Thanks for the replies.
I'm not really sure how checked baggage screening works at the transit airport - is anyone able to clarify for me? Would be good to know out of interest too.
@ ARNSpoty / Dubaian - my thoughts too. If my final destination was Dubai then I wouldn't attempt to take the supplements. Since I will only be on transit there then I think if I did do it, I'd probably be fine taking it as checked baggage from UK.
@ Load Toad - they are not pills but in powder form. It's also completely legal to available buy in Dubai in shops there, but your last sentence is the reason why I will 'bite the pillow' as you put and buy at the destination instead of risking anything.
thanks guys.