Ah gotcha ...
This is really along the lines of say you're in your final 4 weeks of pre-competition prep, your diet is 100% on, your cardio & training are on schedule but the bear we call estrogen is fighting all our efforts by continuing to do what it is designed for - promoting fat depositing in those areas between knees & chest to help build a protective area & protecting energy (fat) stores to help increase the survival chances of a fetus.... So you throw in the topical fat burners or some similar thing to help fight it a little more.
Under those conditions (or similar tight diet & training) you will see discernible results. Just living a non-focused fitness-oriented life + the fat-burners = may / may not "see" a result. Fair to say?
I.e. what's her diet & training like? Based on that I would then venture to say if the supps of any sort would make a difference.