I have been using Pearl Drops since my teens and although I do not have perfect white teeth 
(one can dream) I can say that I don't have yellow teeth.

Anyway before I bore you all with stories about my teeth let me share Pearl Drops newest release which is an overnight serum that not only helps to whiten the teeth but protects the teeth and gums, 
which pleases me to no end as I do tend to worry that whitening products will be the demise of my teeth,
I can't be the only one?

Basically to use you simply dispense a pea amount of serum and gently massage onto the teeth and leave overnight or if that is a daunting prospect then simply leave on for at least 30 minutes 
and remove by brushing your teeth and rinsing your mouth.

I have problematic gums and have used this for a few nights now and can safely say that not only do I still have all my teeth (woo!) but it did not burn, hurt or damage my teeth or gums in any way. 
I have of course not used this long enough to see any visible results as of yet 
but if I do in shall update in the weeks to follow.

Pearl Drops Beauty Sleep Serum* £3.49/20ml and is available from Boots, Asda and Superdrug.