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Eleven cases were eligible for inclusion [including two cavalier King Charles spaniels ]

However, a recent meta-analysis of 14 randomized, placebo-controlled trials in 2,149 participants with heart failure found that supplemental coenzyme Q 10 (30-300 mg/day) resulted in a 39% reduction in mortality (seven studies), improved exercise capacity (four studies), but had no effect on left ventricular ejection fraction (nine studies) compared to placebo (34)

So if your aim is longterm endurance improvements or a subtle shift in how your body uses fuel, plan for daily doses with meals especially carbohydraterich meals over several months

The role of mitochondria in aging

Choosing one over another usually depends on the objective under investigation and individual tolerance, rather than a universal best option