Effect of Curcumin Nanomicelle on the Intensity of Dysmenorrhea in Endometriosis Patients: A Randomized Triple-Blind Placebo-Controlled Trial

Endometrial tissue outside the uterus is a defining feature of endometriosis, a persistent gynecological condition. It is associated with infertility and pelvic discomfort (1). Ectopic endometrial tissue is usually located in the pelvis but can manifest in many other areas of the body. The most common areas of involvement include the ovaries, uterosacral and broad ligaments, fallopian tubes, appendix, and the sigmoid colon (2). Based on epidemiological data, the incidence of endometriosis in a typical population is estimated to be 4-15%, which varies depending on the source of the disease (3). The primary suspicion of its existence is based on clinical symptoms. The symptoms of endometriosis include infertility, dyspareunia, dyschezia, pelvic pain, and dysmenorrhea (4). The gold standard diagnostic method is the observation of endometriotic lesions upon surgery with or without biopsy (5). Endometriosis is the most common cause of secondary Effect of Curcumin Nanomicelle on the Intensity of Dysmenorrhea in Endometriosis Patients: A Randomized Triple-Blind Placebo-Controlled Trial Malihe Amirian1 ID , Navid Omidkhoda2 ID , Leli Hafizi3 ID , Maliheh Mahmoudinia4 ID , Shabnam Niroumand5 ID , Amir Hooshang Mohammadpour2,6 ID , Shima Hatami7* ID 1Department of Reproductive Medicine and Gynecology, Milad (Mashhad) Infertility Center, Mashhad University of Medical Sciences, Mashhad, Iran 2Department of Clinical Pharmacy, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran 3Department of Obstetrics and Gynecology, Women’s Health Research Center, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 4Department of Obstetrics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 5Department of Community Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran 6Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran 7Department of Obstetrics and Gynecology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran *Corresponding Author: Shima Hatami, Email: [email protected] https://jkmu.kmu.ac.ir 10.34172/jkmu.3820 JKMU. 2025;32:3820 Original Article © 2025 The Author(s); Published by Kerman University of Medical Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Background: Consisting of endometrial tissue outside the uterus, endometriosis is a persistent gynecological illness that causes infertility, pelvic pain, and dysmenorrhea. Curcumin is a bioactive ingredient derived from the spice turmeric and has many pharmacological properties. This study aimed to determine how curcumin affected the severity of dysmenorrhea in patients with endometriosis.

This research was a triple-blind, randomized-controlled clinical trial conducted on patients referred to the gynecological clinic at the Ghaem and Imam Reza hospitals in Mashhad, Iran. Participants were randomly allocated to the placebo (n = 25) and curcumin nanomicelle (n = 25) groups. Each patient received two capsules daily (intervention: 40 mg of curcumin nanomicelle; control: placebo) for three months. Before treatment and at the end of the first, second, and third months, the severity of dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain was measured using the visual analog scale (VAS). The data were analyzed using SPSS version 26.

The initial and final dysmenorrhea intensity scores differed by 1.66 ± 2.05 and 4.56 ± 1.66 in the placebo and curcumin groups, respectively (P < 0.001). The placebo and curcumin groups had significantly higher rates of dyspareunia (P < 0.02), dyschezia (P < 0.02), and chronic pelvic pain (P < 0.001).

Although we have limitations, such as the small sample size and restricted generalizability of the results to other populations, our findings demonstrate the possible benefits of curcumin in the improvement of dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain in patients with endometriosis.

Endometriosis, Dysmenorrhea, Complementary therapy, Herbal medicine, Pelvic pain Received: November 17, 2023, Accepted: April 9, 2025, ePublished: October 11, 2025 Citation: Amirian M, Omidkhoda N, Hafizi L, Mahmoudinia M, Niroumand S, Mohammadpour AH, et al. Effect of curcumin nanomicelle on the intensity of dysmenorrhea in endometriosis patients: a randomized triple-blind placebo-controlled trial. Journal of Kerman University of Medical Sciences. 2025;32:3820. doi:10.34172/jkmu.3820 Journal of Kerman University of Medical Sciences Open Access Publish Free Amirian et al Journal of Kerman University of Medical Sciences. 2025;32:38202 dysmenorrhea (6). Endometriosis’ dysmenorrhea usually begins before menstruation and persists during or after this period. This pain is regularly diffused through the pelvis or spread over the back, and may be accompanied by pressure in the rectum, nausea, and transient diarrhea (7). It is hypothesized that the mechanism of dysmenorrhea in endometriosis patients is related to prostaglandins (PGs) because of their higher concentration in the menstrual blood of these patients (8). A study by Bulletti et al revealed that uterine contractions had higher frequency, amplitude, and basal pressure tone in women with endometriosis (9). Hence, severe dysmenorrhea in women with endometriosis may be a consequence of abnormal contractions of the uterus. Although many chemical drugs are used to reduce the intensity of endometriosis’ dysmenorrhea, their consumption has been limited due to a wide range of adverse effects (10). Hormonal therapy, including combined estrogen-progestin contraceptives, progestogens, and gonadotropin-releasing hormone (GnRH) analogues, seeks to restrict ovarian hormone production to minimize endometriotic lesion activity. However, these treatments typically