Creatine is not a weight loss supplement. Most of the weight is water weight, although it will significantly help with muscular strength/endurance. My first time taking it, which was my most successful, I put on 12 pounds in 14 days and upped my bench about 20% in 40 days. I'd been working out for a long time prior, so they weren't newbie gains. A lot of people find it difficult to keep those gains when they go off the creatine. I'm not sure how much of this is real and how much is mental.
If you want to tone your core you need to eat less and excercise more - specifically cardio. You still need to be lifting weights, so as to maintain lean body mass, which will otherwise be used as body fuel when on a calorie deficient diet.
Do not take creatine unless you are at least reasonably experienced with weight lifting. This doesn't mean 4 weeks. It means - know what you're doing in the gym, so that you can maximize the benefits of the creatine due to a good eating and lifting schedule. Also, newbie gains are substantial anyway in most cases, basically relieving the need for creatine.
I've been taking creatine for the past two months while cutting. This wasn't to help with muscle growth or fat loss, but to minimize some of the inevitable visual size loss accompanied with losing fat. I've felt that the creatine has done a decent job of keeping some fullness in my muscles while losing fat. The last time I cut I didn't do this and I got so skinny that I was starting to really hate it, forcing me to stop cutting and try and put some muscle on before getting down to the desired bodyfat, but this time I'm around 10 lbs heavier with a similar bodyfat percentage.
