Trichanthera gigantea (ketum ayam) is a species of flowering plant in the acanthus family, Acathaceae. Younger T. gigantea leaf was reported to contain good protein content with positive effect on livestock. This study aimed to determine the harvesting effect of T. gigantea leaves at 2 different stages of maturity (young: less than 2 months old, mature: 3 to 4 months old) on the nutrient and secondary metabolites compounds. The significant differences were determined at p<0.05. Young leaves showed significantly 5.44% higher protein, 4.04% ash, 3.19% fibre contents and 2.7% lower fat and 0.57% energy compared to mature leaves. Phenol and saponin were detected in both young and mature leaves, with the younger leaves contained 0.011% higher percentage in phenol and 3.22% in saponin. However, there is no significant difference in Ca (4.62%, 4.91%) and (0.31%, 0.19%) for both stages of leaf maturity. In conclusion, the young leaves showed higher nutritional value, suggesting potential as a partial protein source in broiler diets. However, feeding trials are needed to confirm its suitability.