acetyl-l-carnitine neuropathic pain meta-analysis 2019 randomized Frontiers Acetyl-L-carnitine in painful peripheral neuropathy:

During the course of a pregnancy, the growing fetus has substantial nutritional and energy needs, especially in the later trimesters, and the body also prepares for even greater energy demands in the future (Castillo-Matamoros & Poveda, 2021)

During sustained oxygen deficiency, extracellular adenosine levels rise sharply

While these findings provide valuable insights, we acknowledge that further research is needed to delve into the specific molecular mechanisms at play in this context

However, "unlike most other vitamins, B12 is stored in substantial amounts, mainly in the liver, until it is needed by the body," according to Merck Manuals Consumer Version