Background: Ovarian reserve reflecting a woman's reproductive potential, naturally declines with age, impacting fertility. Various biomarkers, including anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH), estradiol (E2), and antral follicle count (AFC), are used to assess ovarian reserve. Dehydroepiandrosterone (DHEA) supplementation has been proposed to improve ovarian function in women with diminished ovarian reserve. This study aims to evaluate the effect of 12 weeks of DHEA supplementation on ovarian reserve markers in women with poor ovarian reserve, comparing it with a placebo group receiving folic acid. Methods: This randomized controlled study included 100 women aged 20-40 years with diminished ovarian reserve, diagnosed by low AMH, reduced AFC, and elevated FSH levels. The participants were divided into two equal groups: case group receiving DHEA (75 mg/day) and control group receiving folic acid (placebo) 5 mg/day for 12 weeks. Ovarian reserve was assessed by measuring AMH, FSH, LH, E2, AFC, and ovarian volume. Results: After 12 weeks, DHEA significantly increased AMH (1.24 ± 0.78 vs 0.85 ± 0.75, p = 0.012) and E2 (278.50 ± 135.80 vs 160.67 ± 116.90, p < 0.001), while decreasing FSH (9.07 ± 5.53 vs 11.87 ± 5.29, p = 0.011). DHEA also significantly increased AFC (4.1 vs 3.47, p < 0.05). Conclusion: DHEA supplementation significantly improves ovarian reserve markers, including AMH, E2, FSH, and AFC, in women with diminished ovarian reserve, supporting its use as a potential therapeutic option in this population.