"13. Kant shows the basic identity of the first and second formulation of the categorical imperative. Those actions that, on the first formulation, cannot be universalized without contradiction (for example, committing suicide or refusing to help the needy) will be seen on the second formulation to be inconsistent with the idea of humanity as an end in itself."
Great Traditions in Ethics (ninth edition)
Denise, Peterfreund, White
Killing yourself is against Kantian ethics?
Why - its not your moral duty to stay alive is it?