You must use the gerund (-ing form) in this case.
Dedicate and its derivatives take as complement a preposition phrase headed by to ...
He dedicated his life to music.
This work is dedicated to my wife.
Harold's dedication to his job precluded romantic relationships.
The to in to help people lost its prepositional sense about 700 years ago; it is now regarded as an infinitive marker. And the help in to help people cannot be understood as a noun; the noun help does not take an object.
The only verbform which can both act as the nominal object of a preposition and itself take an object is the -ing form, which is called a gerund when it plays the role of a noun.