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Endometriosis

Everything in the library studied for it, medical and holistic together. Within each kind, what was shown to help comes first, strongest evidence first. What was tested and not shown to help stays on the list.

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Medication7 Supplements2 Therapies8 Practices2 Daily life1 Lab markers8 On a blood test

Medication

Progestins for endometriosis and heavy bleedingStrongStudied in women

Endometriosis pain, compared with placebo

Shown to ease pain in women with endometriosis against placebo, by 2.58 points on a visual analogue pain scale for oral progestins in pooled trials.

Compared with placebo or no treatment, pooled together [5]; placebo [6][7][8]

The numbers and sources

Effect: Against placebo or no treatment, oral progestins lowered overall pain at six months (MD -2.58, 95% CI -3.13 to -2.03, moderate certainty) and period pain at three months (RR 0.21, 95% CI 0.07 to 0.70), while pelvic pain at three months did not differ (RR 0.7, 95% CI 0.29 to 1.69). Quality of life rose (SF-36 MD 4.11, 95% CI 2.41 to 5.82, high certainty) [5]. A network meta-analysis found dienogest superior to placebo for pelvic pain outside periods and for pain during sex [6]. In a 12-week placebo-controlled trial, pain on a 100 mm scale fell 27.4 mm with dienogest 2 mg and 15.1 mm with placebo, a difference of 12.3 mm [7]. In a 24-week trial in China, the difference was 24.54 mm (95% CI 19.15 to 29.93) [8].
Population: 8 trials of oral progestins against placebo or no treatment, within a review of 33 trials and 5,059 women with endometriosis confirmed at laparoscopy [5]. 3,259 women in 8 trials [6]. 198 women aged 18 to 45 in Germany, Italy and Ukraine [7]. 255 Chinese women aged 18 to 45 [8].
Sources: [5], [6], [7], [8]
Caveats: The Cochrane comparison pools placebo and no-treatment arms, so it mixes a blinded comparison with an unblinded one [5]. Pain fell 15.1 mm on placebo alone in the 12-week trial [7]. The review notes that few trials report each outcome [5].

Hormonal birth controlModerateStudied in women

Endometriosis pain (combined pill)

Shown to ease endometriosis period pain more than placebo in two small trials, in very low-quality evidence. Pain at 6 months matched goserelin in one trial.

Compared with placebo [32][33]; goserelin [32]; oral progestins and GnRH agonists [33]

The numbers and sources

Effect: Against placebo, combined pills lowered period pain on a visual analogue scale (MD -23.68 points, 95% CI -28.75 to -18.62, 2 RCTs, 327 women) and on a 0 to 3 verbal scale (MD -1.30, 95% CI -1.84 to -0.76, 1 RCT, 96 women). At 6 months, pain did not differ from goserelin (MD -0.10 on a 1 to 10 scale, 95% CI -1.28 to 1.08, 50 women) [32]. A review of 9 RCTs and 9 observational studies found combined hormonal contraceptives lowered period pain, pelvic pain and pain with sex from baseline in most studies, about as much as or less than oral progestins and GnRH agonists [33].
Population: 612 women with surgically confirmed endometriosis in 5 trials, 404 analyzed [32]; women with endometriosis in 18 studies [33].
Sources: [32], [33]
Caveats: Both placebo trials were at high risk of bias, with substantial involvement of the drug company that funded them [32]. Only 2 of the 9 trials in [33] were placebo-controlled, and most were not blinded.

Progestins for endometriosis and heavy bleedingModerateStudied in women

Endometriosis pain, compared with GnRH agonist injections

Shown to ease endometriosis pain in women about as much as GnRH agonist injections such as leuprolide, with less bone loss and fewer hot flushes.

Compared with GnRH agonists [5]; leuprolide injections [9][10][11][1]; a GnRH antagonist [5]

The numbers and sources

Effect: Oral progestins and GnRH agonists did not differ for overall pain (MD -0.01, 95% CI -0.30 to 0.28, low certainty), and side effects overall were more frequent with oral progestins (RR 1.44, 95% CI 1.11 to 1.86). Depot progestins reduced period pain slightly more than GnRH agonists (RR 0.93, 95% CI 0.89 to 0.97, high certainty) with fewer side effects overall (RR 0.03, 95% CI 0.01 to 0.11). Against a GnRH antagonist, more women stopped a depot progestin for side effects (RR 2.02, 95% CI 1.04 to 3.94) [5]. Over 24 weeks, pain fell 47.5 mm with dienogest and 46.0 mm with leuprolide, and spine bone density changed +0.25% against -4.04% [9]. The medroxyprogesterone injection matched leuprolide on four of five pain signs at 6 months and all five at 18 months, with less bone loss [10][11]. Moderate or severe hot flushes at month 6 were reported by 27% on the injection and 69% on leuprolide [1].
Population: 10 trials of oral progestins and 2 of depot progestins against GnRH agonists [5]. 252 women [9]. 274 women in Canada and the US [10]. 300 women [11]. Women in the injection's two endometriosis trials [1].
Sources: [5], [9], [10], [11], [1]
Caveats: These are equivalence comparisons between two active drugs, not against placebo. The dienogest trial was open-label [9], and the injection trials blinded only the evaluator [10][11].

Hormonal birth controlLimitedStudied in women

Endometriosis pain after surgery (hormonal IUD)

Small trials found period pain fell more at 12 months with a hormonal IUD placed after endometriosis surgery than with no further treatment, at low certainty.

