The effect of resveratrol supplementation on obesity indices: a critical umbrella review of interventional meta-analyses

Abstract

Objective

Despite several studies assessing the impact of resveratrol on obesity indices, previous meta-analyses show conflicting results. Therefore, we conducted this critical umbrella review of interventional meta-analyses on the effect of resveratrol supplementation on body mass index (BMI), body weight (BW), waist circumference (WC), and body fat.

Methods

Searches were conducted across multiple databases to identify all relevant meta-analyses up to September 30th, 2025. Reported pooled effect sizes (ESs) and 95% confidence intervals (CIs) were extracted from each included study and synthesized using a random-effects model. Methodological quality was assessed using the AMSTAR 2 tool.

Results

Ultimately, 18 meta-analyses were included, with results showing a small but statistically significant reduction in BW (ES: − 0.18 kg, 95% CI − 0.32 to − 0.03, p = 0.02), BMI (ES: − 0.14 kg/m², 95% CI − 0.2 to − 0.08, p < 0.001), WC (ES − 0.43 cm, 95% CI − 0.64 to − 0.22, p < 0.001), and body fat (ES: − 0.3 kg, 95% CI − 0.48 to − 0.12, p = 0.001) in the resveratrol group compared to the control group, with subgroup analysis revealing statistical significance only in subgroups with doses > 400 mg/day and study duration ˃ 12 weeks.

Conclusion

Our review confirms that resveratrol supplementation reduces BW, BMI, WC, and body fat, particularly on doses > 400 mg/day and interventions lasting ˃12 weeks, with small effect sizes. Based on our findings, resveratrol supplementation could be considered as a complementary therapy in the management of obesity.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40519-025-01800-w.

Introduction

Obesity, the accumulation of excess fat in the body, is a major risk factor for multiple chronic diseases and has become an important healthcare concern due to its recent increase in prevalence [1, 2]. Currently, obesity is known to be the main risk factor for cardiovascular disease, including hypertension and heart failure [3–5]. The modern trend toward increased caloric intakes and lower levels of physical activity has been demonstrated to lead to weight gain [6]. Obesity exerts its effect on the whole human body, directly affecting the gastrointestinal, cardiovascular, nervous, and endocrine systems [7], causes the release of pro-inflammatory cytokines, accelerates aging and the onset of puberty, and has even been associated with increased mortality rates and shorter lifespans [8]. Furthermore, obesity also decreases quality of life, increases health-related costs, and has become a significant burden to healthcare systems globally [9, 10].

Literature evidence reports that nutraceuticals can have a positive effect on obesity [11]. One such nutraceutical is resveratrol, a natural polyphenol mainly found in peanuts, wine, berries, grapes, and nuts [12, 13] which has been associated with various health benefits due to its cardio-protective, anti-inflammatory, antioxidant, antihypertensive, and anticancer effects [14–16]. Various studies have assessed the impact of resveratrol supplementation on obesity, with conflicting results. A systematic review conducted in 2016 concluded that resveratrol does not have a significant impact on body mass index (BMI) and body weight (BW) [17], while a meta-analysis conducted in 2020 reported a decrease in BMI, waist circumference (WC), BW, and body fat [18], and then again a more recent meta-analysis did not result in a significant improvement in BMI [19]. Therefore, we conducted this critical umbrella review of interventional meta-analyses on the effect of resveratrol supplementation on obesity indices, namely BMI, BW, WC, and body fat, being, to our knowledge, the first umbrella review on the subject.

Methods

Search strategy and study selection

Searches were conducted on the Web of Science, Scopus, PubMed/Medline, and Embase databases using a combination of Medical Subject-Heading (MeSH) terms and pertinent keywords to collect all relevant articles up to September 30th, 2025. The details of this search process can be found in Supplementary Table 1. We did not consider any limitations based on language or publication date, and, additionally, we activated the PubMed/Medline email alert service to receive notifications about newly published manuscripts related to our research topic. Only peer-reviewed published meta-analyses were included; gray literature sources such as conference abstracts, dissertations, and preprints were not considered to maintain the methodological rigor and quality of the included evidence.

