoxtene and other potent cytochrome P450 2D6 inhibitors. A list of strong inhibitors (including fluoxtene, paroxetine, bupropion, quinidine and others) can be found here. [9,10]
Where to buy methylene blue
Methylene Blue Solution
This methylene blue has been backed by analytical methods and prepared as a solution using deionized water. This vendor has taken the time to create a Methylene Blue solution preparation which makes it easy to apply in vitro as part of a Methylene Blue stain or injection.
Methylene Blue Powder
Or, if you prefer to make your own solution, you can find methylene blue pharmceutical grade powder here.