Compared with expectant management after surgery [34]

The numbers and sources

Effect: In one trial, the median fall in period pain on a visual analogue scale was 81 with the levonorgestrel IUD against 50 with no further treatment (P = 0.006, 55 women). In another, pain fell 50 points against 30 (P = 0.021, 40 women). The trials could not be pooled. Satisfaction was higher with the IUD, 75% against 50% in one trial [34].
Population: 157 women having surgery for endometriosis in 4 RCTs [34].
Sources: [34]
Caveats: Certainty was low to very low, from risk of bias and imprecision. No trial reported overall pain [34].

Progestins for endometriosis and heavy bleedingLimitedStudied in women

Endometriosis pain: norethindrone acetate compared with dienogest

One small trial found norethindrone acetate 5 mg and dienogest 2 mg eased endometriosis pain in women to a similar degree over 12 months, with fewer dropouts on norethindrone acetate.

Compared with dienogest [13]; dienogest, in consecutive patients before and after a clinic switched drugs [14]

The numbers and sources

Effect: Period pain scores fell from 7.43 and 7.23 to 0 in women completing 12 months on either drug, and pelvic pain scores did not differ significantly. Endometriomas shrank more on norethindrone acetate (p = 0.037). By 6 months, 47.5% on dienogest and 23.3% on norethindrone acetate had dropped out (p = 0.026) [13]. In a clinic that changed its first-choice drug, 71% on norethindrone acetate 2.5 mg and 72% on dienogest were satisfied or very satisfied at 6 months. Treatment was well tolerated by 58% and 80% [14].
Population: 70 women aged 18 to 40, 30 on norethindrone acetate and 40 on dienogest, in Turkey [13]. 90 consecutive women on each drug in Italy [14].
Sources: [13], [14]
Caveats: No placebo group. Scores at 12 months come from women who stayed on treatment [13]. The second study was not randomized [14].

Progestins for endometriosis and heavy bleedingModerateStudied in women

Endometriosis pain, compared with combined birth control pills

Mixed results: pooled trials found no clear difference in pelvic pain between progestin and combined birth control pills in women with endometriosis. Another review's results varied by pain type.

Compared with combined oral contraceptives [5][12]

The numbers and sources

Effect: Pelvic pain did not differ between oral progestins and combined pills (MD 0.38, 95% CI -0.46 to 1.22, moderate certainty), and side effects overall did not differ (RR 1.13, 95% CI 0.8 to 1.60). Pain-related quality of life was higher with progestins (SF-36 pain MD 11.5, 95% CI 2.35 to 20.65, low certainty) [5]. In another review of 8 trials, dienogest lowered overall pain scores more than a drospirenone pill (SMD -1.66, 95% CI -3.16 to -0.15), but eased pelvic pain (SMD 0.42) and pain during sex (SMD 0.70) less than combined pills. Side effects did not differ, except more hand numbness and weight gain on the pills [12].
Population: Women with endometriosis in 4 trials [5] and 8 trials [12].
Sources: [5], [12]
Caveats: Few small trials, and the certainty for most outcomes was low or very low [5].

NSAIDsLimitedStudied in women

Endometriosis pain

One small trial found naproxen did not clearly relieve endometriosis pain more than placebo, in very low-quality evidence.

Compared with placebo [26]

The numbers and sources

Effect: Pain relief on naproxen did not differ clearly from placebo (OR 3.27, 95% CI 0.61 to 17.69, 24 women). The need for extra pain medicine (OR 0.12, 95% CI 0.01 to 1.29) and side effects (OR 0.46, 95% CI 0.09 to 2.47) were inconclusive [26].
Population: 24 women with endometriosis in one crossover trial, the only one of two included trials that could be analyzed [26].
Sources: [26]
Caveats: One small trial with unclear risk of bias. The review found no new trials in its 2016 update, and no data on quality of life or daily activities [26].

Supplements

Vitamin EModerateStudied in women

Endometriosis pain, with vitamin C

Shown in pooled trials to ease pelvic pain, period pain and pain with sex in women with endometriosis when vitamin E was taken with vitamin C.

Compared with placebo [19][20][21]

The numbers and sources

Effect: Across 5 RCTs of vitamins C and E together, more women reported less chronic pelvic pain (RR 7.30, 95% CI 3.27 to 16.31), less period pain (RR 1.96, 95% CI 1.25 to 3.07) and less pain with sex (RR 5.08, 95% CI 2.10 to 12.26) than on placebo [19]. A review of 13 RCTs found vitamin E, with or without vitamin C, improved pelvic pain [20]. In one trial, 1,200 IU of vitamin E with 1,000 mg of vitamin C for 8 weeks improved everyday pain in 43% of women (P = 0.0055), with no change on placebo, and period pain fell in 37% [21].
Population: 5 RCTs in women with endometriosis [19]; 13 RCTs with 589 women [20]; 59 women aged 19 to 41 with pelvic pain and endometriosis or infertility [21].
Sources: [19], [20], [21]
Caveats: Vitamin E was given with vitamin C, so its share of the effect is not separated. Trials were small and lasted about 8 weeks. The second review's abstract gives no pooled size for vitamin E [20].

Vitamin DModerateStudied in women

Endometriosis pain

Mixed results: three reviews found no significant drop in endometriosis pain on vitamin D, while one found less period pain in its vitamin D trials.

