What the research shows
In a double-blind study, 14 healthy men received carbohydrate with or without L-carnitine L-tartrate. The researchers sampled muscle tissue during a 24-week cycling study. Muscle carnitine rose 21% from baseline in the carnitine group and stayed similar in the comparison group. Both groups received carbohydrate, and the small study measured exercise metabolism in these volunteers. See the muscle sampling and cycling trial.
Documented formats
The study identifies L-carnitine L-tartrate as the test material. When comparing sources, record whether the listed amount is the mass of that salt or the amount of L-carnitine it provides.
Testing and purity
The L identifies a specific three-dimensional arrangement. A useful identity test distinguishes it from D-carnitine, which has the same mass but a different arrangement.
How to read a batch reportQuestions about L-Carnitine
Why did the researchers take muscle biopsies?
Blood and muscle are different compartments. Sampling tissue allowed them to measure how much carnitine had accumulated in muscle itself.
Can I use these results to interpret an acetyl-L-carnitine study?
Record that as a different compound. It has an additional acetyl group, and the cycling study specifically tested the tartrate salt.