Over the counter wormers, any good?

[CuriousMama]

My dog is due worming and I wondered if there's any point buying a wormer from my local pet shop? He gets very distressed at the vets so don't want to put him through it if there's no need. TIA.

Oh and if so which one as there seems to be so many?

I thought they had to weigh them? I hadn't thought of that thanks.

Thanks for that.