No human pharmacokinetic data resolves it
FDA briefing document US Food and Drug Administration
The mechanisms include reduction of excitotoxicity and oxidative stress, enhanced neurotrophic factor expression supporting neuronal survival, angiogenesis improving blood flow, and modulation of dopamine and serotonin systems
However, every person responds differently to different treatments and surgery may not be necessary if you have a mild case of sagging skin
This is even before they schedule an initial consultation with the provider
Materials and Methods Study approval Animal procedures complied with the welfare guidelines of the European Community and were ethically approved by the Direction of Veterinary departments of Herault, France (agreement number 34.251) and the Languedoc Roussillon Institutional Animal Care and Use Committee, France (#CE-LR-0818)