All proteins are strengthening proteins to some degree but here are more specific characteristics of these proteins:
Collagen Proteins -- known for increasing elasticity in the hair.Silk Proteins -- known for softening the hair.
Wheat Proteins -- a moisturizing and strengthening protein. Known for increasing the hair's ability to maintain & receive moisture.
Keratin Protein -- responsible for keeping the hair strong and pliable. This is the strongest of the (hair product) proteins and is actually the one hair is made from. This one re-structures hair that has been damaged or broken down by chemicals. It helps to replace the amino acid cysteine which is the main one lost during chemical processing. This is the heavy duty protein.
If you see the following as an ingredient:
*a) Keratin protein -- the will re-structure and strengthen the hair cuticle (the outer layer only & the most important layer
*b) Hydrolyzed Keratin Protein of Keratin Amino Acids -- this means that the Keratin molecules have been broken down and are small enough to go beyond the cuticle and penetrate the hair shaft. It will strengthen all 3 layers of the hair. That is why the term "deep conditioning" technically only refers to this kind of treatment using penetrating proteins.
*c) Hydrolyzed Human Hair Keratin -- This is an exact match for the keratin your hair has (or has lost due to chemical processing). This is the highest quality and most potent keratin that can be used in hair products.
*Vegetable protein -- Vegetable protein absorbs more easily into the hair shaft (than animal protein) and does not create build-up, leaves the hair very shiny, radiant, luxuriant, and healthy.
*Animal protein -- Animal protein breaks down into fatty acids, which coats the hair and create residual build-up.
Silk Amino Acids/Protein -- Natural Silk is the strongest, natural fiber known to mankind. Discovered in Japan and has been used for centuries in all kinds of products that require durability. Silk has a tiny molecule that can penetrate the entire hair shaft deeper than all other proteins without adding any weight leaving the hair feeling clean and non-greasy.The Keratin is some reconstructors should not leave your hair hard like the Aphogee Treatment for damaged hair (which contains hydrolyzed animal protein). This treatment hardens on your hair for a reason and is used with mild heat. A moisturizing conditioner is a must with this in order to soften like KeraCare Humecto.Reconstructors that contain keratin and other proteins are supposed to have enough moisture to soften the hair therefore leaving your hair with a nice protein/moisture balance.