Endometriosis
Supplements studied for endometriosis.
Overview
Garlic tablets (WA 56, one study) reported a 72% pain reduction over three months versus placebo when added to standard care, across pelvic, menstrual, and intercourse pain. Melatonin (WA 48; low effect size, medium evidence, medium trust) at 10 mg daily for eight weeks reduced pain and analgesic use in some trials, but 20 mg daily showed no clear benefit.
Vitamin D (WA 40; very low effect size, high evidence, medium trust) showed no meaningful benefit. Milk Thistle and N-Acetyl Cysteine (NAC) have uncertain effects from small or combination-product studies. The heatmap and evidence reviews below cover all five supplements.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Garlic | ★★★★★ | Medium |
| Milk Thistle | ★★★★★ | Low |
| Melatonin | ★★★★★ | Low |
| Vitamin D | ★★★★★ | Very Low / None |
| N-Acetyl Cysteine (NAC) | ★★★★★ | Low |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
5 supplements for rated at least stars. All purchase bands. No minimum star filter.
GarlicView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- A clinical study showed that women with endometriosis who took a garlic tablet every day for 3 months experienced a 72% reduction in their overall pain compared to a slight increase in pain in those who took a placebo.
- Garlic helped relieve different types of pain like pelvic pain, back pain, menstrual cramps, and pain during intercourse when used with standard treatment.
Browse 1 study
RCTThe Effect of Garlic Tablets on the Endometriosis-Related Pains: A Randomized Placebo-Controlled Clinical Trial2021n=60
In 60 women with endometriosis, 400 mg/day garlic tablets for two menstrual cycles significantly reduced pelvic pain, dysmenorrhea, and dyspareunia on visual analogue scales versus placebo.
- Effect
- Benefit
- Dose
- 400 mg/day
- Population
- Women
- Participants
- 60
- Ages
- 20–45
MelatoninView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Early studies show that taking 10 mg of melatonin daily for 8 weeks can reduce pain and the need for pain medications in women with endometriosis, including pain during periods and sex.
- But other studies using a higher dose of 20 mg daily have not found clear benefits.
- More research is needed.
Browse 3 studies·1 meta-analysis
RCTThe effect of antioxidant supplementation on dysmenorrhea and endometriosis-associated painful symptoms: a systematic review and meta-analysis of randomized clinical trials2024
A meta-analysis of 10 antioxidant RCTs found antioxidant supplements including melatonin significantly reduced dysmenorrhea severity (SMD −0.48) and endometriosis-related pelvic pain.
- Effect
- Benefit
RCTAdjuvant use of melatonin for pain management in endometriosis-associated pelvic pain—A randomized double-blinded, placebo-controlled trial2023n=40
In 40 women with endometriosis, 20 mg melatonin daily for two menstrual cycles significantly reduced pelvic pain and dysmenorrhea on an 11-point scale versus placebo.
- Effect
- No Benefit
- Dose
- 20 mg/day
- Population
- Women
- Participants
- 40
- Ages
- 18–50
RCTEfficacy of melatonin in the treatment of endometriosis: a phase II, randomized, double-blind, placebo-controlled trial2013n=20
In 40 women with endometriosis, 10 mg melatonin nightly for 8 weeks significantly reduced chronic pelvic pain, dysmenorrhea, dysuria, and daily analgesic use versus placebo.
- Effect
- Benefit
- Dose
- 10 mg
- Population
- Women
- Participants
- 20
- Ages
- 18–45
Milk ThistleView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It isn’t clear if milk thistle helps with endometriosis.
- In one study, women who took milk thistle twice a day for 12 weeks had less pain, but there was no improvement in sexual function.
- Some experts caution against using milk thistle in endometriosis because it may act like estrogen in the body.
Browse 3 studies
RCTA randomized trial assessing the efficacy of Silymarin on endometrioma-related manifestations2022n=70
A 12-week double-blind RCT of 70 women with endometriosis found 140 mg/day silymarin reduced endometrioma volume, IL-6, pain, and improved quality of life versus placebo.