provide temporary relief, with symptoms recurring after therapy is ceased. Furthermore, not all patients have adequate pain relief throughout treatment (11). Long-term use of hormonal treatments can lead to side effects such as bone density loss, mood changes, weight gain, and vasomotor symptoms. For instance, GnRH analogs induce a hypoestrogenic state, potentially causing menopausal-like symptoms and decreasing bone mineral density (12). Given these limitations, there is a compelling need to explore alternative treatments that offer effective symptom relief with fewer side effects. Alternatively, herbal medicine and complementary products such as ginkgo, magnesium pyrrolidone, saffron, St. John’s Wort, soy, and vitamin E are being administered extensively in many inflammatory conditions, such as premenstrual syndrome (PMS) and dysmenorrhea (13). Turmeric is the source of curcumin, a bioactive substance that belongs to the Zingiberaceae family. Curcumin has many pharmacological properties, including anti-inflammatory, antineoplastic, antioxidant, cardioprotective, immunomodulatory, lipid-lowering, antidepressant, and analgesic (14-16). Curcumin’s therapeutic use has been affected by its low bioavailability due to low solubility and rapid metabolism. Curcumin’s bioavailability and therapeutic efficacy have been improved using nanotechnology-based delivery technologies, such as nanomicelle. Nano-micelles can enhance curcumin’s solubility, stability, and absorption, potentially improving its therapeutic efficacy in endometriosis patients (17). It is interesting to note that curcumin has been demonstrated to suppress PG formation by inhibiting the cyclooxygenase-2 (COX-2) enzyme (18). Additionally, the clinical effects of curcumin on endometriosis have not been previously investigated. This study was thus carried out to examine the impact of curcumin nanomicelle on the severity of dysmenorrhea and other symptoms, including dyspareunia, dyschezia, and chronic pelvic pain in patients with endometriosis, based on the role of PGs in endometriosis’ dysmenorrhea.

Study Design This study was a triple-blind, randomized clinical trial with control and intervention groups, performed from December 2020 to November 2021, at the gynecology clinic of Ghaem and Imam Reza hospitals affiliated with the Mashhad University of Medical Sciences, Mashhad, Iran. To report this clinical research, we followed the CONSORT reporting criteria (19). Study Population Sixty patients with endometriosis were assessed, and 50 patients were included in the study based on inclusion and exclusion criteria. The following were the requirements for inclusion: diagnosis of endometriosis based on ultrasound, magnetic resonance imaging (MRI), or surgery (based on persistent cyst or typical endometriosis profile); complaints of dysmenorrhea; and age of 15-45 years. The exclusion criteria were treatment with GnRH agonist or antagonist drugs, other medical treatments such as dinogest and contraceptives, the intention to become pregnant, and any major allergic reaction related to curcumin. Study Protocol Patients who qualified were divided into two groups randomly: the curcumin nanomicelle group and the placebo group. The intervention group received two oral capsules (red oval soft gel capsules) of curcumin nanomicelle (40 mg) (Cinacurcumin, Minoo Pharmaceutical Company, Tehran, Iran) daily for three months. The encapsulation percentage of curcumin in the formulation was approximately 100%. In addition, it has been demonstrated that the bioavailability of curcumin nanomicelle is significantly higher than that of other formulations (20). The control group was concurrently treated with two placebo capsules (red oval soft gel capsules) per day. Patients in both groups only received non-steroidal anti-inflammatory drugs (NSAIDs) as a standard treatment in cases of extreme pain because they had low stages of endometriosis. We measured characteristics such as age (year), BMI, marital status, parity status, dysmenorrhea, dyspareunia, dyschezia, and pain severity between periods at baseline. The severity of dysmenorrhea, dyspareunia, dyschezia, and pain severity between periods was measured by the visual analog scale (V AS) score. A gynecologist used the V AS score to assess the severity of dysmenorrhea, dyspareunia, dyschezia, and pain severity between periods on the first day of Journal of Kerman University of Medical Sciences. 2025;32:3820 3 Curcumin and intensity of dysmenorrhea in endometriosis patients menstruation before beginning treatment. The V AS uses a 10-cm horizontal line with a score range of 0–10. Zero traditionally denotes “no pain at all, ” while 10 implies the “worst pain” that is physically possible. The treatment began on that day (the first day of menstruation). The gynecologist was trained to use the V AS scale consistently by participating in educational workshops and simulation- based trainings. We conducted workshops that provided comprehensive education on the V AS, including its purpose, application, and interpretation. Furthermore, simulation-based training provided an excellent opportunity for the gynecologist to improve her skills in administering the V AS. By participating in realistic scenarios with standardized patients, the practitioner developed her communication skills, gained confidence, and ensured adherence to standardized procedures, resulting in better patient outcomes. During the three months of treatment, patients were evaluated according to the intensity of dysmenorrhea, dyspareunia, dyschezia, and pain severity between periods at 4-time points, before the treatment, at the end of the first month, at the end of the second month, and finally, at the end of the third month (the last appointment and the end of the