Recall the formula.

Professor Andy Munro was never that skinny kid, he was always that overweight person. No matter how much he diets or excise. He couldn't lose the weight. Then he found out, he had special gene, but he didn't know why. Many, many years later he was experiment on ways, that you get a better, thinner more younger body.

He experiments in several combination, he believed that he got the right combination. So, he is experimenting on himself. At first it was nothing, but barely half an hour to an hour later. He started changing, he got thinner, more younger looks. He looked more and more feminine in appearance. When he found the formular, he was surprised and shocked, and happy of sorts.
As he looked at his new thin, younger, feminine form, Andy was please. Thou he didn't like being a woman, so much. But he felt that he could probably enjoyed it.
Any first several thoughts were clothes to wear, the clothes, he was now wearing were much too big, to lose on his feminine body. the other thing was that was it temporary or permanently.
Thou it was temporary and lasted for 12 to 18 hours in his new feminine body, he enjoyed being a girl, thin, young and sexy. So needed to find a more permanent to stay as Alaina.
After Andy been take the formula for several weeks. He wasn't sure, but the last weeks, Andy was more Alaina each time. Andy wanted to stay Alaina always now.
Was it than special gene he/she had. Or was it the combination, of his/her genes and formulas. As Andy/Alaina was searching for that right combination. To be finally Alaina. She is enjoying being a girl, so, so much. She like how she looks, how being a girl. Especially the sex as a girl. If she finds that right mixer, or this that she takes it long enough that she be a girl for forever?