Buying vitamins for hair skin and nails

[hanette]

Hi

I take the superdrug Hair, Skin and Nails supplement and need to stock up.

Which got me thinking - how can I differentiate between one rand and another of the ingredient list is pretty much identical? Are there other differences in quality? Any brands better than others? Are the eBay suppliers and good?

Thanks!

I've only taken the Holland and barret one, they are good but expensive and I'm sure cheaper would be just as good but don't want to mess anything up by switching.