Eligibility criteria

In the present umbrella systematic review and meta-analysis, we incorporated meta-analyses on randomized controlled trials (RCTs) that assessed the influence of resveratrol on obesity indices, such as waist circumference (WC), body mass index (BMI), body weight (BW), and body fat mass. Our inclusion criteria encompassed meta-analyses that focused on resveratrol as an intervention, featured a clearly defined control group comprising individuals who did not receive resveratrol supplementation, and provided combined effect sizes for WC, BMI, BW, and/or body fat mass. Conversely, systematic reviews and meta-analyses that lacked sufficient data regarding the aforementioned obesity indices were excluded. Individual RCTs, letters to the editor, observational studies, and case reports were not considered within the scope of this review.

Data extraction

Four researchers autonomously gathered the following data from the selected papers: effect sizes (ESs) along with their associated confidence intervals (CIs), the publication year, the study’s sample size, the clinical trial duration, and the dose of resveratrol administered. Potential overlap among primary studies included in different meta-analyses was qualitatively assessed by comparing their lists of included trials. However, a formal quantitative overlap analysis (e.g., calculation of corrected covered area) was not feasible due to incomplete reporting of primary studies in several included reviews.

Quality assessment

Two reviewers independently assessed the methodological quality of the included articles using the Assessing the Methodological Quality of Systematic Reviews 2 (AMSTAR2) questionnaire [20]. In case of any discrepancies, the senior author was consulted to reach a consensus. The AMSTAR2 questionnaire consists of 16 items that are answered with "Yes", "Partial Yes", "No", or "Not a Meta-analysis". The AMSTAR2 checklist was classified into "Critically low quality", "Low quality", "Moderate quality", and "High quality".

Statistical analysis

The comprehensive meta-analysis was conducted using Stata software version 17, developed by Stata Corp. in College Station, Texas, USA. We extracted and summarized the pooled effect sizes (ESs) and 95% confidence intervals (CIs) reported in the included meta-analyses. Raw data from individual primary studies were not reanalyzed. To provide an overall synthesis and assess consistency across meta-analyses, we applied a random-effects model (DerSimonian and Laird method) using the reported pooled ESs. All ESs and CIs are presented rounded to two decimal places. In our statistical analysis, p-values were deemed statistically significant when they were lower than 0.05. To assess statistical heterogeneity among the arms, we used the Higgin’s I² statistic and the Pearson’s Chi-squared test (chi2). We regarded an I² value greater than 50% or a p-value less than 0.1 for the Q-test as indicative of substantial between-study heterogeneity [21]. In order to ensure the robustness of our overall findings, we conducted sensitivity analyses, systematically removing each meta-analysis one at a time and subsequently recalculating the final pooled effect size. In our pursuit of understanding the origin of this heterogeneity, we carried out subgroup analyses based on various factors, including the duration of the intervention and the average dosage of resveratrol administered. Furthermore, we employed funnel plots and the Egger’s tests to assess the potential of publication bias [22] and, when we publication bias was identified, we adjusted the effect sizes using the trim-and-fill test [23].

Results

Study selection

The search methodology successfully identified 2449 potentially pertinent research articles. After the elimination of duplicate entries, 1976 records remained. Out of these, 1948 were excluded based on the assessment of their titles and abstracts. Among the residual publications, 28 were excluded after an extensive evaluation of their full texts. Ultimately, 16 eligible publications, with a total of 18 meta-analyses, were included for analysis (Fig. 1) [18, 19, 24–36].

Fig. 1.

Flowchart of the study selection and inclusion process for the umbrella meta-analysis

