In this video, the presenter reviews a recent study titled “The regulation of mammalian cellular metabolism by endogenous cyanide production.” The research shows that low concentrations of cyanide are naturally present in mammalian tissues—especially the liver—and that the body can increase cyanide production when supplied with the amino acid glycine. Within lysosomes, glycine is chemically converted to cyanide, which then diffuses out and acts as a signaling molecule. At these signaling‑level doses, cyanide enhances mitochondrial bioenergetics, boosts overall cellular metabolism, and protects cells from injury, as demonstrated in mouse heart‑attack models. Human blood cyanide levels are similar to those in mice (~500 nM). The video emphasizes that while cyanide itself is a deadly toxin at high doses, the endogenous, low‑dose signaling role is beneficial, and direct cyanide supplementation is dangerous. Instead, glycine—available as an over‑the‑counter supplement and found in many foods—can safely raise endogenous cyanide to therapeutic levels. Human studies have used 5–10 g of glycine per day with positive metabolic effects. The presenter cautions viewers not to misinterpret the findings as a recommendation to ingest cyanide, framing the discovery as a striking example of how “villain” molecules can have essential physiological functions.
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This paper blew my mind. What if I told you that cyanide, one of the most infamous poisons in history, might actually be keeping you alive? Your body makes it. Your metabolism might even need it. And science is only just uncovering its surprising benefits. I did say benefits. But do not get any ideas. I'm not saying cyanide is your next dietary supplement. Let's dive into the data before someone misinterprets this and starts bottling organic cyanide on Etsy. Quickly, what is cyanide anyway? Cyanide derives from the Greek cyanos, meaning dark blue, and it consists of a carbon atom triple bonded to a nitrogen atom. Cyanide is infamous for its lethal potential, but today In this video, it's getting a PR makeover. Think of it like a villain redemption arc. Like Loki, if you know the Marvel Cinematic Universe. Anyway, cyanide is found in deadly hydrogen cyanide gas and can also be produced by certain plants as defense chemicals, as in the pits of apricots or raw cassava. Cyanide kills by blocking Complex IV in mitochondria, effectively choking the energy-producing factory of the cell. The result? Death. But as with many things in biology, the dose makes the poison. And in this case, new research shows that cyanide is actually an important signaling molecule that boosts metabolism at low doses. The paper in question is entitled "The regulation of mammalian cellular metabolism by endogenous cyanide production." And the researchers find—spoiler alert—that low concentrations of cyanide are generated endogenously, meaning by the body, in various mammalian tissues, and that cyanide exerts stimulatory effects on mitochondrial bioenergetics, meaning it boosts energy metabolism, as we will show later in this video, and that low-dose cyanide supplementation—yes, I did say that—exhibits cytoprotective, meaning cell-protective, effects. Again, do not overdose on cyanide because of this video. Give me a chance to unpack these data. Stick around till the end. This is an important one. You don't want to misunderstand it. Okay. The first step in this research was to confirm that mammals' tissues actually contain cyanide naturally. So to do this, the researchers blended up different tissues and organs and measured cyanide levels. And they indeed found cyanide throughout the body with the highest levels being in the liver. And I know there are two colored bars here. I'll explain the difference in a moment. But first, let me acknowledge these organs are from mice. I don't know if the researchers asked their ethics board to approve the harvest of living human brains and livers, but if that request did get approved, I'm guessing they would have a hard time finding volunteers. I mean, I know a lot of people who would do a lot for a $100 Starbucks gift card, but donating their brains probably isn't on the list. That said, the researchers also documented that cyanide levels in the blood of healthy mice and healthy humans are actually very similar, at a concentration of around 500 nanomolars. Now, what about these blue bars? Here's where things get really interesting, and probably a bit more practical for you too. A major finding of this research was that cyanide production by the body can be stimulated by the simple amino acid glycine. And the blue bars represent glycine treatment. And as you can also see here, microscope images of human liver cells treated with glycine, where red represents more cyanide, there's clearly more cyanide when the glycine is present. So, high-level glycine makes your body produce more cyanide. It's kind of like finding out eating olives makes your body generate tiny shots of espresso, which for the record I would not complain about. I love olives and coffee. Anyway, now I'm going to spare you some of the finer details on the experiments and technicalities of the methods that the researchers conducted to determine the mechanisms at play whereby glycine increases cyanide production, and instead provide you with the high-level biological summary, which was nicely complemented by a very nice figure in the paper shown here. Okay, in the acidic compartment of the cell called the lysosome, the amino acid glycine can be converted into cyanide, and then the cyanide can diffuse out of this lysosome compartment. It's kind of like a ghost passing through a wall. And it then acts as a signaling molecule. The cyanide is a signaling molecule that can boost mitochondrial metabolism, itself attach to and alter the function of a buffet of proteins. The cyanide literally attaches to other proteins and toggles their function. And it can even protect cells from injury and maybe death. So to summarize, glycine supplementation causes an increase in the body's own production of low-dose cyanide, which then acts as a signaling molecule with several beneficial metabolic effects. How crazy is that? And as a remarkable case in point, treatment with glycine increased mitochondrial metabolism, as shown here. But this effect was erased when cells were treated with molecules that gobble up cyanide, which you can see in the pink and the dark blue bars. And what this suggests is that glycine is boosting metabolism by increasing cyanide signaling. And in terms of the protective effects, this is really cool. What you're looking at here is basically injury from a mouse heart attack, where blue indicates more dead tissue in the mice heart. Treatment with glycine or a compound that increases cyanide production called amygdalin. This is one of the compounds actually found in raw cassava, apple seeds, and apricot pits. Anyway, increasing cyanide production or supplementing with glycine, which also increases cyanide production, protected against the death of cells and tissues, providing proof of principle for therapeutic applications of this remarkable new science. And as relates to you, I'll do like cyanide's triple bonds and say for a third time, do not supplement cyanide. Because just like a cyanide molecule, this message is held together by a triple bond of seriousness. I do not want you to die. However, glycine, which may trigger your body to generate cyanide at safe signaling levels, is an over-the-counter supplement and a simple amino acid found in many protein-containing foods. And other literature actually shows that glycine levels drop in aging and in certain metabolic diseases like obesity and diabetes. And at least in preclinical models, animal models, glycine supplementation does improve mitochondrial energy metabolism and muscle health. Consistent with these new data. And because I know I'll get asked the question about dose, a ballpark of 5 to 10 grams has been explored in human studies with glycine, with some positive effects, perhaps owing to cyanide production in the body, as revealed by these new data. Anyway, finishing up, science has a way of flipping everything we knew on its head. Cyanide is not just a poison but a key player in your metabolism. What's next, arsenic as a vitamin? Okay, maybe not. But it does make you wonder—what else don't we know about the chemicals inside our bodies? Drop a comment—does this discovery blow your mind? I know it did mine. And if you found this as wild as I did, hit like, subscribe, and share this video with someone who loves uncovering the weird secrets of the human body. Stay curious, and thank you, and don't drink cyanide. I am inevitable.