treatment). However, detecting the differences within each study group over time was also important and was assessed. To detect any overall differences within each group, we calculated the difference between initial and final measurements. Outcome The severity of dysmenorrhea was assessed and compared with the placebo group as a primary endpoint, and the severity of dyspareunia, dyschezia, and chronic pelvic pain was measured and compared with the placebo group as our secondary endpoints. Additionally, medication adherence was assessed at each visit. Randomization and Blinding The random allocation sequence was created using a computer-generated randomized list that was obtained from the randomization.com website. The Minoo Company packed bottles with a placebo and nanocurcumin, then numbered them (a number between 1 and 50) according to the allocation order. The clinical pharmacist or physician, depending on which patient met the inclusion criteria, gave the boxes to them. The physician assessed the patients while they were receiving treatment. The clinical pharmacist handled the data entry and gathering into the SPSS program. The patients’ group assignment was undisclosed to the clinicians. Before the clinical pharmacist analysis of the data, grouping data were added to the SPSS file according to the allocation sequence, but only as group 1 or 2, by a third party who was not involved in the investigation. As a result, the clinical pharmacist was unaware of the patient’s allocation to treatments or placebos. Following the analysis, the third party defined codes 1 and 2. Thus, the patient’s group assignment was unknown to the physician, the clinical pharmacist, or the surgery specialist. Sample Size Calculation and Statistical Analysis Since this study was intended to be a pilot study, the sample size was determined using the formula below. Based on the findings of the Warzecha et al study (5), the sample size was determined to be 22 by assuming equal variances and taking into account a two-level reduction in dysmenorrhea pain that was substantial in the view of our experts. Statistical analysis was performed using SPSS version 26. Descriptive statistics (mean and standard deviation) were calculated for age, body mass index (BMI), marital status, and parity. Categorical variables were compared with the chi-square test. The Kolmogorov- Smirnov test was used to assess the normality of the data. To compare the mean or median between two independent groups, the independent t-test and the Mann-Whitney U-test were utilized, respectively. Any discrepancies between related means or medians were found using the Friedman test or repeated measures ANOV A. Statistical significance was set at P ≤ 0.05, which was considered statistically significant. ( ) ( ) 2 22 12 1 1 2 12 2 12 nn SS Z Z XX αβ −− ++  = = −

Population Study The present study was conducted on 50 patients; 25 were treated with curcumin in the intervention group, and 25 were treated with a placebo. All of these patients fulfilled the trial criteria, were enrolled in the study by protocol, and completed the whole three months of trial duration (Figure 1). We measured characteristics such as age, BMI, marital status, parity status, dysmenorrhea, dyspareunia, dyschezia, and pain severity between periods at baseline (Table 1). At baseline, there were no notable variations among the patients. Comparison of Dysmenorrhea Severity Between Placebo and Curcumin Nanomicelle Before intervention, we found no discernible difference in the severity of dysmenorrhea between the groups receiving curcumin nanomicelle and a placebo. However, pain levels in the intervention group, as mentioned in Table 2, decreased over time. In the placebo group, the pain severity decreased during the study, but not as much as in the patients treated with curcumin nanomicelle. Nevertheless, the reduction was statistically significant in the placebo group too. In addition, differences between Amirian et al Journal of Kerman University of Medical Sciences. 2025;32:38204 the initial and final scores were measured. Interestingly, we found that curcumin nanomicelle had a significantly greater effect on reducing the severity of dysmenorrhea than the placebo group (P < 0.001) (Table 3, Figure 2). Comparison of Dyspareunia Severity Between Placebo and Curcumin Nanomicelle In examining patients at baseline regarding pain during intercourse or dyspareunia, we found no substantial difference between patients in the intervention and placebo groups. After the administration of curcumin, the patient’s pain level in the intervention group decreased gradually. Curcumin significantly decreased dyspareunia at the end of the study compared to the initial examination. Also, in the placebo group, we observed a reduction in pain levels during the study ( Table 2). Ultimately, we demonstrated that dyspareunia reduction was substantially superior in the curcumin group than in the placebo group ( P < 0.02) (Table 3, Figure 3). Figure 1. Flow diagram of the trial Table 1. The Baseline characteristics of the participants Characteristics Group P valuea Placebo (n = 25) Mean ± SD Curcumin (n = 25) Mean ± SD Age (year) 31.88 ± 6.13 32.36 ± 6.21 1 BMI (kg/m2) 25.36 ± 3.23 24.76 ± 3.58 0.57 Marital status 0.74Married 18 (72%) 19 (76%) Single 7 (28%) 6 (24%) Parity status 0.56No child 15 (60%) 13 (52%) With children (1-4) 10 (40%) 12 (48%) Dysmenorrhea score 7 ± 1.44 6.88 ± 1.48 0.81 Dyspareunia score 5.9 ± 2.62 6.08 ± 1.84 0.36 Dyschezia score 5 ± 3.16 6.08 ± 1.65 0.41 Chronic pelvic pain score 5.11 ± 144 5.38 ± 1.62 0.70 a Calculated by the Mann-Whitney U test; * Significant differences vs. placebo group (*P < 0.05). Figure 2. Dysmenorrhea severity in placebo and curcumin nanomicelle groups 6.88 7 5.44 5.88 4.08 5.08 2.32 5 0 1 2 3 4 5 6 7 8 Curcumin Placebo VAS score Dysmenorrhea Baseline First Month Second Month Third Month Journal of Kerman University of Medical Sciences. 