N-ACETYL CYSTEINE: A Natural Insulin-Sensitizer for PCOS?
New research shows women with PCOS who have insulin resistance may benefit from taking the nutritional supplement N-Acetyl Cysteine, also known as NAC.
NAC is both an antioxidant and amino acid (building blocks of protein). Specifially, NAC is a derivative of the amino acid L-cysteine, an essential precursor used by the body to produce glutathione. Glutathione is an extremely important and powerful antioxidant produced by the body to help protect against free radical damage, and is a critical factor in supporting a healthy immune system. NAC is widely sold in Europe as a treatment for the common cold and it has other numerous uses from being a treatment for bronchitis to removing heavy metals and environmental pollutants from the body. NAC has also been found to reduce inflammation, heart disease and most recently, insulin.
PCOS & N-ACETYL CYSTEINE
Only a handful of studies have examined the benefits of NAC in women with PCOS. The most recent study, published in the European Journal of Obstetrics, Gynecology and Reproductive Biology compared the effects of NAC and metformin on insulin levels. In this prospective trial, 100 women with PCOS were divided to receive metformin (500mg three times daily) or NAC (600mg three times daily) for 24 weeks. The results: Both treatments resulted in a significant decrease in body mass index, hirsutism, fasting insulin, free testosterone and menstrual irregularity, and both treatments had equal effectiveness. Furthermore, NAC led to a significant decrease in both total cholesterol and low-density lipoprotein levels, whereas metformin only led to a decrease in total cholesterol level.
This research supports findings published in the Journal of Fertility and Sterility in 2002 where researchers reported significant improvement in insulin levels among women with PCOS who took 1.6-3g/day of NAC and who had elevated insulin levels before the start of study. Women also showed improvements in testosterone, cholesterol and TG levels.
In regards to fertility, when NAC and clomid was compared with metformin and clomid, the metformin-clomid group had more ovulation and a better chance at achieving pregnancy among women with PCOS.
Overall, NAC is well tolerated but can cause gastrointestinal adverse effects including nausea, abdominal pain, vomiting, constipation, and diarrhea, particularly when used in high doses. The therapeutic dosage of NAC to improve insulin levels based on the published studies is 1.6-3 grams/day. If you are overweight, you may benefit from the higher end of the dose range. Fulghesu et al found that obese patients with PCOS did not respond to doses under 3 grams/day. You should not exceed 7grams/daily. As with any nutrition supplement, it is important to discuss use with your physician before taking.
Bottom line: NAC has been shown to improve menstrual regularity but has not been shown to help improve fertility in women with PCOS. NAC may help improve insulin resistance in women with PCOS who have high insulin levels and could be used with metformin or if metformin isn't an option. NAC also seems to have a favorable effect of lowering cholesterol, TG and testosterone. Long-term studies with NAC are needed. It would be interesting to determine the effects of taking NAC in combination with metformin or other supplements proven to improve to improve insulin in women with PCOS.
We want to hear from you: What has been your experience with NAC?
Fulghesu AM, Ciampelli M, Muzj G, Belosi C, Selvaggi L, Ayala GF, Lanzone A. N-acetyl-cysteine treatment improves insulin sensitivity in women with polycystic ovary syndrome. Fertil Steril. 2002 Jun;77(6):1128-35.
Abu Hashim H, Anwar K, El-Fatah RA. N-acetyl cysteine plus clomiphene citrate versus metformin and clomiphene citrate in treatment of clomiphene-resistant polycystic ovary syndrome: a randomized controlled trial. J Womens Health (Larchmt). 2010 Nov;19(11):2043-8. Epub 2010 Oct 12.
Oner G, Muderris II. Clinical, endocrine and metabolic effects of metformin vs N-acetyl-cysteine in women with polycystic ovary syndrome. Eur J Obstet Gynecol Reprod Biol. 2011 Aug 8.