3-Aminopropionitrile fumarate (2:1) is a lathyrogen which inhibits crosslinking of collagen. IC50 & Target: Collagen^[1]. In Vivo: Twenty days after the induction of tendinitis, intralesional treatment with 3-Aminopropionitrile fumarate (2:1) (BAPN-F) is performed and the contralateral limbs receive saline. A biopsy is obtained and gross and histopathological analysis is performed on the 150 th day of the experiment. The collagen fibrillar alignment pattern in the healing area is better in the 3-Aminopropionitrile fumarate (2:1) group submitted to controlled exercise than in the other group, as observed by sonographic and histopathologic examination. The present results indicate that 3-Aminopropionitrile fumarate (2:1) in combination with controlled loading improved scar remodeling and tendon wound collagen maturation^[1].