2025;32:3820 5 Curcumin and intensity of dysmenorrhea in endometriosis patients Comparison of Dyschezia Severity Between Placebo and Curcumin Nanomicelle Dyschezia or pain and difficulty during defecation severity were not statistically different at baseline between the intervention and control groups . Interestingly, pain reduction during the study period was statistically significant in the curcumin group ( P < 0.001). However, patients in the placebo group experienced less and non-significant pain reduction during the study period (P < 0.43) ( Table 2 ). Furthermore, we compared the amount of pain reduction between the placebo and the intervention groups. Finally, it was demonstrated that curcumin significantly decreased dyschezia compared to the placebo group (P < 0.02) (Table 3, Figure 4). Comparison of Chronic Pelvic Pain Between Placebo and Curcumin Nanomicelle The chronic pelvic pain in the curcumin group and the placebo group at baseline was not considerably different. Nevertheless, after curcumin treatment, the pain was reduced in the intervention group and significantly improved compared to the initial measurements. Conversely, in the placebo group, we observed a non- significant increase in pain levels during the study (Table 2). In addition, the difference in initial and final scores was measured, and the intervention group showed a significantly greater reduction in chronic pelvic pain than the placebo group (P < 0.001) (Table 3, Figure 5).

This study presents valuable results regarding the effects of curcumin nanomicelle on the intensity of dysmenorrhea pain in patients with endometriosis. Based on our findings, patients with endometriosis and dysmenorrhea after three months of treatment with curcumin nanomicelle showed significant reductions in the mean scores of dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain in comparison with the control group. To the best of our knowledge, this is the first study to investigate the effect of curcumin on dysmenorrhea intensity in patients with endometriosis. Regarding the pathophysiology of endometriosis, some ideas have been put out; the most commonly recognized of them is Sampson’s implantation theory. According to this opinion, retrograde menstruation is the mechanism by which some endometrial cells enter the peritoneal cavity (21). Therefore, the adhesion and multiplication of endometrial cells, cellular invasion, and angiogenesis are crucial in the development of endometriosis (22). The pathophysiology of endometriosis involves several inflammatory and growth factors, angiogenic stimulants, and adhesion molecules, including vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), interleukin-6 (IL-6), IL-8, and tumor necrosis factor-α (TNF-α) (21). Curcumin is an anti-inflammatory agent that has recently demonstrated additional properties such as anti-angiogenic, anti-metastatic, anti-mutagenic, and hormonal regulatory (23,24). A study performed by Zhang et al analyzed the impact of curcumin on endometrial cells in patients with endometriosis. In this Table 2. Dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain severity in placebo and curcumin nanomicelle groups Dysmenorrhea Dyspareunia Dyschezia Chronic pelvic pain Placebo (n = 25) (Median ± IQR) Curcumin (n = 25) (Median ± IQR) Placebo (n = 18) (Median ± IQR) Curcumin (n = 19) (Median ± IQR) Placebo (n = 25) (Median ± IQR) Curcumin (n = 25) (Median ± IQR) Placebo (n = 25) (Median ± IQR) Curcumin (n = 25) (Median ± IQR) First month 5.88 ± 1.71 5.44 ± 1.47 4.36 ± 2.20 4.31 ± 1.79 4.38 ± 3.62 4.15 ± 1.86 3.89 ± 1.62 3.67 ± 1.88 Second month 5.08 ± 1.86 4.08 ± 1.60 3.18 ± 1.25 2.62 ± 2.10 3.88 ± 1.80 1.92 ± 1.93 4 ± 1.76 1.57 ± 1.53 Third month 5.38 ± 1.86 2.32 ± 1.40 2.73 ± 1.42 1.38 ± 1.80 3.25 ± 1.48 1.31 ± 1.70 4.11 ± 2.49 1.10 ± 1.44 P valuea < 0.001* < 0.001* < 0.01* < 0.001* < 0.43 < 0.001* < 0.01* < 0.001* a Calculated by the Friedman test; * Significant differences vs. placebo group (*P < 0.05). Table 3. Comparison of initial and final difference scores between the placebo and curcumin groups Initial and final difference score Placebo (Median ± IQR) Curcumin (Median ± IQR) P valuea Dysmenorrhea 1.66 ± 2.05 4.56 ± 1.66 < 0.001* Dyspareunia 2.36 ± 2.78 4.69 ± 1.54 < 0.02* Dyschezia 1.75 ± 2.43 4.76 ± 2.31 < 0.02* Chronic pelvic pain 1 ± 1.88 4.28 ± 1.79 < 0.001* a Calculated by the Mann-Whitney U test; * Significant differences vs. placebo group (P < 0.05). Figure 3. Dysmenorrhea severity in placebo and curcumin nanomicelle groups 6.08 5.9 4.31 4.36 2.62 3.18 1.38 2.3 0 1 2 3 4 5 6 7 Curcumin Placebo VAS score Dyspareunia Baseline First month Second month Third month Amirian et al Journal of Kerman University of Medical Sciences. 2025;32:38206 study, endometriotic epithelial cells, normal endometrial stromal cells, normal epithelial cells, and endometriotic stromal cells were isolated from premenopausal women who had undergone hysterectomy and were fixed in 10% formalin. Then, the cells were examined for pathology and were excluded from the study in case of malignancy. Cells estradiol value and the effect of curcumin on cell proliferation were assessed. Finally, they found that curcumin inhibited cell proliferation by reducing the amount of estradiol in endometrial cells (25). Another study investigated the effect of curcumin on apoptosis and the progression of endometriosis in BALB/c mice. They carried out a three-day pretreatment of curcumin before the induction of peritoneal endometriosis, and then, a five-day treatment with curcumin or celecoxib. They reported that the development of peritoneal endometrial glands significantly