The 500 Dalton rule (molecular weight below 500 Da correlates with percutaneous absorption) is a necessary but not sufficient condition, not a guarantee
(Frontiers in Pharmacology, 2022) reports a half-life under 30 minutes after IM or IV administration in rodent and dog models, which is why split-dose schedules appear in the literature
Modre-Osprian R, Osprian I, Tilg B, Schreier G, Weinberger KM, Graber A (2009) Dynamic simulations on the mitochondrial fatty acid beta-oxidation network
When youre losing weight, you can use sequential DEXA scans to ensure that most of the weight youre losing is fat
The body makes collagen from key vitamins, minerals, and several processes