Methylene Blue

Methylene blue is a synthetic compound (thiazine/phenothiazine dye class) used for over a century as a textile dye.
also used as a medication to treat methemoglobinemia, cyanide poisoning, and malaria.
deep blue crystalline powder that dissolves in water to make a vivid blue solution.
it acts as a mitochondrial electron cyclist, enhancing energy metabolism and offering antioxidant, neuroprotective, and antidepressant effects.

ok so the FDA did approve methlyne blue as an emergency treatment for methemoglobinemia (a condition where your hemoglobin can't carry oxygen properly, causing blue-gray skin discoloration and oxygen deprivation).
can be caused by exposure to certain chemicals (nitrates, benzocaine, dapsone, some anesthetics) or by inherited genetic conditions.
given intravenously in the hospital at 1-2 mg/kg, effective within 30-60 minutes to restore normal hemoglobin function.

enhances mitochondrial ATP production in your brain cells. it makes it so that cells can make energy even when the machinery is dysfunctional.
low doses help but high doses actually hurt, so like... relax with it.
therapeutic dose is 0.5-4 mg/kg body weight per day (roughly 5-15 mg/day for a 150-200 lb adult). that's 1-3 drops of a standard 1% methylene blue solution.
good for age-related cognitive decline, chronic fatigue syndrome with mitochondrial dysfunction, post-COVID brain fog, mental fatigue, memory support, mitochondrial disease adjunct, and cognitive enhancement in healthy adults.

protects the brain from damage in stroke, traumatic brain injury, cardiac arrest recovery, and Parkinson's disease.
restores ATP production in oxygen-deprived brain tissue and reduces the damaging inflammation that spreads after brain injury.
also protects against mitochondrial toxins that cause parkinsonism (so if you've ever been exposed to acetogenins from annonaceae fruits, rotenone pesticides, or MPTP).

for Alzheimer's disease, methylene blue prevents tau-tau binding needed for aggregation, dissolves existing tau tangles, inhibits caspases (which contribute to neuronal death), reduces neuroinflammation.
so in other words, it binds to tau protein and prevents it from clumping together, plus dissolves existing tangles that have already formed.
use of methylene blue at 5-15 mg daily is common among integrative practitioners for early Alzheimer's, mild cognitive impairment, and dementia prevention.

do NOT use methylene blue if you're on any prescription antidepressant without medical supervision.
combining methylene blue with SSRIs, SNRIs, MAOIs, Tricyclic antidepressants like Elavil, Pamelor, others, and Tramadol (opioid pain medication), Meperidine/Demerol, Buspirone, St. John's Wort, 5-HTP, L-tryptophan supplement, triptans like Imitrex/sumatriptan, MDMA/ecstasy, and some cough suppressants (dextromethorphan/DXM).
all of which can cause serotonin syndrome when combined, and that can be fatal.
but yeah it does have antidepressant activity through the MAOI mechanism, especially at moderate doses. used clinically for depression and bipolar disorder.

works against modern chloroquine-resistant malaria strains. active against multiple Plasmodium species.
mostly relevant now for drug-resistant malaria in Africa and Southeast Asia.

used in hospital ICUs to treat septic shock, the type of dangerous low blood pressure that develops during severe infection when blood vessels dilate too much.
blocks the pathways that cause the vessels to dilate.
also used for hepatopulmonary syndrome (a complication of liver failure). specifically hospital use, not for outpatient sepsis prevention.
typical dose in septic shock: 2 mg/kg IV bolus followed by continuous infusion.

so there's some emerging cancer applications for mb, particularly in photodynamic therapy (using light to activate MB inside cancer cells to kill them) and as a surgical guidance dye for cancer removal.

can be used for urinary tract infections.
the compound is excreted through your kidneys and turns your urine blue-green while also killing the bacteria causing the UTI. oh and it's fda approved for UTI's, if you care about that. also used as topical antiseptic for wound care.

methylene blue can cause hemolytic anemia in people with glucose-6-phosphate dehydrogenase (G6PD) deficiency.

side effects are all temporary but include headache, dizziness, blue-stained urine/sweat/teeth/skin.

when applied to the skin or taken at low doses, makes skin cells live longer and stay healthier.
reduces the signs of aging in skin cells.
even in cells taken from people over 80 years old, the cells started behaving more like younger cells.
It helps skin produce more elastin (what keeps skin bouncy and firm) and collagen (what keeps skin thick and smooth).
also protects skin from UV damage from the sun, which is safer for coral reefs.
safe to use long term with no irritation even at high amounts on the skin.

FDA approved off-label for vasoplegic syndrome (the cardiovascular collapse seen in severe sepsis and after cardiac surgery).
methylene blues NOS inhibition and guanylate cyclase inhibition restores vascular tone when the body's own NO system has gone into overdrive.

compound crosses into breast milk. discontinue methylene blue if you want to breastfeed.

low dose (0.5-2 mg/kg/day): mitochondrial enhancement, antioxidant, cognitive benefit. THIS IS THE SWEET SPOT for cognitive and longevity use.
moderate dose (2-4 mg/kg/day): MAOI activity begins, serotonin increases, potential mood effects.
high dose (4-8 mg/kg/day): pro-oxidant effects emerge, benefits reverse.
very high dose (8+ mg/kg/day): cellular oxidation, methemoglobinemia risk in G6PD deficient individuals.