N-Acetyl Cysteine for PCOS Egg Quality and Healthy Ovaries

N-Acetyl Cysteine has been studied for the treatment of PCOS for the past several years and is one of my favourite supportive nutrients. I take it myself, and recommend it often to my patients. A new study has just been released which looked into the use of N-Acetyl Cysteine for embryo and egg quality in IVF cycles, as a possible alternative to Metformin.

As is well-known, insulin resistance is a central aggravating feature of PCOS. When women with PCOS undergo IVF, they often produce more than the average number of eggs for their age bracket (a good thing!), however many of these eggs are of low quality (not such a good thing!). It has been thought that this is related in part to the insulin resistance present during their IVF cycle. The same likely rings true for those trying to conceive without medication – quality, not quantity is key if you have PCOS. Good quality eggs promote healthy ovulation, so for women with PCOS who are not actively trying to conceive, healthy ovaries are very important.

What is NAC?

N-Acetyl Cysteine is an amino-acid derivative with 40 years of scientific validation standing strong behind it. NAC has already been shown to improve insulin sensitivity for women with PCOS (1) and is considered to be safe and well-tolerated overall. I’ve been using it for many years in my practice for hundreds of women with PCOS with very good success rates. Side effects are rare, and when they do occur, they are usually digestive. I myself have experienced heartburn from taking NAC, so I always take it with food.

What can NAC do for my Ovaries?

NAC can increase ovulation rates in patients with anovulatory PCOS (2) and help women with PCOS who are resistant to clomid (3). In addition to these wonderful benefits, NAC can also increase our cellular glutathione levels (4), protecting egg quality and health by improving the length of the egg’s telomeres(5). What are telomeres, you ask? Telomeres are the special buffers that reside at the ends of our chromosomes. Similar to the plastic tips of a shoelace that protect the shoelace from fraying, they protect our DNA from damage and are associated with longevity and health – cool, right?. In addition to providing all of these great benefits, NAC also has a potent anti-inflammatory effect(6) which we know is extremely helpful as inflammatory factors are present in the vast majority of women with PCOS.

Comparison of NAC to Metformin

This study (7) followed 3 groups of patients. Group 1 was treated with placebo, group two was treated with metformin dosed at 500mg three times daily, and group 3 was treated with NAC at a dose of 600mg three times daily and group 4 was treated with a combination of NAC at 600mg three times daily and metformin at 500mg three times daily. All treatments were administered for 6 weeks and then patients underwent IVF treatment.

Firstly I just want to explain why it’s interesting that IVF was used in this study. IVF is an excellent way to objectively gauge impact on egg quality as can quantify the quality of the eggs and embryos produced by a woman. In IVF, the eggs are removed and can be analyzed in the lab to identify various characteristics that are linked to quality. This is why this study is so very interesting when it comes to identifying whether or not NAC is truly biologically effective for egg quality in women with PCOS.


The number of good (Grade 1) Embryos formed on day 3 after retrieval increased in only the NAC-treated group and not in the groups including Metformin or placebo. Looking at the internal microscopic elements of the eggs retrieved, there was improved composition of various cellular parts of the eggs retrieved including less fragmentation of the polar bodies in the NAC treated group of women. The objective “egg quality” markers in the NAC-treated group indicated significant improvement in the womens’ ovarian cell health.


Overall this study helps us to identify just how NAC can help women with PCOS who would like to conceive but also goes far beyond to overall ovary health. NAC is a protector of the ovary in the face of insulin resistance, and improves egg and embryo quality. Women with PCOS, though we may be fortunate enough to have plenty of eggs, often struggle with poor egg quality which can lead to subfertility and increased risk of miscarriage. NAC has minimal side effects and an excellent safety track record. Even for those women with PCOS who are not trying to conceive, NAC has proven to be a beneficial natural therapeutic to help regulate ovulation.

Do you have questions about N-Acetyl Cysteine? Have you tried it? What were your results? Leave your comments below!


  1. Fulghesu, A. M., Ciampelli, M., Muzj, G., Belosi, C., Selvaggi, L., Ayala, G.F., and Lanzone, A. (2002). N-Acetyl-cysteine treatment improves insulin sensitivity in women with polycystic ovary syndrome. Fertil Steril. 77, 1128–1135.
  2. Badawy, A., and Abdelgawad, S. (2007). N-Acetyl cysteine and clomiphene citrate for induction of ovulation in polycystic ovary syndrome: a crossover trial. Acta Obstet. Gynecol. Scand. 86, 218–222.
  3. Elnashar, A., Fahmy, M., Mansour, A., and Ibrahim, K. (2007). N-acetyl cysteine vs. metformin in treatment of clomiphene citrate–resistant polycystic ovary syndrome: a prospective randomized controlled study. Fertil. Steril. 88(2), 406–409
  4. De Rosa, S. C., Zaretsky, M. D., Dubs, J. G., Roederer, M., Anderson, M., Green, A., Mitra, D., Watanabe, N., Nakamura, H., Tjioe, I., Deresinski, S. C., Moore, W. A., Ela, S. W., Parks, D., Herzenberg, L. A., and Herzenberg, L. A. (2000). N-Acetylcysteine replenishes glutathione in HIV infection. Eur. J. Clin. Invest. 30, 915–929.
  5. Liu, J., Liu, M., Ye, X., Liu, K., Huang, J., Wang, L., Ji, G., Liu, N., Tang, X., and Baltz, J. M. (2012). Delay in oocyte aging in mice by the antioxidan N-acetyl-L-cysteine (NAC). Hum. Reprod. 27, 1411–1420
  6. Hou Y, Wang L, Yi D, Ding B, Yang Z, Li J, Chen X, Qiu Y, Wu G. N-acetylcysteine reduces inflammation in the small intestine by regulating redox, EGF and TLR4 signaling. Amino Acids. 2013 Sep;45(3):513-22.
  7. Cheraghi E, Mehranjani MS, Shariatzadeh MA, Esfahani MH, Ebrahimi Z. N-Acetylcysteine improves oocyte and embryo quality in polycystic ovary syndrome patients undergoing intracytoplasmic sperm injection: an alternative to metformin. Reprod Fertil Dev. 2014 Nov 13.