Mitophagy is a specialized form of autophagy (cell self-removal) that performs the selective removal of damaged or dysfunctional mitochondria.  Superficially, that would seem to be a very beneficial process.  It is a natural cellular quality control process that seems intended to maintain cellular health and to ensure good mitochondria for ATP energy production.  There are several small-molecule supplements that are known to be mitophagy boosters: Urolithin A, Spermidine, Curcumin, Quercetin, and Alpha-Lipoic Acid.

However, there is a basic problem with mitophagy.  It senses damaged mitochondria by a process that is triggered by ROS damage of lipids (cardiolipin) and proteins (TOM/TIM) on the mitochondrial surface, and this damage tends to occur mainly in those mitochondria emitting the most ROS, which can be taken as an indication that, although not the cleanest performers, they are the ones most actively producing ATP for cell energy.  On the other hand, the mitochondria with serious mtDNA damage produce little to no ATP and are likely to have little to no ROS-produced surface damage.  Therefore, mitophagy intended to improve mitochondrial quality, is actually likely to do more harm than good by clearing away active mitochondria while leaving the severely damaged one alone.  As cells lose some of their active mitochondria to such mitophagy, the active ones that survive may react to the growing energy shortage by “going into overdrive” and producing a higher level of ATP and ROS, contributing to a viscous feedback cycle.  The process seems likely to contribute to the age-related ATP energy shortage manifested as the symptoms of old age.

This leads me to the conclusion that taking booster supplements like those listed above that promote mitophagy may not be such a good idea, and that a supplement to suppress mitophagy might be preferable.  There are three OTC mitophagy suppressors that are readily available: the sleep hormone Melatonin, Coenzyme Q10, and its proprietary derivative MitoQ (mitoquinone).  I take Melatonin and liposomal Coenzyme Q10 every night, and I only take Quercetin every 3-4 months in senolytic sessions.