Coenzyme Q10

CoQ10 is a lipid-soluble quinone at the heart of the mitochondrial energy chain, and it is among the best-selling supplements [1][7]. The body's own production falls with age [7].

Heart failure has the most important trial. In Q-SYMBIO, 420 patients with chronic heart failure were randomised to CoQ10 or placebo on top of standard care. Over two years, major adverse cardiovascular events occurred in 15% on CoQ10 versus 26% on placebo, and cardiovascular and all-cause deaths were lower. Short-term endpoints did not change [2].

Statin muscle symptoms have produced conflicting meta-analyses. One pooled 12 trials and found less muscle pain, weakness, cramps and tiredness [3]. Another pooled seven trials and found no benefit for myalgia or statin adherence [4]. A review reads the overall weight of evidence as supportive [1].

Migraine: across six trials CoQ10 reduced the frequency and duration of attacks but not their severity [5]. Blood pressure: a Cochrane review found no clinically significant effect in primary hypertension, based on very few trials [6]. A larger meta-analysis in people with cardiometabolic disease found a 4.8 mmHg fall in systolic pressure, largest at 100 to 200 mg a day [8].

CoQ10 shuttles electrons along the mitochondrial respiratory chain, which is how it supports ATP production [7]. Pairing it with statins rests on a proposed link between statin treatment, the body's CoQ10 and statin muscle symptoms [3].

Supplements contain either oxidised CoQ10 (ubiquinone) or its reduced form, Ubiquinol.

Q-SYMBIO found long-term CoQ10 treatment safe in heart failure [2], and a Cochrane review noted it was well tolerated where adverse effects were reported [6].

Warfarin is the classic concern. In a randomised, double-blind crossover trial in 24 patients on stable long-term warfarin, CoQ10 did not change INR or the warfarin dose needed [9]. INR monitoring when starting any supplement is still sensible.