Compared with placebo [64][65][66][67]

The numbers and sources

Effect: Pain did not fall significantly in the 3 trials of secondary dysmenorrhea [64] or in the registered endometriosis trials [65]. A review of 13 RCTs found vitamin D lowered pelvic pain in endometriosis, a difference that was not significant against placebo [66]. A review of antioxidant supplements found less endometriosis-related period pain in the vitamin D trials (SMD -0.59, 95% CI -1.13 to -0.06, I² 70%) [67].
Population: 3 RCTs in secondary dysmenorrhea [64]; registered RCTs in endometriosis [65]; 13 RCTs with 589 women with endometriosis [66]; 10 RCTs of antioxidant supplements in endometriosis [67].
Sources: [64], [65], [66], [67]
Caveats: Trials were few and small, and heterogeneity was high [67].

Therapies

Endometriosis surgeryStrongStudied in womenVery common

Pregnancy in mild endometriosis, compared with diagnostic laparoscopy

Shown to raise pregnancy rates in women with minimal or mild endometriosis against diagnostic laparoscopy alone: 30.7% against 17.7% reached 20 weeks in the largest trial.

Compared with diagnostic laparoscopy alone [4][8]; placebo, as the network analysis names its comparison [9]

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: Surgery raised viable intrauterine pregnancy against diagnostic laparoscopy (OR 1.89, 95% CI 1.25 to 2.86, 3 trials, 528 women, moderate certainty). No trial in the review measured live birth [4]. In a Canadian trial, 50 of 172 women after resection or ablation and 29 of 169 after diagnostic laparoscopy had pregnancies lasting 20 weeks or more within 36 weeks (cumulative 30.7% against 17.7%, rate ratio 1.9, 95% CI 1.2 to 3.1). Fetal loss was 20.6% and 21.6% [8]. A network meta-analysis found higher odds of pregnancy after surgical laparoscopy than placebo (OR 1.63, 95% CI 1.13 to 2.35) [9].
Population: 528 women in 3 trials [4]. 341 infertile women aged 20 to 39 with minimal or mild endometriosis [8]. 2,245 women with endometriosis-related infertility in 26 trials [9].
Sources: [4], [8], [9]
Caveats: Live birth was not measured in the pooled trials [4]. These trials covered minimal or mild disease only.

Endometriosis surgeryModerateStudied in womenVery common

Endometriosis pain, compared with sham surgery

Shown to ease endometriosis pain in women more than a sham diagnostic laparoscopy in two small blinded trials, with 80% against 32% improved after excision.

Compared with diagnostic laparoscopy alone, with the women unaware of their group (sham surgery) [1][2][3][4]

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: Six months after surgery, 16 of 20 women (80%) reported improvement after full excision and 6 of 19 (32%) after a diagnostic procedure only. Quality of life improved after excision and not after the sham. About 20% did not improve after surgery [1]. In a second trial, 62.5% improved or were free of symptoms 6 months after laser ablation, against 22.6% after diagnostic laparoscopy alone, rising to 73.7% when only mild and moderate disease was counted. Results were poorest for minimal disease [2]. At 1 year, relief continued in 90% of those who first responded [3]. The Cochrane review rated pooled pain data against diagnostic laparoscopy very low in certainty (MD 0.90 at 6 months and 1.65 at 12 months on a pain relief scale, 1 trial of 16 women), and quality of life did not differ (EQ-5D MD 0.03, 95% CI -0.12 to 0.18) [4].
Population: 39 women with endometriosis of all stages, crossover design [1]. 63 women with minimal to moderate endometriosis and pain [2][3]. 14 trials and 1,563 women in the review [4].
Sources: [1], [2], [3], [4]
Caveats: Both sham-controlled trials were small. The laser trial also cut the uterine nerves [2]. About 30% improved after the sham alone, a placebo response the authors found was not tied to disease severity [1]. The Cochrane review notes unclear blinding and poor reporting across trials [4].

Endometriosis surgeryModerateStudied in women

Endometriomas: excision compared with drainage and ablation

Shown to lower pain and cyst recurrence in women with endometriomas against drainage and ablation. Endometriomas recurred in 5% to 17% after excision against 37% after ablation.

Compared with drainage and ablation of the cyst [10]

The numbers and sources

Effect: Up to two years after surgery, excision lowered the return of period pain (OR 0.25, 95% CI 0.12 to 0.52, 49% after ablation against 10% to 34% after excision) and of pain during sex (OR 0.09, 95% CI 0.03 to 0.22, 58% against 4% to 23%). At one year, endometriomas returned less often (OR 0.17, 95% CI 0.09 to 0.34) and fewer women needed more surgery (32% after ablation against 3% to 16%). Spontaneous pregnancy in the first year did not differ (OR 1.27, 95% CI 0.33 to 4.87) [10].
Population: 578 women of reproductive age with endometriomas of at least 3 cm in 9 trials [10].
Sources: [10]
Caveats: Low certainty, with no blinding and small numbers. No trial reported surgical complications other than conversion to open surgery [10].

Endometriosis surgeryModerateStudied in women

Hormonal suppression after surgery, compared with none

Shown to lower endometriosis recurrence in women after conservative surgery when hormonal suppression followed, by about 59% against no treatment or placebo.

