MOTS-c

MOTS-c has been reported to act through AMPK and to engage PGC-1alpha-linked mitochondrial biogenesis pathways in skeletal muscle (Lee et al., Cell Metabolism 2015). Ubiquinol-10 supplementation in senescence-accelerated mice was reported to raise SIRT1, PGC-1alpha, and SIRT3 expression and to improve complex I activity (Tian et al., Antioxid Redox Signal 2014). The two are not co-administered in a published trial, but they share the same downstream node: the electron transport chain and PGC-1alpha-driven mitochondrial biogenesis. Preclinical evidence suggests CoQ10 status is one of the upstream variables that determines whether AMPK signalling can translate into functional bioenergetic gain.

Berberine is one of the most extensively studied small-molecule AMPK activators. In high-fat-diet mice, berberine prevented skeletal muscle mitochondrial dysfunction and increased mitochondrial biogenesis in a SIRT1-dependent manner; knock-down of SIRT1 abolished both the AMPK activation and the biogenesis (Gomes et al., BBA 2012). MOTS-c is reported to activate AMPK via inhibition of the folate cycle and de novo purine biosynthesis (Lee et al., 2015). Because both molecules converge on the same AMPK/SIRT1/PGC-1alpha axis in muscle, they are commonly discussed together in mechanistic reviews, although no head-to-head human co-administration trial has been published.

Alpha-lipoic acid is a mitochondrial dithiol cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. In aged rat brain, alpha-lipoic acid lowered mitochondrial lipid peroxidation and 8-oxo-dG, restored reduced glutathione and ATP, and recovered electron transport chain activity (Palaniappan & Dai, Neurochem Res 2007). MOTS-c is studied as an exercise-induced regulator of mitochondrial homeostasis (Lee et al., 2015). The literature does not pair them in a clinical trial, but the shared mechanistic terrain - protecting electron transport capacity and lowering oxidative load on mitochondria - is the rationale most often invoked when the two are discussed together in mitochondrial-medicine reviews.

Vitamin D receptor signalling has been reported to govern mitochondrial oxidative capacity in skeletal muscle: VDR loss-of-function in myotubes lowered respiration rate and ATP production, and deficient subjects showed impaired exercise-induced energy production (Salles et al., Communications Biology 2022). A separate review summarised data linking vitamin D status to ROS handling and satellite-cell-driven muscle regeneration (Latham et al., Frontiers in Physiology 2021). MOTS-c is reported to act preferentially on skeletal muscle and to be exercise-inducible. Adequate vitamin D status is therefore one of the documented permissive conditions for muscle mitochondrial output, on which MOTS-c is mechanistically dependent.