Sirtuin from GDRLabs is claimed to be a “youth gene activator” that promotes regeneration of microvessels, among other beneficial activities. Would this be helpful for my client with his vessel problems? If so, does that mean the product has benefits for larger vessel narrowing as well?

This will help to some extent, and it will help him to have coverage for vessels in general, regardless of size, so it represents a useful addition to other things he is taking. This is true for many, many others. Often it is the weakest link that turns up in having a symptom appear or a routine diagnostic check with imaging. Many things will not be discerned with routine physical examinations, so having ongoing prophylaxis using an Antiviral Regimen routinely, is the best way to help the most people.