Bait Additives - Do they work?

DO the crab/mackeral/sandeel additives to bait actually work?
Has anyone noticed the difference?
I was thinking of getting some to use with frozen baits to give a bit more scent.
Thanks
JK

I've used some Italian made stuff called UltraScent that my local tackle dealer gave me to try out - it actually seems to have a negative effect.

I think a fresh mackeral strip is the only way to go.

The additives may be worth a go with frozen bait though...

Who knows, really?

But it can't hurt, and if it gives you extra confidence then it's not a bad thing.