decreased in the curcumin group. They also reported an increase in the ratio of B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax), elevation of mitochondrial apoptotic factors such as caspase-9 and cytochrome-c, and upregulation of anti-tumor factors like P53 in the curcumin group compared with controls (26). Furthermore, many other studies have reported similar results in terms of the effects of curcumin on the proliferation and apoptosis of endometrial cells (27-29). Angiogenesis and a new blood supply are important factors in the development of endometriosis. Interestingly, it has been reported that the angiogenic activity and concentration of angiogenic factors such as VEGF are substantially higher in women with endometriosis (30,31). Some studies have explored the antiangiogenic effects of curcumin in rodent models of endometriosis. It has been stated that curcumin can repress the micro-vessel density (MVD) in the ectopic endometrium and reduce VEGF in the serum and ectopic endometrium, while it had no substantial impact on MVD in the utopic endometrium in another investigation (32- 34). Inflammatory agents, such as TNF-α, IL-1, IL-6, IL-8, and TGF-β, play a crucial role in the pathogenesis and progression of endometriosis (35). Curcumin has been identified as a novel anti-inflammatory agent, and its effects have been proven in many studies (36,37). In a previous study, curcumin significantly decreased the secretion of IL-6, IL-8, Monocyte chemoattractant protein-1 (MCP-1), and nuclear factor kappa-light-chain- enhancer of activated B cells ( NF-κB) in human ectopic endometriotic stromal cells (38). Curcumin mainly reduces inflammation by blocking the NF-κB signaling pathway, which is a major inflammatory regulator. TNF-α and IL-6 are two pro-inflammatory cytokines that are transcriptionally triggered by NF-κB activation. By blocking the phosphorylation and degradation of IκBα, curcumin inhibits NF-κB activation and prevents NF-κB from translocating to the nucleus. This results in reduced expression of TNF-α, IL-6, and other inflammatory mediators (38- 40). In another study conducted by Soetikno et al in rats, curcumin treatment significantly reduced the abundance of COX-2, NF-κB, TNF-α, and malondialdehyde (MDA) levels (41). A randomized, double-blinded clinical trial consisting of 70 patients demonstrated that curcumin has a substantial effect on PMS symptoms, probably due to its anti-inflammatory effects (42). In another randomized controlled study of 76 female patients treated with curcumin for three months, curcumin had a brilliant effect on PMS symptoms and dysmenorrhea in comparison with the control group (43). In addition, a triple-blind, placebo-controlled clinical trial investigated the effects of curcumin on menstrual patterns, PMS, and dysmenorrhea. They enrolled 124 patients and divided them into two groups. They treated patients in the intervention group with curcumin for three months. Eventually, they reported a significant improvement resulting from curcumin in PMS symptoms and dysmenorrhea (44). Furthermore, another clinical trial reported that the co-administration of curcumin and mefenamic acid could have a significant effect on primary dysmenorrhea (45). Specifically, many studies Figure 4. Dyschezia severity in placebo and curcumin nanomicelle groups Figure 5. Chronic pelvic pain severity in placebo and curcumin nanomicelle groups 6.08 5 4.15 4.38 1.92 3.88 1.31 3.25 0 1 2 3 4 5 6 7 Curcumin Placebo VAS score Dyschezia Baseline First month Second month Third month 5.38 5.11 3.67 3.89 1.57 4 1.1 4.11 0 1 2 3 4 5 6 Curcumin Placebo VAS score Chronic pelvic pain Baseline First month Second month Third month Journal of Kerman University of Medical Sciences. 2025;32:3820 7 Curcumin and intensity of dysmenorrhea in endometriosis patients have reported that curcumin represses the synthesis of PGs through inhibition of the COX-2 enzyme (18). Furthermore, it has been mentioned that the main mechanism of dysmenorrhea in endometriosis patients is related to PGs because of their higher concentration in the menstrual blood of these patients (46). In this study, we investigated the effect of curcumin on the intensity of dysmenorrhea in endometriosis patients, which showed significant reductions in the mean scores of dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain compared to those in the control group. Nonetheless, we had some limitations, such as a small sample size due to the limited number of patients who fulfilled the inclusion criteria and the shortness of the follow-up period. A longer follow-up period and combining curcumin with other treatments would reveal more accurate results about the efficacy and adverse effects of curcumin nanomicelle on patients. Apart from that, demographic factors such as age, marital status, parity, and education level can significantly impact the prevalence and severity of dysmenorrhea and other endometriosis-related symptoms. These demographic variables can influence both the perception and reporting of symptoms, potentially affecting the outcomes of interventions like curcumin nanomicelle (47). Although there were no significant differences between the placebo and intervention groups in terms of age, marital status, parity, and BMI at baseline, we did not record education level. Future research should include education level as a compounding component. Finally, our study’s limitations include the limited generalizability of our findings to other populations due to the small sample size and rigid inclusion criteria. Our study had several strengths, including a randomized, triple-blind, and placebo- controlled design and three months of treatment with curcumin nanomicelle as an identified and standard active turmeric plant constituent.