Compared with expectant management or placebo after surgery [13]

The numbers and sources

Effect: Recurrence, by imaging or return of symptoms at a median 18 months, was lower with hormonal suppression after surgery (RR 0.41, 95% CI 0.26 to 0.65, 14 studies, 1,766 patients, I² 68%). Pain scores were also lower (SMD -0.49, 95% CI -0.91 to -0.07). Results held for combined hormonal contraceptives and the levonorgestrel IUD, and in analyses limited to randomized trials [13].
Population: 2,137 premenopausal women who kept at least one ovary, in 13 randomized trials and 4 cohort studies [13].
Sources: [13]
Caveats: Heterogeneity was substantial. Suppression prevents pregnancy while it is used [13].

Endometriosis surgeryLimitedStudied in women

Hysterectomy compared with excision alone

Linked to fewer repeat operations and more pain relief than excision alone in women, in observational studies. By 7 years, 77% to 92% avoided reoperation, against 45%.

Compared with laparoscopic excision with the uterus and ovaries kept [11][12]; hysterectomy with and without removal of the ovaries, against each other [11][12]

The numbers and sources

Effect: At 2, 5 and 7 years, 79.4%, 53.3% and 44.6% of women had avoided further surgery after excision alone, against 95.7%, 86.6% and 77.0% after hysterectomy keeping the ovaries and 96.0%, 91.7% and 91.7% after hysterectomy with the ovaries removed. In women aged 30 to 39, removing the ovaries did not significantly lengthen surgery-free time [11]. At 24 months, against excision alone, hysterectomy keeping the ovaries improved pain outside periods by 1.41 more points out of 10, pain during sex by 1.12, back pain by 1.29 and quality of life by 8.77 out of 100. With the ovaries removed, the gains were 2.22, 1.05, 1.18 and 12.41 [12].
Population: 240 women at one US clinic, 120 per group [11]. Women having surgery for rectovaginal endometriosis at 86 specialist endometriosis centers, 2009 to 2021 [12].
Sources: [11], [12]
Caveats: Neither study was randomized, so women chosen for hysterectomy may differ from others. The second study's oophorectomy result was sensitive to loss to follow-up [12]. Hysterectomy ends the ability to carry a pregnancy, and removing both ovaries brings on menopause.

AcupunctureModerateStudied in women

Endometriosis pain

Mixed results: reviews of mostly unblinded trials found less endometriosis pain with acupuncture, while a sham-controlled trial found period pain eased during treatment but not 12 weeks later.

Compared with placebo, traditional Chinese medicine and Western medicine [30]; medications and herbs, and placebo in one pilot trial [31]; sham acupuncture [32]; a comparison the source abstract does not describe [33]

The numbers and sources

Effect: Across 14 studies (793 patients), pain severity fell more with acupuncture than with control treatments (SMD -1.10, 95% CI -1.45 to -0.75) [30]. Across 10 studies, pain fell 1.36 points more on a 0 to 10 scale (95% CI 1.01 to 1.72) [31]. In a sham-controlled trial of 12 weeks of treatment, period pain fell more with acupuncture by the end of treatment but not by week 24, pain lasted fewer days, and pelvic pain outside periods and pain with sex did not differ. Adverse events did not differ [32]. A Cochrane review found one trial (67 women) meeting its criteria, with lower period pain scores in the acupuncture group (MD -4.81 points) [33].
Population: 793 patients in 14 studies [30]; 10 studies of 8 to 36 patients per arm [31]; 106 women aged 20 to 40 with endometriosis pain at 4 hospitals in China [32]; 67 women [33].
Sources: [30], [31], [32], [33]
Caveats: Only one pilot trial in [31] used a placebo control, and the rest could not be blinded. The authors of [30] point to design and quality flaws in the trials.

Endometriosis surgeryLimitedStudied in womenVery common

Endometriosis coming back, and repeat surgery

Limited evidence: endometriosis returned in an estimated 21.5% of women by 2 years after surgery and 40% to 50% by 5 years.

The numbers and sources

How common: Very common: more than 1 in 10 people.
Effect: A review of published series estimated recurrence at 21.5% at 2 years and 40% to 50% at 5 years, with few consistent risk factors [14]. In one US clinic, 20.6% of women needed more surgery within 2 years of excision alone, 46.7% within 5 years and 55.4% within 7 years [11]. One year after endometrioma surgery, 32% needed more surgery after drainage and ablation and 3% to 16% after excision [10].
Population: Published surgical series [14]. 120 women after excision [11]. Women in endometrioma trials [10].
Sources: [14], [11], [10]
Caveats: The recurrence estimate comes from a narrative review, not a meta-analysis, and studies defined recurrence differently [14].

Endometriosis surgeryStrongStudied in women

Excision compared with ablation

Not shown to differ: excision and ablation eased pain from superficial endometriosis in women by similar amounts at 12 months, in two reviews.

