Hair is usually dry because it lacks natural oils and vitamins. Some applied oils replace these, like hair oils, but that solution is usually temporarily. My hair is very dry, usually frizzing, even with heavy conditioner. My friend passed me a helpful tip. Shower, either in warm or in cool water (cool water
doesn't dry out skin and hair too much). Shampoo, rinse, then lather up with a rich, thick conditioner. (Some "for dry hair" conditioners work well, but others may DRY your hair OUT so you will buy more. This is simply a way to make more money. Find one that works for you. I recommend Herbal Essence or Pantene.) Do not rinse immediately--take a fine-toothed comb and gently comb through your hair, from top to ends in each stroke. This distributes the conditioner to all parts or your hair and keeps the hair
manageable. After around five minutes of this, rinse. When you get out, wrap your hair in a towel, towel-drying and
blow-drying may/will damage your hair. Still damp, comb through again. This tip may take a few times for your hair to take effect.
Everyone's hair is different. Some are naturally dry while others are temporarily dry, (ie teenagers or preteens through puberty). My hair is fine and frizzy, and it worked for me!
*****Simple Solution** If this doesn't work, I have often tied my hair back in a ponytail or braid, spraying it with water. In a few hours I can let it down. Sometimes pressure can stop it from frizzing, but this solution isn't that accountable.