Aging and sex hormones significantly influences on metabolic profiles, particularly in individuals aged 50 year and older. This study aimed to investigate the associations between serum metabolites, aging, and sex hormone levels among elderly individuals in Bushehr, Iran - a coastal region characterized by a unique lifestyle, dietary patterns, and environmental conditions, such as high seafood consumption and exposure to marine climate, which may collectively influence metabolic profiles and hormone levels in the aging population.This cross-sectional study analyzed data from the Bushehr Elderly Health Program, which included 2001 participants (1143 women and 858 men) aged over 50 years old from Bushehr, Iran. Serum levels of 20 amino acids were measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the results were analyzed based on gender, age, menopause status, menopause age, and serum levels of sex hormones such as follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone, and estradiol (E2). Statistical analyses were performed using SPSS version 25.0 and R version 4.0.3, with a focus on gender differences and the correlation between aging, sex hormones, and metabolite profiles.

 Among the 2001 participants, mean ages were 61.57 ± 7.6 years for women and 62.92 ± 8.4 years for men. Men had higher serum levels of glutamic acid, leucine, methionine, phenylalanine, tyrosine, valine, citrulline, ornithine, proline, threonine, histidine, lysine, tryptophan, asparagine, and glutamine, while women had higher levels of glycine and serine. Aging was associated with notable changes in amino acid levels, such as increased citrulline and decreased threonine in women, and similar trends in men with a pronounced decrease in alanine. In men, low testosterone levels were linked to reduced concentration of alanine, methionine, phenylalanine, tyrosine, citrulline, glycine ornithine, serine, lysine, asparagine, and glutamine. Postmenopausal women showed a significant decrease in threonine levels.