Compared with ablation of the lesions [4][5][6][7]

The numbers and sources

Effect: Pooled across 3 trials, reductions in period pain (MD -0.03, 95% CI -1.27 to 1.22), pain with bowel movements (MD 0.46, 95% CI -1.09 to 2.02) and pain during sex (MD 0.10, 95% CI -2.36 to 2.56) did not differ at 12 months, nor did scores beyond 12 months [5]. Overall pain at 12 months did not differ in the Cochrane review (MD 0.00, 95% CI -1.22 to 1.22, 1 trial, 103 women) [4]. A blinded trial found no difference in overall pain at 12 months [6]. In a robot-assisted trial, the only difference was in pain during sex at 6 months, which favored ablation [7].
Population: 346 women with minimal to mild endometriosis in 4 trials [5]. 103 women [4]. Women with pelvic pain and visible endometriosis [6]. 73 women with minimal to mild endometriosis [7].
Sources: [5], [4], [6], [7]
Caveats: These trials covered superficial, minimal to mild disease, not deep endometriosis. The reviewers call for larger trials with longer follow-up [5].

Practices

TENSLimitedStudied in women

Endometriosis pain

Limited evidence: one trial of 101 women found pelvic pain eased only when TENS was added to hormonal treatment. A before-and-after study found no significant pain change.

Compared with hormonal treatment alone [14]; the same women before using TENS [15]

The numbers and sources

Effect: Pelvic pain fell from 7.11 to 4.55 with TENS added to hormonal treatment (p < 0.001), with relief seen only in that group. Pain during sex improved in both groups [14]. In a study with 3 months without and 3 months with TENS, pain fell 2.29 points (p = 0.44), quality of life improved 16.57 points (p < 0.001) and daily ibuprofen fell 93 mg (p = 0.02) [15].
Population: 101 women with deep endometriosis on hormonal treatment, for 8 weeks [14]. Women aged 18 to 45 with surgically confirmed endometriosis [15].
Sources: [14], [15]
Caveats: The trial abstract reports changes within each group, not a difference between them, and there was no sham [14]. The second study had no control group [15].

Heat therapyUntested

Endometriosis pain

Not studied in people. Users report: 70% of 484 Australian women with endometriosis used heat, rating it 6.5 out of 10 for pain relief.

No study in people. This rests on what users report.

The numbers and sources

Effect: In a national online survey, heat was the most common self-management strategy (70%), with a mean self-rated effectiveness for pain of 6.52 on a 10-point scale [12]. A narrative review notes that women with endometriosis frequently use heating devices for period and pelvic pain [13].
Population: 484 women aged 18 to 45 in Australia with confirmed endometriosis, recruited through support groups [12].
Sources: [12], [13]
Caveats: A self-selected survey with no comparison group. No trial of heat for endometriosis pain was located.

Daily life

Physical activityLimitedStudied in women

Endometriosis symptoms in trials

Limited evidence: a review of 6 small trials found exercise improved pain-related quality of life in women with endometriosis, from a pooled analysis of 2 trials.

Compared with activities of daily living or conventional treatment [26]

The numbers and sources

Effect: The trials reported better quality of life, pain intensity, mental health, pelvic floor function and bone density with exercise. Pooling 2 trials, the pain domain of quality of life improved (P < 0.0001), along with control and powerlessness and emotional well-being [26].
Population: 251 women with endometriosis in 6 RCTs [26].
Sources: [26]
Caveats: Outcomes differed between trials and were incompletely reported, so only 2 could be pooled. Trials were short, and the abstract gives no effect size for pain [26].

Lab markers

Anti-Müllerian hormone (AMH)ModerateStudied in women

Ovarian endometriomas

Linked to lower AMH in women with ovarian endometriomas that had not been operated on, against women without them, in a meta-analysis of 17 studies.

The numbers and sources

Effect: AMH was lower in women with unoperated endometriomas than in women without endometriomas (mean difference -0.84, 95% CI -1.16 to -0.52). It was also lower than in women with other benign ovarian cysts (-0.85, -1.37 to -0.32) and than in women with healthy ovaries (-0.61, -0.99 to -0.24) [26].
Population: 968 women with endometriomas and 1,874 without, in 17 studies [26].
Sources: [26]
Caveats: Observational. The abstract does not state the unit of the mean differences [26]. It covers endometriomas, the cysts endometriosis forms in the ovary, not endometriosis elsewhere in the pelvis. On this page, AMH tracks the number of eggs collected in IVF more closely than the chance of natural conception.

25-hydroxyvitamin DModerateStudied in women

Endometriosis

Mixed results: one meta-analysis linked endometriosis to lower vitamin D, while a second review of nine studies found three showed no difference.

The numbers and sources

Effect: In 9 studies, women with endometriosis had lower vitamin D than controls (standardized mean difference -0.97, 95% CI -1.80 to -0.14), and lower in stage III to IV than in stage I to II (-1.33, -2.54 to -0.12). Vitamin D deficiency was not significantly more common (odds ratio 2.77, 0.85 to 6.08) [26]. A second review of 9 studies found that 6 reported a difference in 25-hydroxyvitamin D between women with and without endometriosis and 3 did not [27].
Population: 9 studies [26]. 976 women with endometriosis and 674 controls in 9 studies [27].
Sources: [26], [27]
Caveats: Observational, with high heterogeneity. The gap was larger in women not using hormones, so hormone treatment may affect the comparison [26].

High-sensitivity C-reactive protein (hs-CRP)LimitedStudied in women

Endometriosis

Mixed results: six studies in a Cochrane review found no CRP difference with endometriosis, while a US survey linked endometriosis to 60% higher odds of CRP above 3 mg/L.

