According to my dictionary, a laxative is meant to stimulate the bowels, that is to say, to ease constipation. Bran seems to be a good breakfast cereal for this, as it is a natural laxative. Here in Britain we have All Bran, "The Natural Laxative Food" says the adverts, along with Bran Flakes, and whatever.
In your query, you do not say whether constipation is a problem or not. Do you link taking laxatives with your training program? Here again you don't say. As a triathlete and long-distance cyclist, I found no evidence in myself that laxative has added any boost to my performance, except maybe a faster run to the restroom!
As for laxative addiction, Bran is a roughage, or fibre, not a drug. I have eaten and enjoyed All Bran for breakfast, but I have never been addicted to the cereal, in fact for me, Bran does not taste that fantastic, and in a sense I was happier to switch to another, tastier cereal.
I hope that this may be of help to you. Good luck!