Insulin injection should be disinfected with 75% medical alcohol. Since insulin is a protein-like substance, the amino acid will be denatured when it meets iodine, which will make insulin inactive and affect the dose and efficacy. Note that after disinfection, you should wait for the alcohol to dry before subcutaneous injection to prevent irritation at the injection site. The skin should be disinfected before each injection, and the injection should be pushed slowly, and the needle tip should stay in the subcutaneous tissue for 10-15S after the injection is completed, so that the insulin can be fully absorbed. Be careful not to disinfect the needle with alcohol to avoid damaging the protective film of the needle and causing pain at the injection site.