Methylene blue: an emergency IV drug sold as a daily supplement
Methylene blue has eight approved applications in Drugs@FDA and every single one of them is an intravenous solution for acquired methemoglobinemia, a condition treated in a hospital. Nothing is approved to be swallowed, and nothing is approved for energy, focus or aging. The label of the branded product goes further and tells you not to inject it under the skin.
What this comes down to
- All eight approved methylene blue applications are intravenous solutions. The indication on every one is acquired methemoglobinemia.
- The label carries a serotonin syndrome warning for use alongside SSRIs, SNRIs and MAOIs, and says some reported cases were fatal.
- It's contraindicated in G6PD deficiency because of the risk of hemolytic anemia, which is an inherited condition a blood test finds and nothing else does.
- One 37-person crossover trial in bipolar disorder used 195 mg a day against a 15 mg comparator. It improved depression scores and found no significant effect on cognition.
What is approved, and in what form
Query Drugs@FDA by active ingredient and methylene blue returns eight applications: the branded ProvayBlue, approved April 8, 2016, and seven generics approved between 2023 and 2025[1]. Every one is a solution for intravenous use. There's no approved tablet, no approved troche, no approved drop.
The indication is one line long: treatment of pediatric and adult patients with acquired methemoglobinemia[2]. That's a condition where hemoglobin stops carrying oxygen properly, usually after exposure to a drug or chemical. It's treated in a hospital, at 1 mg per kilogram, over five to thirty minutes.
“Do not administer PROVAYBLUE subcutaneously,” the prescribing information says, in a section otherwise about how to get a line in. Some sellers offer methylene blue as an injectable. That instruction is worth reading before you buy one.
The interaction that matters most on a weight-loss platform
Methylene blue is a monoamine oxidase inhibitor. Its label carries a warning for serotonin syndrome when it is used alongside serotonergic drugs, naming SSRIs, SNRIs and MAOIs, and adding that opioids and dextromethorphan raise the risk too[2]. The label says some of the reported cases were fatal.
That matters here more than it would on a general supplement site. An intake built around your weight history doesn't necessarily reconcile a full medication list. If you take an SSRI or an SNRI, this is the question to raise before anything else.
The label contraindicates methylene blue in glucose-6-phosphate dehydrogenase deficiency, because of the risk of hemolytic anemia. G6PD deficiency is inherited, and a blood test is the only thing that finds it. Worth knowing whether you have had one.
What the human trials actually tested
There's a real literature here, and it's mostly about surgery, poisoning and vasoplegia rather than about longevity or focus. Filtered to randomized trials in humans, PubMed returns 383 papers. Narrow the same filter to cognition, memory or Alzheimer's and it returns eight.
PubMed, via the E-utilities API
"methylene blue"[tiab] AND (longevity[tiab] OR "anti-aging"[tiab] OR fatigue[tiab] OR "mitochondrial function"[tiab]) AND "randomized controlled trial"[pt] AND "humans"[mh]
Returned 2. Positive control — methylene blue, same filter, no topic restriction — returned 383 through the identical filter in the same session.
The control is the same drug through the same filter, which is what makes the two a real comparison rather than a rhetorical one. The filter finds 383 randomized trials of methylene blue and two that touch longevity, anti-aging, fatigue or mitochondrial function.
The trial that gets cited most often for mood is a six-month crossover in 37 people with bipolar disorder already taking lamotrigine. It compared 195 mg a day against a 15 mg dose used as the comparator, and found improvements in depression and anxiety scores[3]. The effects on cognition were not significant, which is the claim most often made for it.
The control arm got 15 mg of methylene blue, not a placebo. Thirty-seven people, one diagnosis, one background medication, and an active dose roughly double what a wellness seller suggests. It's a reason to run more trials, not a reason to take it daily.
Where a compounded version stands
Methylene blue is the active ingredient of approved drug products, so a 503A compounder has a lawful route to the bulk substance — the second of the three conditions[4]. It doesn't appear anywhere on the FDA's page of substances flagged as presenting significant safety risks in compounding[5]. Neither of those facts makes an oral preparation equivalent to the approved IV one, and compounded drugs aren't FDA-reviewed for safety, effectiveness or quality before they're sold[6].
