Why different size nolva pills?

[superfreak]

I have two different size tamoxifen pills, one is pink with 20 and a 'n' on it the other is a white generic version. The white one is about 2 times bigger than the pink one. I know the white pills are legit but Im wondering if the pink ones are and why they are so much smaller. Is it because they are more concentrated?

 

[MrRobRage]

or maybe a different dosage?

 

[superfreak]

Im assuming they are both 20mg cause they both have 20 on them. Also, how would I know if its working right away or not? would it take a while to notice something? Anyone?