Walk into any supplement store and you're likely to see a couple dozen products advertising creatine in them. There's probably a bunch more that have creatine in them but don't advertise it as the main event.
But, is all creatine the same?
The answer is quite simply "No."
Most of the creatine you come across is creatine monohydrate. It's a very cost effective supplement to produce, and has the same benefits of creatine HCL. The problem is it comes with a non-trivial list of side-effects.
The main issues come from the solubility and absorbability of creatine monohydrate. There is some varying research on this, but the literature generally points to anywhere from 15% to less than 3% of the original amount of creatine taken is transported across the intestinal barrier.
The result is the excess creatine sits in the intestine, which draws water into both the intestine and the subcutaneous space.
This is the cause of the fabled bloating and stomach upset that many people report.
The key to creatine HCL is the addition of the hydrochloride group. Adding it to the creatine molecule lowers the pH of the creatine, making it more acidic. This drastically increases the solubility of the creatine in water. In fact, creatine HCL has been shown in a lab to be about 40 times more water soluble than creatine monohydrate.
Further research shows that creatine HCL is absorbed by the intestines about 60% better than monohydrate.
Essentially, that means you have to take a smaller dose and get more out of it.
All creatine is not created equal. And the research has shown that creatine HCL is the superior version.