If it's working, I wouldn't worry about questioning it! I've been type one for over 20 years and, like you, find I put weight on easily if I'm not careful. Also find it very hard to lose weight.
The only thing I would say is that the weight loss will probably slow down once your body gets used to the tablets. When this happens you may, in time, find that you start to out the weight back on. Make sure you make some adjustments to your diet/lifestyle to stop that happening. For me, the only thing that works is restricting my calorie intake to less than 1,000 a day and exercising 5-6 tines a week. Hate the fact that all my friends can just cut out the crisps and lose five pounds in a week!
Em