Key points from article :
With ageing NAD+ levels in cells fall due to causes that are not clear yet.
Increasing levels of NAD+ in mitochondria produces its benefits by mitophagy.
Supplementing NAD+ precursors replete NAD+ in mitochondria.
Delays ageing and promote healthy longevity in accelerated ageing animal models.
But this only achieves "some degree" of improvement.
A collaborative research published in the journal Mechanisms of Ageing and Development.