No matter what specie of fish you are after they all use their sense of smell. Some fish have a much more sensitive olfactory than others like catfish, who feed almost exclusively by smell.  Northern pike feed primarily by sight but use their sense of smell to detect danger. 

We come in contact with a lot of things that are repulsive smelling to fish like gasoline, hand lotion, cologne, sun screen and others. Even if you are extremely careful not to get any of these things on your hands which would subsequently transfer to your bait, we still stink. 

Humans have a substance call L-Serine which is an amino acid and has been found in many studies to be very repulsive to fish. Some people have higher levels of L-Serine than others but don't worry - you don’t need to be tested or go to the doctor and have anything removed, but there are things you can do to help mask your nasty odors. 

There are several brands of no-scent soaps on the market that do a great job but need to be used several times throughout the day. Be sure to get one that is non-toxic and biodegradable so you can wash your hands in the water you're fishing without harming the environment. 

I have to admit that I don't use these soaps as religiously as I should; instead I rely mainly on scents. Most of the add on scents are called attractants but I believe this is a bit misleading. Yes dipping, spraying or rubbing your bait with a scent or buying soft plastic baits with the scent impregnated in them will get you more bites but they don't work miracles. Let me explain; fish have a strike zone, this is the area that a fish is willing to feed in, the more active the fish are, the larger their strike zone is and vise versa. When fish are lethargic their strike zone shrinks, sometimes to within inches of their nose.

Scents will not draw a fish outside of its strike zone, if the fish are not active and feeding they aren't going to swim an extra 5 feet to bite your bait because it smells good. What scents will do is up your odds that a fish will bite your bait or lure when it is in the strike zone and hold onto it longer giving you time to react and set the hook. 

I've watched fish in clean water touch a bait with their mouth and not bite it. I did my job and found a lure that the fish was interested in and put it in the strike zone but have to assume they smelled something unnatural and at the last second decided not to eat it.  I didn’t have to see this twice to make me a believer in scents.

Transferring scents is not limited to artificial baits, grabbing some live bait and putting it on your hook can transfer enough bad smells to stop a fish from biting. Fish being turned off by a negative smell is even more evident with the older, larger fish, since the older a fish gets the larger it olfactory lobe becomes, thus enhancing its sense of smell. Washing your hands with a no-scent soap and masking unpleasant odors with fish “attractants” will get you more bites so I guess you can say that it makes good scents. Until next time keep your lure wet!