The acids are natural fruit acids, some can be harmful or harsh on your locks so it would depend on which one you are referring to.
Also alcohol content is a big culprit of shampoos. They try too hard to 'smell great' and add alcohol which will dry out your hair. Not good, especially if color treated!
Garnier Fructis is actually a 'good brand' when you look at some of the common ingredients to avoid in hair care. Another great one is L'Oreal's Vive line. Unfortunately Pantene doesn't make the cut.
Great tips to shop by:
Avoid any shampoo with Sodium Lauryl Sulfate (SLS) or Sodium Laureth Sulphate (SLES).
They are carcinogens, or cancer-causing agents.
Fruit additives to avoid in hair care:
Avocado
Balm Mint
Balsam
Essential Oils
Eucalyptus
Grapefruit
Horseradish
Lavender Oil
Lemon
Lime
Menthol
Orange
Papaya
Peppermint
Rose
Sage
Thyme
All else should be safe.
No matter what you use, it would be a good idea to do a 'mask' once a week. This will help repair and revitalize your hair to undo any minor damage your products contribute to.
Anything that says hair mask will do, but be prepared to dish out anywhere from $15-$60 for them.
A cheap natural alternative? Of course! Try one of these!
Olive Oil Hair Mask
Mix 5 tablespoon of olive oil with 2 eggs. Apply throughly to hair. Wrap head with plastic wrap or a shower cap. After 15 minutes rinse well.
Honey & Olive Oil Hair Mask
Mix 2 tablespoon honey with 3 tablespoon olive oil. Apply throughly to hair. Cover hair with plastic wrap or a shower cap. After 15 minutes shampoo and rinse well.
If you are not a meat-eater, I'd do this once a week religiously.
Hair is made of protein. A diet rich in protein can avoid most unhealthy hair problems. An unhealthy diet and stress/tension in life affect your hair.
Stay beautiful!
Hope this helps.