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Dr. Tori Hudson, Portland, Oregon, Blog Healthline Blog

uterine painEndometriosis is one of the most common gynecological diseases and can cause chronic pelvic pain and chronic lower abdominal pain, menstrual cramps, pain with vaginal penetration during sex, abnormal bleeding and infertility. Available conventional therapies include hormonal therapies, pain medication and surgery. A natural substance that is free of side effects, and one that shows efficacy would be a very appealing option. A well known supplement, N-acetylcysteine (NAC), which is the acetylated form of the amino acid cysteine, occurs naturally in some substances such as garlic.

This observational cohort study was designed to compare the progression of ovarian endometriomas in N-acetyl cysteine (NAC) treatment patients and untreated control patients. Patients were given either NAC 600 mg three times daily, 3 consecutive days per week or not, for an observation period of 3 months. At the end of the 3 month observation period, endometriomas (ovarian cysts or chocolate cysts related to endometriosis), were evaluated by pelvic ultrasound, by a trained physician, who was blinded as to which group the patients had been in.

A total of 92 Italian women, 47 in the NAC treated group and 45 in the untreated group were ultimately included. Women were enrolled to select inclusion criteria: 1) an ultrasound diagnosis of ovarian endometrioma 2) no hormonal treatment in the previous 2 months 3) laparoscopic surgery scheduled due to the presence of either a large endometrioma 30 mm or greater, pain or infertility.

In the NAC treated group, 24 patients cancelled their scheduled laparoscopy due to a decrease or disappearance of cysts, pain reduction or pregnancy. Again, in the NAC treated group, 14 women had decreased ovarian cysts (-1.5 mm average), 8 had a complete disappearance, 21 had pain reduction and 1 became pregnant. In the control group, only 1 patient cancelled surgery. There were 4 endometriomas that disappeared. Overall, more cysts reduced and fewer cysts increased in size in the NAC group. There were 4 newly formed cysts in the NAC group vs. 4 in the untreated group. After the observation period, a total of 8 pregnancies occurred in the NAC treated group and 6 in the untreated group.

Commentary: Up to 10% of reproductive aged women have endometriosis. In women with infertility, the numbers may be as high as 50%. The results of this study are impressive and actually compares to the results reported in a randomized placebo controlled study on 100 women treated for 4 months with oral contraceptives. In addition, there was one pregnancy during the study period and more after, which is of course a contrast with women who stay on oral contraceptives to manage their endometriosis. NAC does not negatively affect fertility, and if one looks to other research on insulin resistance and PCOS, we will find that NAC improves ovulation and thus fertility, similar to metformin, in PCOS patients. Previous evidence shows that NAC modulates the pathogenesis of endometriosis via several pathways. NAC decreases abnormal cell proliferation, decreases the invasive behavior of the endometriosis cells, decreases inflammatory substances, regulates expression of inflammation related genes, and stimulates cell differentiation. I will be interested in using NAC for not only treatment of current endometriomas, as well as endometriosis, as well as prevention of recurrence after a surgery.


Porpora M, Brunelli R, Costa G, et al. A promise in the treatment of endometriosis: an observational cohort study on ovarian endometrioma reduction by N-acetylcysteine. Evidence-Based Complementary and Alternative Medicine. 2013; April. Article ID 240702, 7 pages

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