While the most common form of creatine supplement, creatine monohydrate, is 99 percent absorbable, it takes more than just easy absorption for creatine to be an effective ergogenic aid. The limiting factor is the activity of a special transport protein in muscle, fittingly called the creatine transport protein. Not long after creatine was introduced to the commercial sports supplement market, studies revealed that insulin appeared to assist creatine uptake into muscle. Specifically, insulin stimulated the activity of a cellular mechanism called the sodium pump, which in turn powered the creatine transport protein. Based on that finding, creatine supplements evolved to contain a large dose of simple sugars.
Simple sugars are the most potent stimulus of insulin release, but studies showed that only a large insulin spike could favorably affect the sodium pump. You needed a whopping 95 grams of simple carbs for each five grams—about one teaspoon—of creatine. Since the suggested creatine-loading phase was 20 to 30 grams daily for five to six days, you were taking in a huge amount of simple sugar.
Unfortunately, eating so much sugar not only proved unpalatable but also increased the chance of adding bodyfat. Some scientists argued that a smaller amount of sugar would fail to spike insulin enough to prod the sodium pump and creatine transport protein. Then somebody had an epiphany and noticed the word sodium. Studies began declaring that sodium, not simple sugar, was the limiting factor in creatine uptake into muscle.
These days creatine is available in several forms, some containing simple sugars and others that rely on sodium to activate the pump. A recent study made a head-to-head comparison between the sugar and the sodium formulas. Nineteen weight-trained men, average age 29, received either a sugar-free supplement containing five grams of creatine citrate and 250 milligrams of sodium or a supplement containing five grams of creatine monohydrate and 36 grams of dextrose, a simple sugar. The supplements were dissolved in a pint of water and downed four times a day for five consecutive days, a typical creatine-loading phase. Strength and power tests were administered both before and five days after the subjects got the creatine. They were also tested for volume load, or how many reps they could complete after several sets done with loads equal to 70 to 80 percent of their one-rep maximums on the bench press and leg press.
Those in the sugar group gained more strength on the leg press than those in the sodium group. Both groups gained about the same amount of bodyweight, with the dextrose group showing a slightly higher one-rep bench press weight. Otherwise, the tests revealed no significant differences between the groups. So except for the improved strength on the leg press experienced by the sugar group, they made similar gains.
On the other hand, those in the sugar group took in 576 calories a day more than those in the sodium group. The combination of the added calories and the considerable insulin release suggests that sodium-based creatine supplements may be more suitable for those interested in losing bodyfat. Of course, then you have to deal with the large dose of sodium, which can result in water retention. Considering that the loading phase lasts only five days, though, that shouldn’t be a major problem, except for those with high blood pressure that is sodium sensitive. If you’re on an anabolic-steroid regimen, you’ll also probably bloat a bit, as steroids retain sodium in the body. IM
Healy, M., et al. (2008). The effect of two different creatine formulations on strength and power in resistance-trained men.J Str Cond Res. 22:41.