Question: what is the best shampoo for weak hair?
Answer: Best For Strengthening: Kérastase Densifique Bain Densité Shampoo. ... 
Best For Age-Related Thinning: Andalou Naturals Argan Stem Cell Age-Defying Shampoo. ... 
Best For Thinning Caused By Dandruff: Dove Dermacare Scalp Anti-Dandruff Shampoo. ... 
Best For Color-Treated Hair: Nioxin System 4.