There is no one "best" hair porosity as each type of hair porosity - low, medium, and high - has its own unique strengths and challenges.
Low porosity hair, with its tightly closed cuticle layer, is less prone to damage from environmental factors such as heat and chemical treatments, but can be more difficult to moisturize and style due to the difficulty in absorbing products.
Medium porosity hair has a more open cuticle layer, making it easier to absorb and retain moisture and nutrients, while still maintaining some resistance to damage.
High porosity hair has a highly open cuticle layer, making it easy to absorb moisture and nutrients, but also more prone to damage and breakage from environmental factors such as heat, chemical treatments, and friction.
Ultimately, the best hair porosity is the one that is healthiest for your individual hair type and texture. It's important to understand your hair's unique needs and adjust your hair care routine accordingly. By using products and techniques that cater to your hair's specific porosity, you can help your hair look and feel its best.