Interesting Facts About L-Carnitine that No One Talks About

So here, let's go about carnitine in some non-energy-producing systematic effects. So what do we mean by all that? Hey, it's Dr. A. On this channel, we talk about all things integrative medicine. And so if you're interested in that sort of thing, consider subscribing to the channel and join us. Carnitine, as we've talked about in other content on this channel, is primarily known as an energy helper. So its job inside of the cell is to help fats go side of the mitochondria. They can be beta-oxidized for energy substrate and help us make ATP. It's a short version. We have longer videos on that. And so most people think of carnitine, rightly so, as something that we might use during energy deficits and crisis, recovering from a chronic illness, recovering from surgery. All of those are legitimate uses and things to consider. But carnitine also has a much lesser-known role in the body that's much more global beyond energy, and that is in the regulation of the hormone system or the endocrine system. And so as you probably realize, there's many, many hormones. We have all our reproductive hormones, we have our adrenal hormones, we have thyroid hormones, hormones related to satiety and eating, hormones related to blood sugar control, all those things, right? And many, many more hormones go on and on forever. And the endocrine system or the hormonal system comes from all over the body. We literally make some type of hormone or another in just about every location in the body. And so there's a lot of counter-regulation. One of the things is that hormones have crosstalk. So for example, if I alter my cortisol levels, I may alter my insulin. If I alter my insulin or my glucagon, I may have an effect on my adrenaline or epinephrine family of neurohormones. So there's all that sort of crosstalk that goes on. And then kind of the ghost in the machine on the outside is what we call counter-regulation. And really where carnitine plays a role. Now, the first thing is that there is a thing in the body called the carnitine pool. And so this means that in, especially in liver cells where we have the amino acid pool, we'll have carnitine there, but also there'll be extrahepatic or outside the liver sites for carnitine because we use it in all of our cells, as we said, for energy production. But in addition to energy production, the level of carnitine that is available helps to regulate the secretion and metabolic behavior of different hormones. And it certainly doesn't affect every hormone, but affects a lot of your real important hormones. So I thought I'd just talk about which hormones it's, it's most known for. There's many others, but we'll go through kind of the big ones you probably heard about. The first one is that carnitine actually influences insulin sensitivity. Insulin sensitivity is one of those things that in a non-diabetic person is considered abnormal, meaning that the receptors that insulin binds to, to open the receptor up and let glucose in, are maximally sensitive to the insulin binding. Insulin insensitivity is when the insulin comes out and doesn't bind well to the receptor. The receptor is turned down, so its sensitivity is low. What happens then is usually the body through the pancreas will make more insulin to try and overwhelm the receptor and have it open up so that we get sugar in. Insulin insensitivity is common in type 2 diabetes. For example, and pre-diabetic people often have growing insulin insensitivity. So one of the things, although it's not primarily thought about in helping with metabolic problems and insulin sensitivity, is the use of carnitine as a supplement and looking at carnitine in your diet to help make sure that the carnitine pool is so-called full so that we have enough carnitine to help the insulin sensitivity. Now, is that the only thing that changes insulin sensitivity? No, but it's something that most people don't realize is a factor in insulin sensitivity. The other one, which is a little more common because it's a caution with supplementation that people often are given, is that carnitine is a thyroid hormone regulator. So what happens is when carnitine builds up, if it's at a regular level, the conversion of thyroid hormone from inactive to active forms will be at about A normal level. If we take too much carnitine and we overdose the system, the thyroid can have feedback where the carnitine pool gets too big and the conversion through the nuclear transfer, they call it, will slow down. And so our thyroid production will slow down. Now, just for sake of reference, this does not happen in one day. So if a person is supplementing, and I'll use L-carnitine as an example because the units are different with acetyl-L-carnitine as far as doses we use, But let's say you have a patient who is coming off of a protracted illness. They have fatigue and everything, and you're trying to replete their carnitine. You might be having that person take 2,000 to 4,000 milligrams of carnitine a day to replete their system. Generally speaking, and the research is a little, you know, all over the map on this, but generally speaking, in an adult human, in order to slow the thyroid down, you have to get over 3,000 milligrams for quite a while. So what does that mean? Well, If you're taking it to recover from an illness or help your fat metabolism or some other thing, you can probably take 3,000 or 4,000 milligrams for 2 months and never affect your thyroid function. If you start taking above 3,000 or 4,000 milligrams and you do it longer than say, you know, 2, 3 months, you're probably going to start to have a downward effect on your thyroid output. So that's one where it's a regulator, but if we have too much, it can be a negative regulator. The other one that's not as well known is through the Balancing and regulation of the glucocorticoids, which come from the adrenal glands. So on the outside of the adrenal glands are made in 2 parts embryologically. The middle part is a neurological tissue. The outer part is the endocrine tissue, and they call the outer part the cortex. So cortisol, cortisone from the cortex. Glucocorticoids are mostly the cortisol family, and there's some relatives. Well, it turns out that through genetic regulation, the carnitine pool helps to maintain glucocorticoid feedback and actual regulation and production genetically. If we get too low in carnitine, it's one of the many, many reasons glucocorticoid output can become abnormally shifted. The next thing is through feedback mechanisms in our metabolic regulatory hormone system. So in your brain, you have a place called the diencephalon, and then part of that's called the hypothalamus, and that connects down to To the pituitary and there's release of hormones, et cetera. Well, there's a metabolic group of hormones that are there for balance and use of different food substrates, let's say. So the one you know most about, we already talked about, was insulin. Well, it turns out carnitine through the central nervous system is involved in insulin triggering. So the pro-hormones that go out from the central nervous system to help balance insulin release come, you know, partly because of carnitine pool balance. But then the release of 2 hormones that are trying to balance each other out, but sometimes get out of balance being ghrelin with a G and leptin. You may have heard of these. The balance of ghrelin and leptin have a lot to do with your natural ability to have satiety. So you eat and then you're not hungry. Some people will always be hungry. They will eat and they'll be hungry very quickly. Other people will almost never be hungry. And so they kind of have to force themselves to eat. And the balance ghrelin and leptin 2 hormones that feed back to the brain to say, okay, we've had enough to eat, or, oh, we need to eat some more. And the more out of balance they are, the more likely you are to tip one direction or the other, either not really having a desire to eat or having a desire to eat all the time. And obviously the balance would be somewhere in the middle where when I need to eat, I get signals that it's time to eat. But when I am full, I don't have signals that I need to eat anymore. Well, turns out that that the carnitine pool is incredibly important in the balance of ghrelin and leptin, which is more fairly new type of discovery. I want to mention a particular paper if you want to look it up and you're into, you know, really deep looks into things on carnitine. It's Dr. Zhang et al., X-I-A-N-G, first initial F, and this is in the Journal of Translational Medicine, 2005. And if you just put in your search bar X-I-A-N-G comma F and then Journal Translational Medicine and then Comprehensive Review of the Expanding Roles of the Carnitine Pool dot dot dot, you'll find that paper. It's a very interesting paper. It was just published in 2025, so this year that I'm recording this. And again, if you're really into that sort of thing, I think you'll find it of interest. All right, thank you guys for listening. Thank you all the subscribers. Please do consider subscribing if you haven't. Like and share, and I will see you all on the next video.