If you have ever been into a GNC or similar supplement store you have probably been subjected to a maze of products with a ton of science sounding words on it that don't mean anything to you. L-carnitine is probably one of those things that you may have encountered and it is just another gimmicky big word that is made up to make you think that it has some sort of magical properties that can boost this and boost that but the fact of the matter is that L-carnitine, just like most of the other big made up words that come on these supplements, doesn't actually do anything at all.
Usually, just like with most other bogus products they have an aggressive and mostly empty gigantic plastic bottle with aggressive fonts and mean sounding names to make stupid people think that this product is actually going to help them.
L-carnitine is sold under a number of names but the underlying claim is always the same and that is that using this product will "increase fat burn." Like I have said many times in the past, there is no such thing as a product in existence that isn't poisonous or involving invasive surgery that is capable of "fat burn."
The only way to burn fat is to create a caloric deficit in your body by way of diet and exercise. Then, your body gets to work on your fat supplies first but only if you regularly exercise. If someone out there is thinking that they can just take L-Carnitine shakes or tablets and starve themselves and watch the fat fall off of them, they are horribly misguided since your body will normally "consume" atrophied muscle first before it touches the fat. I am not going to pretend to know why, I just know that this is the case.
Then there is also the fact that the stuff that these supplements are meant to provide to your body are actually produced by your body at precisely the level your body needs it if you just eat a normal diet. Therefore, any excess that you consume in the form of supplements simply gets processed by the kidneys and liver and passed through as urine anyway. You are literally pissing your money away if you get involved with this bogus supplement.
The containers will present these outrageous graphs about extra fat loss but real studies conducted by actual scientists come to very different conclusions. When people are given L-carnitine supplements and a controlled diet, they experience weight loss as is shown in this peer-reviewed study .... so that means it works right? Well, not really. Even the author of this study admits that the sample size was too small to come to conclusive results. In fact, there is no scientific study that can conclude that L-carnitine has any impact on weight loss at all and the only time that anyone can find any reason to take this product at all is in the case of vegetarians or vegans who don't get "enough" natural protein in their diets.
So if you are a vegan and struggle to get enough protein, you are better off just taking a protein supplement because it will have the same result as taking this and just happens to be one of the only supplements I actually agree with (and has science to back it up.)
It reminds me of a guy that I knew in high school that when he would feel a cold coming on would take a product called I think it was "Emergen-C" and it was an orange tasting powder that had something crazy like 4000% the amount of vitamin C that your body needs in a day. That product, much like L-carnitine is basically like over-filling the gas tank of your car and dumping an extra 40 gallons on the ground next to your car and then assuming that your car is somehow going to be able to use it to get you further down the road.
The facts here are that no study on L-carnitine has been able to produce any sort of significant results on animals at all, let alone humans and this is just another overly expensive product that you do not need.