The numbers and sources

Effect: A Cochrane review of blood tests for endometriosis found six studies that showed no difference in CRP or hs-CRP between women with endometriosis confirmed at surgery and women without it, across stages I to IV. One used an hs-CRP assay in 834 participants and the others a standard CRP assay in 499. The reviewers concluded that CRP measured either way is not a reliable marker of endometriosis [23]. In a national US survey, women who reported a diagnosis of endometriosis had greater odds of CRP above 3.0 mg/L than women without it (adjusted odds ratio 1.60, 95% CI 1.05 to 2.45) [24].
Population: 1,333 participants in six studies, within a review whose studies enrolled women having surgery for suspected endometriosis, infertility or an ovarian mass [23]. 2,342 women in the National Health and Nutrition Examination Survey, 1999 to 2002 [24].
Sources: [23], [24]
Caveats: Observational. In the survey, endometriosis was self-reported, and the abstract does not list what the model adjusted for, so body weight may not be accounted for [24]. The Cochrane review rated all its included studies as of poor methodological quality [23].

Follicle-stimulating hormone (FSH)LimitedStudied in women

Endometriosis

One small study in a Cochrane review found no difference in FSH or LH between women with and without endometriosis.

The numbers and sources

Effect: A Cochrane review of blood tests for endometriosis found one study in which FSH and LH did not differ significantly between women with endometriosis confirmed at surgery and women without it. The reviewers describe this as consistent with other studies of hormones in endometriosis and did not recommend further study of these hormones as diagnostic markers [17].
Population: 49 participants in one study [17].
Sources: [17]
Caveats: One small study, which could miss a modest difference. The review rated all its included studies as of poor methodological quality [17].

HemoglobinLimitedStudied in women

Endometriosis

One small study in a Cochrane review found hemoglobin did not differ between women with and without endometriosis.

The numbers and sources

Effect: A Cochrane review of blood tests for endometriosis listed hemoglobin, with platelet count and other blood count measures from the same study, among markers that did not differ between women with endometriosis confirmed at surgery and women without it. The reviewers did not recommend further study of these as diagnostic markers [24].
Population: 94 participants in one study [24].
Sources: [24]
Caveats: One small study, and the review rated all its included studies as of poor methodological quality [24].

High-sensitivity C-reactive protein (hs-CRP)LimitedStudied in women

Detecting endometriosis

Limited evidence: in a Cochrane review, three studies of hs-CRP gave sensitivities of 41% to 83% and specificities of 47% to 87% against surgery.

The numbers and sources

Compared with: Endometriosis seen at surgery (laparoscopy)
Effect: Three studies with six data sets tested hs-CRP against surgical findings at cut-offs that varied, with sensitivities of 0.41 to 0.83 and specificities of 0.47 to 0.87. The highest figures, 0.83 and 0.87, came from one study of 95 women sampled in the follicular phase. Five of the data sets drew on overlapping groups of women, so the results were not pooled. The review set a sensitivity of 0.94 and a specificity of 0.79 as the accuracy a blood test would need to replace diagnostic surgery. Across 122 blood markers in 141 studies, none consistently met its criteria for replacing surgery or for triage, and the reviewers concluded that none was accurate enough for clinical use outside research [23].
Population: 506 participants in three studies of hs-CRP, within 141 studies of 15,141 women [23].
Sources: [23]
Caveats: The review rated every included study as of poor methodological quality, and the women were already having surgery, with endometriosis in 10% to 85% of them, so the figures may not hold for women tested for symptoms alone. Its searches ran to 2015 [23].

Luteinizing hormone (LH)LimitedStudied in women

Endometriosis

One small study in a Cochrane review found no difference in LH or FSH between women with and without endometriosis.

The numbers and sources

Effect: A Cochrane review of blood tests for endometriosis found one study in which LH and FSH did not differ significantly between women with endometriosis confirmed at surgery and women without it. The reviewers describe this as consistent with other studies of hormones in endometriosis and did not recommend further study of these hormones as diagnostic markers [16].
Population: 49 participants in one study [16].
Sources: [16]
Caveats: One small study, which could miss a modest difference. The review rated all its included studies as of poor methodological quality [16].

ProlactinLimitedStudied in women

Detecting endometriosis

Limited evidence: in one study within a Cochrane review, prolactin above 14.8 ng/mL detected endometriosis with 44% sensitivity and 94% specificity, which the reviewers judged too insensitive.

The numbers and sources

Compared with: Endometriosis seen at surgery
Effect: One study with two data sets tested prolactin in the luteal phase. Above 14.8 ng/mL it had a sensitivity of 0.44 (95% CI 0.32 to 0.58) and a specificity of 0.94 (0.80 to 0.99), and above 20 ng/mL 0.21 and 1.00. The reviewers judged the sensitivity unacceptably low even for a triage test. Across 122 blood markers, they found none accurate enough to replace surgery or for clinical use outside research [18].
Population: 97 participants in one study [18].
Sources: [18]
Caveats: One study, and the review rated all its included studies as of poor methodological quality [18]. Stress at the blood draw also raises prolactin (see Stress at the blood draw and timing).

On a blood test: High-sensitivity C-reactive protein (hs-CRP)

Every finding in the library that measured this test, including studies that were mainly about something else (leaving out those done only in men or only in children).

