My g f is concerned about her Thermobol dose she thinks that 3 a day is too much for a girl and only takes 2, is this suitable for her?

She is currently drinking Promax diet and Thermobol as part of a good diet and regularly exercises 4 times a week.

She is 5.3ft and around 7 stone 11 or so, her concerns are as she is small she will be hyper at work and make a fool of her self, lol, she currently takes two and feels shakey,

I tell her its because she only has taken it a day or so and her body is not used to it yet.

Any advice please??????
Thanks!

p.s i take three and feel fine