Does the number of ingredients in a potion affect its strength?

Does anyone know if there is any benefit in mixing ingredients where 3 of them share the same effect?

I created a potion that had 2 ingredients with fire resist, and then another where 3 ingredients had fire resist, and the fire resist stats were the same with both potions.

I was wondering if this is true for all effects or if maybe some effects had boosted stat if all 3 ingredients shared it?

Nope, mixing more than two ingredients with the same effect doesn't create a stronger effect.

The only thing that changes the strength of the effect is your current alchemy level + perks + enchantments.

Given this, theoretically the strongest potion or poison that can be made will have at most 6 effects.

Reference: Personal experience + I saw it on a wiki page I can no longer find.