The results of this randomized, triple-blind, placebo- controlled clinical trial indicated that patients with endometriosis who used two oral capsules (40 mg) of curcumin nanomicelle daily for three months reported a significant reduction in the severity of dysmenorrhea, dyspareunia, dyschezia, and chronic pelvic pain based on the V AS score. Although the severity reduction was significant in the placebo groups, the reduction was significantly greater in the curcumin groups than in the placebo groups. To assess the impact of curcumin on patients with endometriosis more accurately, more clinical trials with larger sample sizes and longer follow- ups are necessary. Acknowledgments The authors appreciate Mashhad University of Medical Sciences for funding this study. Authors’ Contribution Conceptualization: Shima Hatami, Malihe Amirian. Data curation: Shima Hatami. Formal analysis: Shima Hatami, Malihe Amirian. Funding acquisition: Malihe Amirian. Investigation: Malihe Amirian. Methodology: Leli Hafizi. Project administration: Shima Hatami, Navid Omidkhoda. Resources: Malihe Amirian. Software: Shabnam Niroumand. Supervision: Malihe Mahmoudinia, Amir Hooshang Mohammadpour. Validation: Malihe Mahmoudinia, Amir Hooshang Mohammadpour, Maliheh Amirian. Visualization: Navid Omidkhoda, Amir Hooshang Mohammadpour. Writing–original draft: Navid Omidkhoda. Competing Interests The authors declare that they have no conflict of interest. Ethical Approval The Ethics Committee of Mashhad University of Medical Sciences approved the study (IR.MUMS.MEDICAL.REC.1400.282) and was registered in the Iranian Registry of Clinical Trials (IRCT20201121049457N1). Funding This work was supported by the Mashhad University of Medical Sciences.

1. Taylor HS, Pal L, Sell E. Speroff’s Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins; 2019. 2. Macer ML, Taylor HS. Endometriosis and infertility: a review of the pathogenesis and treatment of endometriosis-associated infertility. Obstet Gynecol Clin North Am. 2012;39(4):535-49. doi: 10.1016/j.ogc.2012.10.002. 3. Mowers EL, Lim CS, Skinner B, Mahnert N, Kamdar N, Morgan DM, et al. Prevalence of endometriosis during abdominal or laparoscopic hysterectomy for chronic pelvic pain. Obstet Gynecol. 2016;127(6):1045-53. doi: 10.1097/ aog.0000000000001422. 4. Hickey M, Ballard K, Farquhar C. Endometriosis. BMJ. 2014;348:g1752. doi: 10.1136/bmj.g1752. 5. Warzecha D, Szymusik I, Wielgos M, Pietrzak B. The impact of endometriosis on the quality of life and the incidence of depression-a cohort study. Int J Environ Res Public Health. 2020;17(10):3641. doi: 10.3390/ijerph17103641. 6. Bulun SE. Endometriosis. N Engl J Med. 2009;360(3):268-79. doi: 10.1056/NEJMra0804690. 7. Sinaii N, Cleary SD, Ballweg ML, Nieman LK, Stratton P. High rates of autoimmune and endocrine disorders, fibromyalgia, chronic fatigue syndrome and atopic diseases among women with endometriosis: a survey analysis. Hum Reprod. 2002;17(10):2715-24. doi: 10.1093/humrep/17.10.2715. 8. Sacco K, Portelli M, Pollacco J, Schembri-Wismayer P, Calleja-Agius J. The role of prostaglandin E2 in endometriosis. Gynecol Endocrinol. 2012;28(2):134-8. doi: 10.3109/09513590.2011.588753. 9. Bulletti C, De Ziegler D, Polli V, Del Ferro E, Palini S, Flamigni C. Characteristics of uterine contractility during menses in women with mild to moderate endometriosis. Fertil Steril. 2002;77(6):1156-61. doi: 10.1016/s0015-0282(02)03087-x. 10. Ferrero S, Barra F, Leone Roberti Maggiore U. Current and emerging therapeutics for the management of endometriosis. Amirian et al Journal of Kerman University of Medical Sciences. 2025;32:38208 Drugs. 2018;78(10):995-1012. doi: 10.1007/s40265-018- 0928-0. 11. Becker CM, Gattrell WT, Gude K, Singh SS. Reevaluating response and failure of medical treatment of endometriosis: a systematic review. Fertil Steril. 2017;108(1):125-36. doi: 10.1016/j.fertnstert.2017.05.004. 