- Effect
- Benefit
- Duration
- 12 weeks
- Dose
- 140 mg/day
- Population
- Women
- Participants
- 70
- Ages
- 15–49
Evidences for antiosteoporotic and selective estrogen receptor modulator activity of silymarin compared with ethinylestradiol in ovariectomized rats2010
An ovariectomized rat study found silymarin improved bone density and acted as a selective estrogen receptor modulator without uterine stimulation.
- Effect
- Benefit
- Duration
- 12 weeks
Silymarin is a selective estrogen receptor beta (ERbeta) agonist and has estrogenic effects in the metaphysis of the femur but no or antiestrogenic effects in the uterus of ovariectomized (ovx) rats2003
An experimental rat study found silymarin selectively activated ERβ, improving bone parameters without stimulating uterine tissue.
- Effect
- Benefit
- Population
- Adults
N-Acetyl Cysteine (NAC)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if N-acetylcysteine (NAC) alone helps with endometriosis pain.
- One small study found that taking a combination of NAC with other ingredients for 6 months lessened pain and the need for pain medicine compared to baseline.
Browse 2 studies
RCTEfficacy of N-Acetylcysteine on Endometriosis-Related Pain, Size Reduction of Ovarian Endometriomas, and Fertility Outcomes2023n=20
A 3-month RCT of 20 endometriosis patients found 1800 mg/day NAC reduced pain, endometrioma size, and improved quality of life versus placebo.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 1800 mg/day
- Population
- Pregnant women
- Participants
- 20
- Ages
- 18–45
Open-labelEffectiveness of an antioxidant preparation with N-acetyl cysteine, alpha lipoic acid and bromelain in the treatment of endometriosis-associated pelvic pain: LEAP study2018n=398
An open-label study of 398 adults found an antioxidant preparation with NAC improved metabolic and oxidative stress markers versus baseline.
- Effect
- Benefit
- Duration
- 3 months
- Population
- Women
- Participants
- 398
- Avg age
- ~35
Vitamin DView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Vitamin D has no meaningful benefit for Endometriosis.
Browse 3 studies
Systematic reviewVitamin D for primary dysmenorrhea and endometriosis-related pain - A systematic review of registered RCTs2025n=308
A systematic review of 7 registered RCTs (308 participants) found vitamin D may reduce primary dysmenorrhea pain severity on visual analog scale (MD −1.12), but evidence certainty was low and endometriosis results were null.
- Effect
- No Benefit
- Duration
- 2 months
- Dose
- 1000 IU/day
- Population
- Adults
- Participants
- 308
- Ages
- 18–50
RCTSupplementation with vitamin D or ω-3 fatty acids in adolescent girls and young women with endometriosis (SAGE): a double-blind, randomized, placebo-controlled trial2020n=147
In a 6-month RCT of 69 young women with endometriosis, 2,000 IU/day vitamin D3 reduced pelvic pain similarly to placebo; fish oil showed smaller pain reduction than either group.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 2000 IU/day
- Population
- Women
- Participants
- 147
- Ages
- 12–25
RCTEffects of Vitamin D on Endometriosis-Related Pain: A Double-Blind Clinical Trial2016n=19
A double-blind RCT of 39 women post-endometriosis surgery found 50,000 IU/week vitamin D for 12 weeks did not significantly reduce dysmenorrhea or pelvic pain versus placebo at 24 weeks.
- Effect
- No Benefit
- Duration
- 12 weeks
- Dose
- 50,000 IU vitamin D/week
- Population
- Women
- Participants
- 19
- Ages
- 15–40
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Melatonin | ★★★★★48% | 3 | 1 | 25% |
| Milk Thistle | ★★★★★48% | 3 | 0 | 25% |
| Vitamin D | ★★★★★40% | 3 | 0 | 25% |
| N-Acetyl Cysteine (NAC) | ★★★★★40% | 2 | 0 | 17% |
| Garlic | ★★★★★56% | 1 | 0 | 8% |