This study addresses the growing consumer demand for effective and sustainable hair care solutions by evaluating a novel bioactive crosslink repair complex designed to restore chemically damaged hair. The complex comprises itaconic acid, arginine, D-panthenol, and polysaccharides from linseed and chia, which work synergistically to promote fiber crosslinking, protein restructuring, and cuticle barrier restoration. The complex was incorporated into two formulations: a bleaching mixture as a protective agent and a leave-in conditioner as a repair treatment for chemically damaged hair. The protective efficacy was assessed through tensile strength measurements, differential scanning calorimetry, combability tests, shine evaluation, and scanning electron microscopy. The repair potential was evaluated using differential scanning calorimetry and tensile strength analysis. Results demonstrated that incorporating the complex into the bleaching mixture significantly enhanced break stress, denaturation enthalpy, shine, and combability, while maintaining improved cuticle alignment. The hair repair evaluation showed that post-treatment application of the complex successfully restored hair tensile strength and denaturation. These findings confirm the dual functionality of Bioactive Crosslink Repair Complex as both a protective and reparative agent, highlighting synergistic mechanisms in preventing and reversing chemical damage to hair fibers. This bioactive approach offers a promising alternative for hair care formulations targeting chemically treated hair.