infect vs regeneration

Regeneration will not work against infect.

Regeneration will protect a creature from destroy effects or lethal damage.

it will not protect the creature from having 0 toughness, thus putting it to graveyard.

701.11. Regenerate
701.11a If the effect of a resolving spell or ability regenerates a permanent, it creates a replacement
effect that protects the permanent the next time it would be destroyed this turn. In this case,
“Regenerate [permanent]” means “The next time [permanent] would be destroyed this turn,
instead remove all damage marked on it and tap it. If it’s an attacking or blocking creature,
remove it from combat.”
701.11b If the effect of a static ability regenerates a permanent, it replaces destruction with an
alternate effect each time that permanent would be destroyed. In this case, “Regenerate
[permanent]” means “Instead remove all damage marked on [permanent] and tap it. If it’s an
attacking or blocking creature, remove it from combat.”
701.11c Neither activating an ability that creates a regeneration shield nor casting a spell that
creates a regeneration shield is the same as regenerating a permanent. Effects that say that a
permanent can’t be regenerated don’t prevent such abilities from being activated or such spells
from being cast; rather, they prevent regeneration shields from having any effect.