Laser hair removal did not work for me, what might be the reason?

I am a 25 year old female, light skin and brunette hair. I recently had 8 laser hair removal sessions 6 to 8 weeks apart using the ND: YAG Gentle Max Pro by Syneron Candela on the underarms, half leg and bikini. During the 8 treatments hair grew back slightly slower but no major difference and now I have finished the course it is like I never had it. I went to a popular experienced clinic and had blood tests confirming my hormones are normal. Why has it not worked at all? Thank you.