Prolongation of the life-span in mice adapted to large amounts of L-dopa

Various concentrations of L-dopa (levodopa, L-3,4-dihydroxyphenylalanine) were incorporated in the diets of young male Swiss albino mice, and the highest concentrations to which these mice became adapted within 3 weeks were determined. One such concentration administered indefinitely eventually induced a youthful appearance, a significantly prolonged life-span, but also corneal opacities compatible with traumatic or chemical keratitis.