Shown to lower it

Strong
Thunder god vineCautionRheumatoid arthritis
Across 40 RCTs (3,092 patients), tripterygium glycosides added to DMARDs lowered morning stiffness, tender and swollen joint counts, pain scores, CRP, ESR and rheumatoid factor against DMARDs alone (all p < .001).
Strong
TurmericC-reactive protein and other inflammation markers
Shown to lower CRP and some other inflammation markers in adults with inflammatory conditions or diabetes. These are blood markers, not clinical outcomes.
Strong
TurmericRheumatoid arthritis
Across 7 RCTs, DAS28 fell by 1.47 (95% CI -1.68 to -1.26), with lower rheumatoid factor, ESR and CRP.
Moderate
Oral corticosteroidsSevere COVID-19 and pneumonia in hospital
In severe community-acquired pneumonia, added corticosteroids lowered deaths (RR 0.47, 95% CI 0.3 to 0.74) and C-reactive protein on day 8 (SMD -0.8, 95% CI -1.11 to -0.5), with no difference in gastrointestinal bleeding or high blood sugar.
Moderate
Beta-sitosterolBlood pressure and other heart risk markers
Plant sterols and stanols lowered systolic blood pressure by 1.55 mmHg (95% CI 0.42 to 2.67), diastolic by 0.84 mmHg, apoB by 0.06 g/L and hs-CRP by 0.25 mg/L.
Moderate
Fisetin and quercetin (senolytics)Liver enzymes and lipids in fatty liver disease (quercetin alone)
A 2025 meta-analysis of 7 RCTs (540 patients) with metabolic dysfunction-associated steatotic liver disease found that quercetin lowered ALT, AST, GGT, direct bilirubin and C-reactive protein, lowered total cholesterol, LDL and triglycerides, and raised HDL.
Moderate
GarlicInflammation markers
Shown to lower CRP by about 0.6 mg/L and lower TNF in adults. These are blood markers, and the reviews disagree on IL-6.
Moderate
GingerInflammation markers
Shown to lower CRP, TNF-α and IL-6 in adults, more in people with health conditions. These are blood markers, not clinical outcomes.
Moderate
ProbioticsRheumatoid arthritis
Mixed results: reviews agree probiotics lower CRP or IL-6 in rheumatoid arthritis, but disagree on disease activity.
Moderate
Tart cherryRecovery after strenuous exercise
A 2026 meta-analysis of 19 trials in trained athletes found faster recovery of maximal strength at every time point (ES 0.63 right after exercise to 4.82 at 96 hours) and lower CRP up to 48 hours (ES -0.46 to -0.73).
Moderate
Vitamin DInflammatory bowel disease
In adults, the Harvey Bradshaw Index for Crohn's disease fell by 1.47 points (95% CI -2.47 to -0.47) and hs-CRP fell by 1.58 mg/L.
Moderate
ZincBlood sugar
Across 32 placebo-controlled interventions (1,700 participants, 14 countries), zinc lowered fasting glucose by 14.15 mg/dL (95% CI -17.36 to -10.93), 2-hour glucose by 36.85 mg/dL, HbA1c by 0.55% (95% CI -0.84 to -0.27) and hs-CRP by 1.31 mg/L.
Moderate
Red light therapyWeight and waist size in obesity
Across 11 RCTs (569 patients), photobiomodulation improved waistline (mean difference -7.28, 95% CI -9.97 to -5.67), weight (-3.54, 95% CI -5.97 to -1.11) and BMI (-1.18, 95% CI -1.93 to -0.43), and lowered C-reactive protein, total cholesterol and HOMA-IR.
Moderate
Paleo dietInflammation markers
Shown in two reviews to lower CRP about 0.4 to 0.8 mg/L more than comparison diets in adults, with one result sensitive to single trials.
Compared with control diets the source does not describe; a control group the source does not describe
Limited
BoronJoint pain and arthritis
In 60 adults with knee osteoarthritis, 15 days of calcium fructoborate improved C-reactive protein, fibrinogen and sedimentation rate against placebo, with no serious adverse events.
Limited
Grape seed extractInflammation
Limited evidence: a 50-trial review found lower CRP, while an earlier review found no effect.
Limited
Tart cherryKnee osteoarthritis pain
One trial found knee pain scores did not differ significantly from placebo in adults with knee osteoarthritis, though CRP fell.
Limited
Urolithin AMitochondrial and cellular markers
Acylcarnitines, ceramides and CRP fell more than on placebo in older adults over 4 months, and acylcarnitines and CRP fell in middle-aged adults.
Limited
Lymphatic drainage massageMuscle recovery after hard exercise
One trial of 36 combat athletes found drainage after jumping exercise raised pain thresholds and lowered creatine kinase and C-reactive protein more than passive rest.
Compared with passive rest; intense sports massage
Limited
Juice cleanseStudied in womenInflammation
One trial found the inflammation marker hs-CRP fell on a 7-day lemon detox but not on a calorie-matched placebo juice, in overweight Korean women.
Compared with before the diet, in the same people (overweight Korean women), with a calorie-matched placebo juice group measured the same way

Shown to raise it

Moderate
CLAInflammation and oxidative stress markers
Shown to raise CRP in adults across 14 studies. Sources disagree on oxidative stress, with one marker rising and another falling.

