Cyclosporine derivatives are disclosed which possess enhanced efficacy and reduced toxicity over naturally occurring and other presently known cyclosporins and cyclosporine derivatives. The cyclosporine derivatives of the present invention are produced by chemical and isotopic substitution of the cyclosporine A (CsA) molecule by: (1) Chemical substitution and optionally deuterium substitution of amino acid 1; and (2) deuterium substitution at key sites of metabolism of the cyclosporine A molecule such as amino acids 1, 4, 9. Also disclosed are methods of producing the cyclosporine derivatives and method of producing immunosuppression with reduced toxicity with the disclosed cyclosporine derivatives.