How Does Coenzyme Q10 (CoQ10) Work?

Background

In recent times, there has been increasing interest in Coenzyme Q10 (CoQ10) as a dietary supplement that can impact cellular energy and combat the damage caused by free radicals [1-4]. CoQ10 is a fat-soluble substance similar to a vitamin, present in all cells [5]. It plays a crucial role in various important functions in the body, including transferring electrons within the mitochondrial oxidative respiratory chain for ATP production, acting as an essential antioxidant and supporting the regeneration of other antioxidants, influencing membrane stability, fluidity, and permeability, and stimulating cell growth while inhibiting cell death [5-7].

CoQ10 has been used as a supplementary treatment for chronic diseases like Chronic Heart Failure (CHF), muscular dystrophies, Parkinson’s disease, cancer, and diabetes in clinical populations [8,9]. In CHF patients, who have lower than normal CoQ10 levels, supplementation has shown to improve stroke volume, ejection fraction, and exercise capacity based on double-blind, placebo-controlled studies [4]. Athletes may also experience CoQ10 deficiency due to increased metabolic stress and free radical formation during intense training [7,10,11]. Considering these findings and our current understanding of CoQ10’s functions in the body, it has been speculated that dietary supplementation with CoQ10 could benefit not just clinical patients but also healthy, active individuals who may potentially face CoQ10 deficiency [3].

However, studies investigating the potential ergogenic (enhancing physical performance) value of CoQ10 in athletes have yielded mixed results [4]. Some studies have shown that CoQ10 supplementation (60-100 mg/day for 4-8 weeks) improves aerobic power, anaerobic threshold, exercise performance, and/or recovery after exercise in trained athletes and untrained individuals [12-14]. On the other hand, other studies using similar dosages (60-150 mg/day for 3-8 weeks) have found no significant benefit on maximal or submaximal exercise capacity in untrained and trained individuals [15-19].

One possible explanation for these inconsistent findings is that the absorption of CoQ10 into the mitochondrial membrane or non-deficient tissues is relatively inefficient. CoQ10 is a large, hydrophobic molecule [20], causing slow and limited absorption into tissues. To address this issue, researchers have examined the bioavailability and absorptive properties of different CoQ10 preparations, including fast-melt tablets, effervescent tablets, soft gelatin liquid capsules, and hard shell powdered capsules [21]. The results indicate that fast-melt tablets and effervescent formulations offer quicker delivery of CoQ10 to the blood while exhibiting similar pharmacokinetic properties as the soft gel and hard capsule forms of CoQ10 [21]. These findings suggest that providing CoQ10 in a fast-melt or effervescent form may enhance its delivery and uptake into the muscles, potentially improving bioavailability and promoting a greater metabolic and/or ergogenic impact. However, the effects of acute and chronic ingestion of a fast-melt form of CoQ10 on muscle CoQ10 concentrations, exercise performance, and markers of oxidative stress remain unknown.

In light of this, a study was conducted to investigate whether acute (single-dose) and chronic (14-days) supplementation with a fast-melt form of CoQ10 would affect muscle CoQ10 concentrations, improve anaerobic and aerobic performance, and have any impact on markers of oxidative stress in both trained and untrained individuals.