This brand has some gems... and then there is lots of nonsense.
The original K18 peptide was only available is salons and was added as part of the bleaching product to reduce breakdown of hair follicles during bleaching... so actually prevents damage. This product is amazing.
The first one that was sold in store (the K18 pro repair) is a VERY expensive tiny bottle, but a little goes a long way. You use it instead of conditioner after shampooing, and leave it in. For repairing damage... amazing. For anything else conditioner does (adding slip, shine, moisture) I found it did help, but it is a lifesaver after chemical treatment.
I just tried the molecular repair oil and it left my hair soft, but for the price point I feel like it wasn't that different than other hair oils.
Shampoo and conditioner both left my hair feel lackluster and a little strawlike.
They have a heat protecting leave in that I found very greasy.
The price points are absolutely ridiculous for some their products, but if you are doing anything requiring bleach, the propeptide and prorepair are totally worth it.