Dynamic cycling of membrane phospholipids Glycerophosphocholine (GPC), phosphocholine (PC), and (to a lesser extent) free choline are the primary sources of the tCho signal [13]
However, smaller nanoparticles are prone to agglomeration and rapid excretion through the kidneys, evading liver uptake and reducing the circulation time in the body, ultimately diminishing the therapeutic efficacy [20]
Sutton R, Mason SA, Stanek SK et al (2016) Microplastic contamination in the San Francisco Bay, California, USA
Otherwise, they can be contaminated with toxins or other factors that are quite dangerous. Kennedy has publicly argued that making peptides available at compounding pharmacies again would make them safer, because these facilities are subject to some regulation (although nothing as stringent as the regulations regarding true FDA-approved drugs)