Possibly not. I have not had any issues with vitamin overload. Trust me my chubby Grif is no where near malnurished. It would be like giving him a multivitamin dose. You can use less than directed by the dosage/weight guide. It is worth a try. If you are worried about the overload problem you can skip a couple doses of your normal dustings. The Repta-Aid contains fiber among other vitamines and minerals. The only other thing is Laxatives, but with out a vet to give proper dosage I wouldn't recomend it. I really hope he passes the impaction.