Methylene blue is a hashtag paradise on TikTok, where 5,500 #bluetongue videos were posted. Why? Ignoring the normal idiocy seen on the site there are all kinds of claims that it does wonders for [you name it].
When supplements are touted as being useful for a ridiculously large variety of unrelated medical conditions look out. This is as sure a sign of supplement BS as you'll ever see. Today's poster child is a fabric dye called methylene blue.
Here is an impressive list of unsubstantiated (some downright absurd) conditions claimed for the chemical, which was first synthesized in Germany 150 years ago.
I hate to break it to TikTok users but there is no drug in the universe that treats two dozen different conditions and it's a sure bet that methylene blue won't be the first, despite 155 Amazon products that make some of these claims.
→Treatment of methemoglobinemia
Time for a junk sale
Some sell it in style:
This stuff can put you in harmony with the Earth and make you wealthy!
Earth Harmony Methylene Blue Pharmaceutical Grade 99.99% with Dropper, with Liquid Gold (3) for Enhanced Photodynamic Activity & Increased Absorption, Methylene Blue USP Grade, No Formaldehyde (2 Oz)Liquid
Actiblue+ Methylene Blue 1% : Methylene Blue Pharmaceutical Grade ISO Certified Third Party Lab Tested 99,9% No Formaldehyde No Alcohol No Gluten & GMO (2Fl.Oz)
Homo sapiens moronicus on TikTok
Steve (left) and Irving, both avid TikTok fans, tried the stuff. It didn't work. It remains to be seen whether they can become influencers.
The name is apt.
(Left) Pure methylene blue is so blue that it appears black in solid form. (Center) A dilute solution is so dark that it looks like paint. How dilute? The flask contains 10 mg dissolved in 200 mL of water – a paltry 0.000157 M. To give this some perspective, if you make a salt solution of the same concentration it would take 1.8 mg of salt dissolved in 200 mL. The threshold for the human taste of salt is about 60 times higher, so you wouldn't even know the salt was there. Not even close.
But if you hold the flask in front of a powerful light source, perhaps a supernova, you can see through it – one of the requirements of a solution. On the right is a serial dilution experiment. The third tube contains 0.0001 grams (0.1 mg) of methylene blue dissolved in 100 mL of water (0.00000313 M) but you can still see the color. Credits: Sigma-Aldrich catalog, Wikipedia, Flickr
Methylene blue makes these guys jealous. Image: Wikimedia
Snotty comment time!
Of course, according to homeopathic principles, the color should get darker the more you dilute it, right? Makes as much sense as the rest of it.
Methylene blue is used to treat methemoglobinemia. The chemistry is very cool. And very simple.
Methemoglobinemia is a dangerous (thankfully rare) condition in which an elevated level of methemoglobin, an oxidized form of hemoglobin, is present. Methemoglobin cannot carry oxygen effectively, leading to reduced oxygen levels throughout the body. It is caused by the oxidation of hemoglobin (see below) by certain drugs and chemicals (acquired methemoglobinemia) or genetic mutations (congenital methemoglobinemia). When it happens, the antidote is methylene blue. Here's the reaction. First, let's simplify things (Figure 1).
Figure 1. Hemoglobin (functional) and methemoglobin (non-functional) are identical except for the oxidation state of the iron. Iron II binds to oxygen while iron III does not.
We can (overly) simplify things in the form of a redox reaction, one of the fundamental chemical reactions in chemistry and biochemistry.
Fe+3 (non-functional) + methylene blue ----> Fe +2 (functional)
Of course, it's not that simple. There are a few details required.
Step 1: Methylene blue is reduced by NADPH to give a reduced form of the molecule called leucomethylene blue, the reduced form.
STEP 2: Leucomethylene blue, now a reducing agent (donates electrons) does just this to methemoglobin, reducing the Fe+3 back to Fe+2, which converts methemoglobin back to hemoglobin.
Chemistry lesson over! Hopefully, you didn't turn blue while reading it.
Reasons not to use methylene blue
A therapeutic dose of methylene blue is typically 1-2 mg IV. A toxic dose is about 7 mg. This is a very low therapeutic index, which makes drugs more dangerous. In a case of mind-boggling irony, one of the symptoms of methylene blue toxicity is methemoglobinemia (!). Other toxic manifestations of methylene blue poisoning include GI symptoms, respiratory problems, dangerous interactions with SSRI antidepressants, and seizures, to name a few. In extreme cases, anaphylactic shock is possible.
Here's an example of the potential dangers of the supplement. Amazon sells multiple brands of the stuff. I chose one randomly.
This product contains a 1% solution of the drug. Each bottle contains 50 mL (about 1000 drops). Each drop contains 0.5 mg; 14 drops (1-fiftieth of an ounce) will contain about 7 mg – the estimated toxic dose in adults (and it's much lower in children). So, a single bottle contains 500 mg of methylene blue, roughly 70 times the toxic dose in adults and possibly a lethal dose in children. So if a child were to drink a bottle of a 1% solution – less than 2 ounces – he or she would become very ill and possibly die. (A 1% solution is described as "mildly bitter"). And ironically, although methylene blue is an antidote for methemoglobinemia there is no antidote for methylene blue poisoning. I have not even explored the sometimes enormous difference between what has been claimed on the bottle and the amount that is actually there when found in subsequent testing, a topic I have written about frequently.
Bottom line
Unless you have methemoglobinemia (in which case you'd better be near a hospital) you'd have to be out of your mind to take this stuff (personal opinion). And if you want, perhaps to make the 5,501st TikTok video, a blue tongue there are safer alternatives. Here's one.
NOTES:
(2) Gold melts at 1,947oF. This is quite unlikely to be in the bottle.
Josh Bloom
Director of Chemical and Pharmaceutical Science
Dr. Josh Bloom, the Director of Chemical and Pharmaceutical Science, comes from the world of drug discovery, where he did research for more than 20 years. He holds a Ph.D. in chemistry.
