"OK, after digging up my old EAS supp review, here is what Bill Phillips had to say on Coenzyme Q10:
"There is no disputing the crucial role coenzyme Q10(CoQ10) plays in energy production throughout the body. It has also been documented to have potent antioxidant characteristics(1,2). All of that is fine and dandy, but will taking oral doses actually help athletes perform better?
The answer appears to be NO! And for that reason, my stance on this supplement has not changed since I put it on the "F" list in the 1996 Supplement Review. As a matter of fact, I have come across even more evidence to suggest coenzyme Q10 has no effect on exericise performance in healthy individuals and may even hinder it.
One very solid study using a double-blind, cross-over design looked at the effects of 300mg/day of coenzyme Q10, plus a few other nutrients, on performance of 11 elite triathletes. No significant differences were noted in ANY performance parameters between coenzyme Q10 group and the placebo group(3). One other study performed on untrained men using 150mg/day reported similar results.(4)
Not only does this stuff not help, it may actually hurt your muscle-building efforts! A new study involving coenzyme Q10 and 15 healthy males showed that the stuff, under conditions of intense exercise, may actually cause cell damage secondary to possible pro-oxidant activity when taken in supplemental amounts.(5)
Don't waste your time or money on this one! If you just happen to have some coenzyme Q10 lying around the house, you might consider mixing it with a little water and trying it as a weed killer."
(1) O. Spigset, "Coenzyme Q10(Ubiquinone) in the Treatment of Heart Failure. Are Any Positive Effects Documented?" Tidsskr Nor Laegeforen 114.8 (1994): 939-942
(2) C. Weber, et al., "Effect of Dietary Coenzyme Q10 as an Antioxidant in Human Plasma, " Mol. Aspects Med. 15 Suppl. (1994): 97-102
(3) I.P. Snider, et al., "Effects of Coenzyme Athletic Performance System as an Erogenic Aid on Endurance Performance to Exhaustion," Int. J. Sport Nutr. 2.3. (1992): 272-286
(4) D.A. Porter, et al., "The Effect of Oral Coenzyme Q10 on the Exercise Tolerance of Middle-Aged Untrained Men, " Int. J. Sports Med. 16.7 (1995): 421-427
(5) C. Malm, et al., "Supplementation with Ubiquinone-10 Causes Cellular Damage During Intense Exercise," Acta Physiol. Scand. 157 (1996) : 511-512