The FDA category-2 compounding page, full text read the same day
full-text search of the page for "methylene"
Returned 0. Positive control — ipamorelin, same page, same read — returned 6 through the identical filter in the same session.
Reported as a point in the substance's favor. The absence is only meaningful because a term that is on the page was searched in the same read and found.
What it costs where we have found it
Methylene blue shows up on one of the 101 sellers we have priced, at $89 a month. WePeptideRx sells it beside a peptide menu rather than as a standalone product, which is how it usually appears. Our read of any seller is about what it publishes and charges, not about whether a molecule works, and the method is on how we grade.
Questions people actually ask
Is methylene blue FDA approved?
As an intravenous solution for acquired methemoglobinemia, yes — eight applications carry that approval. As an oral product for energy, focus, mood or aging, no. There's no approved oral methylene blue product of any kind in Drugs@FDA.
Can you take methylene blue with an antidepressant?
The approved label warns against it. Methylene blue inhibits monoamine oxidase, and combining it with SSRIs, SNRIs or MAOIs has produced serotonin syndrome, including cases the label describes as fatal. Anyone on a serotonergic medication should raise this with a prescriber before starting.
Who should not take methylene blue at all?
The label contraindicates it in people with glucose-6-phosphate dehydrogenase deficiency, because of the risk of hemolytic anemia, and in anyone with a severe hypersensitivity reaction to methylene blue or another thiazine dye.
Does methylene blue improve memory or focus?
Eight randomized trials in humans touch cognition or memory, against 383 randomized trials of methylene blue overall through the same filter. The most cited of them, a six-month crossover in 37 people with bipolar disorder, found no significant effect on cognition.
Sources
Every source here was fetched and read for this article, with the identifier taken off the record that came back and the claim it supports written down beside it. All of it was read in September 2026, the same session the rest of this page draws on.
- Drugs@FDA: FDA-Approved Drugs, queried through the openFDA API. U.S. Food and Drug Administration, 2026. Source · Methylene blue as an active ingredient resolves to eight applications, all solutions for intravenous use. ProvayBlue is NDA 204630, approved April 8, 2016; the remaining seven are generics approved between December 2023 and December 2025. A deliberately fake ingredient name returned an empty result on the same endpoint in the same session.
- PROVAYBLUE (methylene blue) injection — FDA prescribing information. U.S. Food and Drug Administration, Structured Product Labeling, 2025. Source · Document dated May 2025The single indication, acquired methemoglobinemia; the 1 mg/kg intravenous dose; the instruction not to administer subcutaneously; the serotonin syndrome warning naming SSRIs, SNRIs and MAOIs and stating that some reported cases were fatal; and the contraindications in G6PD deficiency and thiazine dye hypersensitivity.
- Methylene blue treatment for residual symptoms of bipolar disorder: randomised crossover study. The British Journal of Psychiatry, 2017. PMID 27284082 · doi:10.1192/bjp.bp.115.173930 · Thirty-seven participants, six months, an active dose of 195 mg against a 15 mg comparator in patients already taking lamotrigine; depression and anxiety scores improved, and the effects on cognitive symptoms were not significant.
- Bulk Drug Substances Used in Compounding Under Section 503A of the FD&C Act. U.S. Food and Drug Administration, 2026. Source · Document dated May 2026The three conditions a bulk substance must meet under section 503A, of which methylene blue meets the second: it is a component of FDA-approved drug products.
- Substances in Compounding that May Present Significant Safety Risks. U.S. Food and Drug Administration, 2026. Source · Document dated April 2026Methylene blue appears nowhere on the category-2 page, on either table, while ipamorelin appears six times on the same read.
- Compounding and the FDA: Questions and Answers. U.S. Food and Drug Administration, 2025. Source · Document dated September 2025Compounded drugs are not FDA approved, meaning the agency does not verify their safety, effectiveness or quality before they are marketed.