12. Shi J, Tan X, Feng G, Zhuo Y, Jiang Z, Banda S, et al. Research advances in drug therapy of endometriosis. Front Pharmacol. 2023;14:1199010. doi: 10.3389/fphar.2023.1199010. 13. Whelan AM, Jurgens TM, Naylor H. Herbs, vitamins and minerals in the treatment of premenstrual syndrome: a systematic review. Can J Clin Pharmacol. 2009;16(3):e407-29. 14. Bahrami A, Ferns GA. Effect of curcumin and its derivates on gastric cancer: molecular mechanisms. Nutr Cancer. 2021;73(9):1553-69. doi: 10.1080/01635581.2020.1808232. 15. Bahrami A, Majeed M, Sahebkar A. Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition. Cell Oncol (Dordr). 2019;42(4):405-21. doi: 10.1007/s13402-019- 00442-2. 16. Bahrami A, Sadeghnia HR, Tabatabaeizadeh SA, Bahrami- Taghanaki H, Behboodi N, Esmaeili H, et al. Genetic and epigenetic factors influencing vitamin D status. J Cell Physiol. 2018;233(5):4033-43. doi: 10.1002/jcp.26216. 17. Yuxue J, Ran S, Minghui F, Minjia S. Applications of nanomaterials in endometriosis treatment. Front Bioeng Biotechnol. 2023;11:1184155. doi: 10.3389/ fbioe.2023.1184155. 18. Lopresti AL, Hood SD, Drummond PD. Multiple antidepressant potential modes of action of curcumin: a review of its anti-inflammatory, monoaminergic, antioxidant, immune- modulating and neuroprotective effects. J Psychopharmacol. 2012;26(12):1512-24. doi: 10.1177/0269881112458732. 19. Schulz KF, Altman DG, Moher D. CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials. BMJ. 2010;340:c332. doi: 10.1136/bmj.c332. 20. Rahimi HR, Jaafari MR, Mohammadpour AH, Abnous K, Ghayour Mobarhan M, Ramezanzadeh E, et al. Curcumin: reintroduced therapeutic agent from traditional medicine for alcoholic liver disease. Asia Pac J Med Toxicol. 2015;4(1):25- 30. doi: 10.22038/apjmt.2015.3983. 21. Gupta S, Agarwal A, Krajcir N, Alvarez JG. Role of oxidative stress in endometriosis. Reprod Biomed Online. 2006;13(1):126-34. doi: 10.1016/s1472-6483(10)62026-3. 22. Gazvani R, Templeton A. Peritoneal environment, cytokines and angiogenesis in the pathophysiology of endometriosis. Reproduction. 2002;123(2):217-26. doi: 10.1530/ rep.0.1230217. 23. Gupta SC, Sung B, Kim JH, Prasad S, Li S, Aggarwal BB. Multitargeting by turmeric, the golden spice: from kitchen to clinic. Mol Nutr Food Res. 2013;57(9):1510-28. doi: 10.1002/ mnfr.201100741. 24. Harris T, Vlass AM. Can herbal medicines improve cellular immunity patterns in endometriosis? Med Aromat Plants. 2015;4(2):184. doi: 10.4172/2167-0412.1000184. 25. Zhang Y, Cao H, Yu Z, Peng HY, Zhang CJ. Curcumin inhibits endometriosis endometrial cells by reducing estradiol production. Iran J Reprod Med. 2013;11(5):415-22. 26. Jana S, Paul S, Swarnakar S. Curcumin as anti-endometriotic agent: implication of MMP-3 and intrinsic apoptotic pathway. Biochem Pharmacol. 2012;83(6):797-804. doi: 10.1016/j. bcp.2011.12.030. 27. Kunnumakkara AB, Anand P, Aggarwal BB. Curcumin inhibits proliferation, invasion, angiogenesis and metastasis of different cancers through interaction with multiple cell signaling proteins. Cancer Lett. 2008;269(2):199-225. doi: 10.1016/j. canlet.2008.03.009. 28. Saydmohammed M, Joseph D, Syed V. Curcumin suppresses constitutive activation of STAT-3 by up-regulating protein inhibitor of activated STAT-3 (PIAS-3) in ovarian and endometrial cancer cells. J Cell Biochem. 2010;110(2):447- 56. doi: 10.1002/jcb.22558. 29. Singh M, Singh N. Curcumin counteracts the proliferative effect of estradiol and induces apoptosis in cervical cancer cells. Mol Cell Biochem. 2011;347(1-2):1-11. doi: 10.1007/ s11010-010-0606-3. 30. McLaren J, Prentice A, Charnock-Jones DS, Smith SK. Vascular endothelial growth factor (VEGF) concentrations are elevated in peritoneal fluid of women with endometriosis. Hum Reprod. 1996;11(1):220-3. doi: 10.1093/oxfordjournals. humrep.a019023. 31. Rocha AL, Reis FM, Taylor RN. Angiogenesis and endometriosis. Obstet Gynecol Int. 2013;2013:859619. doi: 10.1155/2013/859619. 