l--carnitine Acetyl-L-Carnitine NutraBio® - L-Carnitine 3000 -
Description
The aforementioned information leads to the conclusion that sample and standard solutions are consistent up to 78 hours and 68 hours, respectively, when stored at room temperature

[DOI] [PMC free article] [PubMed] [Google Scholar] 108.Mendona LABM, dos Santos Ferreira R, de Cssia Avellaneda Guimares R, de Castro AP, Franco OL, Matias R, et al

As a result, most athletes will be better off using L-Carnitine Tartrate

Here's a little background info on it in case you're curious like me
