My 2 top endometriosis supplements

When it comes to managing endometriosis, many women are told their only options are surgery, the pill, or strong medications. While these can play a role and can make a huge difference in quality of life for some people, research shows there are also supplements that can support your body, reduce symptoms and pain, and improve overall quality of life.

Two of favourite supplements that I prescribe 95% of the time and stand out in both clinical practice and research are fish oil (omega-3 fatty acids) and N-acetyl cysteine (NAC).

1. A good quality fish oil

Fish oil is rich in omega-3 fatty acids, especially EPA and DHA, which have strong anti-inflammatory properties. Since endometriosis is an inflammatory condition, omega-3s can help calm the overactive inflammatory pathways driving pain and progression.

What the research says:

• Studies show omega-3s can reduce pelvic pain and even slow the development of endometriotic lesions in experimental models.

• Higher omega-3 intake is linked with less severe endo symptoms and improved fertility outcomes.

How it helps:

• Decreases inflammation that fuels endo pain.

• Supports hormone balance by competing with pro-inflammatory omega-6s.

• Improves fertility by supporting egg and embryo quality.

Aiming for a combined EPA/DHA dose of 2-3g is a great therapeutic dose for endo. It is important to take fish oil with a fat source to improve absorption. Keeping fish oil in the fridge is a good option to reduce rancidity.

2. NAC

N-acetyl cysteine (NAC) is a form of the amino acid cysteine and a powerful antioxidant. It supports your body’s production of glutathione, often called the “master antioxidant.” This matters because oxidative stress and inflammation are strongly linked with endometriosis progression and symptom severity.

What the research says:

• A 2013 Italian clinical trial found that women with endometriosis who took NAC had a significant reduction in endometrioma size and pain compared to those who didn’t supplement. Some even avoided surgery because of the improvements.

• A 2023 systematic review found NAC supplementation was linked with reduced endometrioma size, improvements in pelvic pain, and higher spontaneous pregnancy rates.

How it helps:

• Reduces pelvic pain and endometrioma size.

• Lowers oxidative stress and inflammation.

Quality & Dose Matter

It’s not just about taking a supplement, it’s about taking the right kind and in the right dose.

• Fish oil: Always choose a high-quality, practitioner-grade product that has been screened for heavy metals, PCBs, and other environmental contaminants. Many supermarket brands don’t undergo this level of testing. Look for high EPA/DHA content per capsule so you can achieve therapeutic doses without swallowing a handful each day (2-3g combined EPA/DHA dose).

• NAC: Evidence-based benefits are seen at therapeutic doses (typically in the range of 600–1800mg daily). Lower doses may not provide the same effects.

When dosed correctly and chosen carefully, these supplements can have a real, measurable impact on endometriosis symptoms and overall wellbeing.

Research:

• Porpora et al., 2013 (Italy):
  In a prospective clinical trial, 92 women with endometriomas were given either NAC (600 mg, three times daily, 3 consecutive days per week for 3 months) or no treatment.

  • Results: 24 patients in the NAC group cancelled planned surgery due to disappearance or reduction of cysts, pain improvement, or pregnancy. Endometriomas decreased in size in the NAC group, while they increased in size in the untreated group.

  • Reference: Porpora MG, et al. A promise in the treatment of endometriosis: an observational cohort study on ovarian endometrioma reduction by N-acetylcysteine. Evid Based Complement Alternat Med. 2013. doi: 10.1155/2013/240702

• Anastasi et al., 2023:
  This study followed 120 women aged 18–45 with endometriosis, who took oral NAC (600 mg, 3 tablets/day for 3 consecutive days each week, over 3 months). Key outcomes - less pain, less use of NSAID needed, significant reduction in cyst size seen on ultrasound, reduced inflammatory markers (Ca125), improved fertility outcomes.

  • Reference: Anastasi E, et al. Efficacy of N-Acetylcysteine on Endometriosis-Related Pain, Size Reduction of Ovarian Endometriomas, and Fertility Outcomes. Int J Environ Res Public Health. 2023 Mar 7;20(6):4686. doi: 10.3390/ijerph20064686

• Missmer et al., 2010 (Nurses’ Health Study II):
  Higher intake of long-chain omega-3 fatty acids was associated with a significantly lower risk of laparoscopically confirmed endometriosis.

  • Reference: Missmer SA, et al. A prospective study of dietary fat consumption and endometriosis risk. Hum Reprod. 2010;25(6):1528–35.

• Experimental models (rats/mice):
  Omega-3 supplementation has been shown to reduce the growth of endometriotic lesions and lower inflammatory markers.

  • Reference: Netsu S, et al. Oral eicosapentaenoic acid supplementation reduces the size of endometriotic implants in rats. Fertil Steril. 2008;90(5 Suppl):1496–502.

• Clinical pain outcomes:
  Omega-3 supplementation has been linked to reduced menstrual pain/dysmenorrhea, which often overlaps with endometriosis-related pain.

  • Reference: Rahbar et al.. Effect of omega-3 fatty acids on intensity of primary dysmenorrhea. Int J Gynaecol Obstet. 2012 Apr;117(1):45-7. doi: 10.1016/j.ijgo.2011.11.019.