32. Jana SK, Chakravarty B, Chaudhury K. Letrozole and curcumin loaded-PLGA nanoparticles: a therapeutic strategy for endometriosis. J Nanomedine Biotherapeutic Discov. 2014;4(1):123. doi: 10.4172/2155-983X.1000123. 33. Yun-Fei Q, Shu-Juan L, Bin L. Estrogen-independent inhibition of curcumin on formation of endometriotic foci in rats with experimental endometriosis. Med J West China. 2012;5:24. 34. Zhang Y, Cao H, Hu YY, Wang H, Zhang CJ. Inhibitory effect of curcumin on angiogenesis in ectopic endometrium of rats with experimental endometriosis. Int J Mol Med. 2011;27(1):87-94. doi: 10.3892/ijmm.2010.552. 35. Burney RO, Giudice LC. Pathogenesis and pathophysiology of endometriosis. Fertil Steril. 2012;98(3):511-9. doi: 10.1016/j. fertnstert.2012.06.029. 36. Bannuru RR, Osani MC, Al-Eid F, Wang C. Efficacy of curcumin and Boswellia for knee osteoarthritis: Systematic review and meta-analysis. Semin Arthritis Rheum. 2018;48(3):416-29. doi: 10.1016/j.semarthrit.2018.03.001. 37. Pourhabibi-Zarandi F, Shojaei-Zarghani S, Rafraf M. Curcumin and rheumatoid arthritis: a systematic review of literature. Int J Clin Pract. 2021;75(10):e14280. doi: 10.1111/ijcp.14280. 38. Kim KH, Lee EN, Park JK, Lee JR, Kim JH, Choi HJ, et al. Curcumin attenuates TNF-α-induced expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and proinflammatory cytokines in human endometriotic stromal cells. Phytother Res. 2012;26(7):1037-47. doi: 10.1002/ ptr.3694. 39. Chowdhury I, Banerjee S, Driss A, Xu W, Mehrabi S, Nezhat C, et al. Curcumin attenuates proangiogenic and proinflammatory factors in human eutopic endometrial stromal cells through the NF-κB signaling pathway. J Cell Physiol. 2019;234(5):6298- 312. doi: 10.1002/jcp.27360. 40. Peng Y, Ao M, Dong B, Jiang Y, Yu L, Chen Z, et al. Anti- inflammatory effects of curcumin in the inflammatory diseases: status, limitations and countermeasures. Drug Des Devel Ther. 2021;15:4503-25. doi: 10.2147/dddt.S327378. 41. Soetikno V, Sari FR, Lakshmanan AP, Arumugam S, Harima M, Suzuki K, et al. Curcumin alleviates oxidative stress, inflammation, and renal fibrosis in remnant kidney through the Nrf2-keap1 pathway. Mol Nutr Food Res. 2013;57(9):1649- 59. doi: 10.1002/mnfr.201200540. 42. Khayat S, Fanaei H, Kheirkhah M, Behboodi Moghadam Z, Kasaeian A, Javadimehr M. Curcumin attenuates severity of premenstrual syndrome symptoms: a randomized, double- blind, placebo-controlled trial. Complement Ther Med. 2015;23(3):318-24. doi: 10.1016/j.ctim.2015.04.001. 43. Arabnezhad L, Mohammadifard M, Rahmani L, Majidi Z, Ferns GA, Bahrami A. Effects of curcumin supplementation on vitamin D levels in women with premenstrual syndrome Journal of Kerman University of Medical Sciences. 2025;32:3820 9 Curcumin and intensity of dysmenorrhea in endometriosis patients and dysmenorrhea: a randomized controlled study. BMC Complement Med Ther. 2022;22(1):19. doi: 10.1186/s12906- 022-03515-2. 44. Bahrami A, Zarban A, Rezapour H, Agha Amini Fashami A, Ferns GA. Effects of curcumin on menstrual pattern, premenstrual syndrome, and dysmenorrhea: a triple- blind, placebo-controlled clinical trial. Phytother Res. 2021;35(12):6954-62. doi: 10.1002/ptr.7314. 45. Hesami S, Kavianpour M, Rashidi Nooshabadi M, Yousefi M, Lalooha F, Khadem Haghighian H. Randomized, double- blind, placebo-controlled clinical trial studying the effects of Turmeric in combination with mefenamic acid in patients with primary dysmenorrhoea. J Gynecol Obstet Hum Reprod. 2021;50(4):101840. doi: 10.1016/j.jogoh.2020.101840. 46. Karck U, Reister F, Schäfer W, Zahradnik HP, Breckwoldt M. PGE2 and PGF2 alpha release by human peritoneal macrophages in endometriosis. Prostaglandins. 1996;51(1):49- 60. doi: 10.1016/0090-6980(95)00159-x. 47. Vodouhe MV, Imorou RS, Atade R, Salifou K, Vignonzan U, Hounkponou NF, et al. Prevalence and factors associated with dysmenorrhea in Parakou, Benin. Open J Obstet Gynecol. 2020;10(8):1000-10. doi: 10.4236/ojog.2020.1080095.