Addressing hair damage is essential for maintaining overall hair and scalp health. Previous studies have suggested that low-molecular-weight collagen peptides may support hair follicle biology through regulation of extracellular matrix homeostasis and cellular signaling pathways. In addition, recent preclinical studies have demonstrated that low-molecular-weight fish collagen peptides promote hair regrowth through activation of proliferative signaling and suppression of inhibitory pathways. However, their clinical efficacy in improving hair damage has not been clearly established. In this study, the efficacy and safety of low-molecular-weight collagen peptide GT (LMWCP GT) were evaluated in Korean adults with damaged hair. In a randomized, placebo-controlled trial, individuals aged 19∼60 years without alopecia but with mild to moderate hair damage received LMWCP GT (3 g/day) for 24 weeks. Compared with placebo, the treatment group demonstrated significant improvements in hair gloss, as measured using a gloss meter (SAMBA) and scanning electron microscopy, as well as in hair elasticity, assessed by tensile strength and hair diameter. Subjective evaluations further indicated improvements in overall hair condition, including gloss, elasticity, thickness, texture, fullness, and appearance. In addition, scalp elasticity was significantly increased in the treatment group. No treatment-related adverse events were observed. These findings indicate that daily supplementation with LMWCP GT (3 g/day) for 24 weeks is safe and effective in improving overall hair condition in individuals with damaged hair without alopecia.