Google WD-40 and see that the manufacturer does not give out info on their "secret formula", but it has been analyzed by others. Take a look.
I used to hear rumors that it contained some Menhaden oil...don't think that is correct. And the manufacturer does not recommned it for fishing use.
Not something I'd use on fishing lures/bait or in any way directly introducing to the waters I fish in. Some say it covers up the human scent on fishing lures....may be...but lots of noxiuos and/or poisonous chemicals will cover up your scent...not saying WD-40 is poison..but just because it may cover your scent does not mean it will attract fish.
It's good stuff for some purposes...but not on my bait/lures....
...And others will probably swear it's the best fishing invention since the first hook was crafted.