u/TheJoshRosebrook411

HAIR DENSITY is misunderstood. You cannot change hair density. Products claiming to are misleading and take advantage of your lack of hair chemistry knowledge.

HAIR DENSITY is the number of individual hair strands growing on your scalp. It’s measured low to high by how close your hair follicles are to each other. You cannot create new follicles on your scalp unless you get a hair transplant. "Hair density" products are marketed with a claim they can't deliver. At most, these products can improve hair TEXTURE, thickening the individual strands you have.

HAIR TEXTURE is how thick the actual strand is. Hair texture (which most confuse with hair type) is measured from fine, medium to course.

HAIR TYPE is how straight, wavy, curly to coily hair is.

SPF 100 sunscreens give a false sense of extra safety. SPF 100 doesn't give you double the protection of SPF 50. SPF 30 blocks about 97% of UVB. SPF 50 blocks about 98%. SPF 100 blocks about 99%. The diminishing returns mean SPF 100 isn't "3x better," it's about 2% better UVB protection. 

Yes 1 percentage point is "double" the protection against the rays that get past SPF 50 but it's only a 1 percentage point difference and skin can't tell the difference between 98% and 99% in real world application. 

The problem is that MOST people applying it will believe it's double protection of SPF 50!!

It's absolutely not.  SPF "100" also lands on many psychologically with a sense of 100% protected, and tend to reapply WAY less.

No sunscreen protects 100%, not even close. Anything over SPF 30, applied correctly and reapplied, is what actually matters.