Studies disagree

Strong
Dietary nitrateRecovery from muscle damage
Creatine kinase and oxidative stress did not change; C-reactive protein was higher than placebo at 48 hours (SMD 0.55). CRP, IL-6 and TNF-α did not change.
Strong
Tart cherryBlood pressure and cardiometabolic markers
Across 21 trials, blood pressure, heart rate, hs-CRP and IL-6 did not change, while CRP fell by 0.39 mg/L (95% CI -0.74 to -0.05, moderate certainty).
Strong
Vitamin DRheumatoid arthritis disease activity
Shown to lower disease activity modestly in adults with rheumatoid arthritis. Reviews disagree on CRP, ESR and pain.
Moderate
ResveratrolInflammation and blood lipids
Mixed results: reviews disagree on whether CRP falls, and most found no change in LDL or triglycerides.
Moderate
Fermented foodsInflammation and C-reactive protein
Mixed results: one meta-analysis found fermented dairy lowered C-reactive protein slightly, while two meta-analyses of kefir trials found no change.
Compared with control groups the abstract does not describe; people who did not drink kefir; control groups; a high-fiber diet, with changes measured over time in each group
Moderate
Olive oilInflammation
Mixed results: one pooled analysis found C-reactive protein fell 0.64 mg/L with olive oil, while a later one found no change in C-reactive protein or interleukin-6.
Compared with control groups, with control diets that varied; trials comparing olive oil or flaxseed oil with controls
Moderate
Whole grainsC-reactive protein and inflammation
Mixed results: two pooled analyses of trials found whole grains lowered C-reactive protein slightly, while a third found no significant change.
Compared with refined grains; refined grains or placebo; control diets low in or without whole grains
Moderate
Keto dietInflammation markers
Mixed results: CRP fell 0.62 mg/dL in one review of short and long trials, and a review of trials lasting a year or more found no CRP difference.
Compared with diets that did not restrict carbohydrates to the level of ketosis
Limited
Fish oilInflammation markers (CRP)
Limited evidence: CRP fell in hemodialysis patients but not with high-dose EPA, in knee osteoarthritis, or in most trials of trained people.
Limited
PalmitoylethanolamideInflammation markers (CRP, IL-6)
Small trials found lower IL-6 and CRP in diabetic nerve pain, while a COVID-19 trial lowered other markers but not those two.
Limited
MeditationInflammation and C-reactive protein
Mixed results: one meta-analysis found C-reactive protein fell against active controls, while a review of trials found a fall in three of six that measured it.
Compared with active control groups; waiting list, usual care and active control groups

Tested, and not shown to change it

Strong
TMGHigher cholesterol
Triglycerides, HDL, glucose, CRP, liver enzymes and blood pressure did not change.
Strong
Vitamin DPsoriasis severity
Across 4 studies (333 patients), PASI, DLQI and CRP changes did not differ from control.
Strong
NutsInflammation and blood vessel function
Not shown to lower C-reactive protein in two meta-analyses of nut trials. Blood vessel widening, a measure of vessel function, improved in one.
Compared with control conditions the abstract does not describe; control arms without nuts
Moderate
AstaxanthinOxidative stress and inflammation
Shown to lower blood malondialdehyde, an oxidative stress marker, and IL-6 in type 2 diabetes. CRP and TNF-alpha did not change.
Moderate
Fish oilCardiovascular outcomes with purified EPA (prescription)
Across 6 trials (42,738 adults) of 1.8 g a day or more of EPA-dominant omega-3, hospitalization for unstable angina fell (RR 0.75, 95% CI 0.66 to 0.87), while cardiovascular death, ischemic stroke and hs-CRP did not change significantly.
Moderate
Fish oilRheumatoid arthritis
Across 18 RCTs (1,018 patients), tender joint count fell (SMD -0.59, 95% CI -0.79 to -0.39), while ESR, CRP and DAS28 did not change significantly.
Moderate
LactoferrinRespiratory infections
In adults, IL-6 fell by 24.9 pg/mL, while CRP and NK cell activity did not change.
Moderate
RhodiolaEndurance performance
Creatine kinase (ES -0.84) and lactate fell, and IL-6 and CRP did not change.
Moderate
Cold water immersionInflammation
Not shown to lower inflammation. Inflammatory markers rose in the hour after immersion, and post-exercise reviews found no change in C-reactive protein or interleukin-6.
Moderate
Whole-body cryotherapyAnkylosing spondylitis
Shown to improve pain, function and disease activity scores in people with ankylosing spondylitis in a meta-analysis of 5 studies. C-reactive protein did not change.
Moderate
High-protein dietBlood pressure and triglycerides
Total and LDL cholesterol, C-reactive protein and HbA1c did not change.
Compared with diets with less protein
Moderate
Nordic dietInflammation markers
Not shown to change CRP, IL-6 or TNF-alpha in adults in Nordic countries.
Compared with control groups the source does not describe
Limited
Deer antler velvetArthritis
In 168 people with rheumatoid arthritis on standard treatment, 6 months of elk velvet antler did not differ from placebo on joint pain and swelling, disease activity, function, quality of life or CRP.
Limited
Green-lipped musselInflammation markers (CRP)
Small trials found no change in CRP in knee osteoarthritis, and lower airway inflammation markers in asthma.
Limited
L-carnitineTMAO and cardiovascular markers
In healthy older women, 24 weeks of L-carnitine raised plasma TMAO tenfold but did not change CRP, IL-6, adhesion molecules or lipids.
Limited
CuppingInflammation, wet cupping
One trial of 126 people with metabolic syndrome found wet cupping did not change high-sensitivity C-reactive protein over 12 weeks.
Compared with dietary advice alone

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