Which hair serum is best for dry hairs and how/when to apply it?

I would say the hair serum from garnier fructus is one of the best out them that is affordable. You can place very little after your hair is towel dried, and if you blow dry your hair you can apply alittle more afterwards..It smells great and I really love it! I also love all of their hair products. Make sure to only use alittle bit though, because if you use alot it can make your hair look oily. Hope I helped!

Which hair serum is best for dry hairs and how/when to apply it?

i have very dry, frizzy hair so i use frizz ease serum and i apply it when my hair is damp

Which hair serum is best for dry hairs and how/when to apply it?

I use Paul Mitchell brand, there are a few of them for different effects. The best way to apply it is to blow dry your hair for just a couple of minutes first then rub it on your hands and run them through your hair. After doing this to all the sections of your hair, comb it through with a wide toothed comb.

Which hair serum is best for dry hairs and how/when to apply it?

If you are using serum to moisturize that isn't the way to go. Try using shampoos dedicated to moisturizing. If you are using serums to style your hair then try Paul Mitchell - Gloss Drops. Put this in your hair when wet and style as desired. Paul Mitchell has an entire line dedicated to Moisturizing your hair. From Shampoos to Styling Products. I also love their hair smoother called Super Skinny. It smooths and adds shine.