Board Thread:Wiki Discussion/@comment-28749761-20160804161044/@comment-27701762-20160804162355

Presumably when Flowey captures the various characters he does no damage to them. There's no indication that he does any actual damage. Just that they are trapped.

We go with Sans having 1 HP because that is what it says in the data files. LOVE is tied to HP for the protagonist (and presumably other humans), but it wouldn't make sense for monsters. Since all monsters are peaceful creatures, they don't really have any LOVE. Asgore and Undyne are perhaps the only exceptions, but if their HP levels were explained through LOVE, then we'd fall into a problem in explaining Toriel and Papyrus (along with plenty of others). Instead, HP is probably variable depending on other factors, which LOVE can increase, but is not the sole determinant of max HP.