One of the hallmarks of aging is a decline in energy metabolism in many tissues, especially liver, heart, and skeletal muscle
If metabolic markers (fasting glucose, HbA1c, insulin resistance) are improving at 5 or 7.5 mg, there may be no need to push higher
In some cases, further tests may be required to identify the underlying cause, such as the Schilling test (now rare) or the detection of antibodies against intrinsic factor or gastric parietal cells
The absence of pharmaceutical-grade quality control is not a technicality it means that even the identity, purity, and copper stoichiometry of a given vial cannot be assumed without independent verification
DSIP synthesis requires solid-phase peptide synthesis with nine amino-acid couplings