Forum:Double up on tonics?

Hello all! I'm playing through Bioshock 1 again for the first time for probably two years and I have a question. What if I were to use two of the same tonics? Would it combine the effect? Or would it just nullify the weaker one? For example if I were to use Hacker's Delight 1 (which lets say gives you 1 HP) as well as Hacker's Delight 2 (which I'll say gives you 2 HP) would I get 3 HP after hacking something or just 2?