It contains 0.9% (9 mg/mL) benzyl alcohol, which functions as a bacteriostatic preservative by inhibiting microbial growth in the vial
Most researchers report first noticing skin texture improvements around week six to eight
Because of these factors, laws worldwide define which drugs are prescription only. For example, in the United States the Food and Drug Administration (FDA) designates drugs as Rx only (meaning prescription required) if they are not safe for self-medication
The first cardiovascular study of NNMT enzyme inhibition in a heart failure with preserved ejection fraction (HFpEF) mouse model demonstrated that treatment markedly reduced 1-MNA (by 77.1%), 2PY (by 66.2%), and 4PY (by 71.1%) in cardiac tissue, while improving cardiac function, enhancing global longitudinal strain, reversing peak longitudinal strain rate, and significantly reducing left ventricular hypertrophy and fibrosis
PMID 28988575
When performed under a dentists guidance, teeth whitening is generally safe and does not damage tooth enamel