For the exposure data, we used the GWAS results for glutamine (met-d-Gln) including 114,750 participants; testosterone (ebi-a-GCST90012114) including 425,097 participants; citrulline (met-a-356) including 7,773 participants; and lactate (met-d-Lactate) including 114,802 participants. The outcome data were derived from the GWAS results for myasthenia gravis (ebi-a-GCST90018876) including 355,142 participants, and late-onset myasthenia gravis (ebi-a-GCST90093466) including 34,930 participants. All of the above data were obtained from publicly available databases, ensuring compliance with ethical guidelines and data protection regulations.