In this study, the effects of L carnitine on clinical symptoms, lipid profile and oxidative stress in women with osteoarthritis, was investigated. The design of study is a double-blind randomized clinical trial. In this clinical trial, 76 women with osteoarthritis will be randomly assigned to 2 groups by using the table of random numbers: 1) Consuming one tablet 1000 mg L carnitine AND weight loss diet 2) Consuming one tablet placebo with weight loss diet. Inclusion criteria will include women between 45- 70 years, body mass index(BMI) more than 25 and exclusion criteria will include disease such as heart disease, hypothyroidism, rheumatoid arthritis , hepatic disease, kidney disease. Participants will be followed up for 12 weeks. Total cholesterol, triglyceride, high density lipoprotein cholesterol, C reactive protein(CRP), Malondialdehyde (MDA), weight, height, fat mass, fat free mass, waist, Hip circumference, Western Ontario and McMaster Universities Arthritis Index(WOMAC)(for pain) will be measured at the baseline and at the end of the trial. Low density lipoprotein level will be calculated by the Friedewald's formula.