Characteristics of the included studies

This umbrella review incorporated evidence from 19 published systematic reviews and meta-analyses of randomized controlled trials (RCTs) and controlled clinical trials (CCTs) evaluating the effects of supplementation on anthropometric outcomes. The publication years of the included meta-analyses ranged from 2017 to 2025, reflecting the most recent evidence available on this topic. Across these reviews, the number of included primary studies ranged from 2 to 25, with sample sizes varying between 112 and 1265 participants. The study populations were diverse, covering a wide range of clinical and non-clinical groups. Several reviews focused on patients with type 2 diabetes mellitus (T2DM), metabolic syndrome, polycystic ovarian syndrome (PCOS), or non-alcoholic fatty liver disease (NAFLD)/metabolic dysfunction-associated steatotic liver disease (MASLD). Others included individuals with obesity, overweight, or mixed populations from the general community with varying comorbidities. Participant mean ages ranged from the mid-20s to early 70s, and baseline BMI values were reported in some reviews, spanning from normal to obese categories (24.2–35.6 kg/m²). The duration of interventions ranged from approximately 5 to 32 weeks, reflecting both short- and medium-term supplementation trials. Reported daily dosages varied considerably across studies, from as low as 200 mg/day to over 1300 mg/day, depending on the specific intervention and targeted condition. The outcomes assessed were primarily anthropometric indices, including BW, BMI, WC, and, in some reviews, fat mass. Most reviews synthesized RCTs, while a few also included CCTs. Collectively, the evidence base is broad, encompassing diverse populations, intervention dosages, and study durations, thereby strengthening the comprehensiveness of this umbrella review while also highlighting heterogeneity in the included evidence. Detailed information regarding the characteristics of the included studies is available in Table 1. Table 2 provides an overview of the results of the risk of bias and methodological quality assessments for the publications included in the analysis.

Table 1.

Study characteristics of included studies

Citation (first author et al., year)	No. of studies in meta-analysis	Age range	Type of participants in meta-analysis	Type of studies included in meta-analysis	No. of participants in meta-analysis	Mean BMI	Study duration (weeks)	Intervention dosage (mg/day)	Outcomes
Lahouti (2025)	10	58	Patients with type 2 diabetes mellitus	Randomized controlled trials (RCTs)	586	24.2	13	646	BMI, WC, BW
Nemati (2023)	4	43	Patients with non-alcoholic fatty liver disease (NAFLD)	Randomized controlled trials (RCTs)	190	Not specified	11.5	826	BMI, WC, BW
Batista-Jorge (2024)	13	Not specified	General population with varying comorbidities	Randomized controlled trials (RCTs)	546	Not specified	9.6	619	WC
Zahoor (2024)	2	61	Individuals with obesity or overweight. The authors note that the majority of included participants were metabolically healthy	Randomized controlled trials (RCTs)	112	Not specified	5.5	200	BMI
Larik and Zahoor (2024)	3	38	Women with polycystic ovarian syndrome (PCOS)	Randomized controlled trials (RCTs)	169	26.1	13.7	1016	BMI
Huang and Zahoor (2024)	5	44	Individuals diagnosed with metabolic dysfunction-associated steatotic liver disease (MASLD)	Randomized controlled trials (RCTs)	216	Not specified	11.9	834	BMI
He and Zahoor (2023)	5	39–48	Patients diagnosed with non-alcoholic fatty liver disease (NAFLD)	Randomized controlled trials (RCTs)	216	Not specified	12	300–3000	BMI, WC, BW
Larik (2023)	3	28	Patients with polycystic ovarian syndrome (PCOS)	Randomized controlled trials (RCTs)	169	26.4	31.6	1066	BMI
Gu (2022)	5	59	Patients with type 2 diabetes mellitus	Randomized controlled trials (RCTs)	459	Not specified	14.8	607	WC
Zhou (2022)	15	51	General population with varying comorbidities	Controlled clinical trials	582	26.405	10.9	396	BW, BMI, WC, fat mass
Delpino (2021)	11	20 to 73	General population with varying comorbidities	Randomized controlled trials (RCTs)	447	Not specified	11.6	962	BW, BMI, WC
Rafiee (2021)	6	43	Patients with Non-alcoholic fatty liver disease	Randomized controlled trials (RCTs)	266	Not specified	13.3	1083	BW, BMI, WC
Zeraattalab-Motlagh, S. (a) (2021)	8	59.5	Patients with type 2 diabetes mellitus	Randomized controlled trials (RCTs)	506	29.8	16.2	329	BW, BMI, WC, fat mass
Zeraattalab-Motlagh, S. (b) (2021)	8	64	Patients with metabolic syndrome	Randomized controlled trials (RCTs)	325	27.7	18.5	418	BW, BMI, WC, fat mass
Zeraattalab-Motlagh (c) (2021)	5	45	Patients with Non-alcoholic fatty liver disease	Randomized controlled trials (RCTs)	216	31.4	14.2	1180	BW, BMI, WC
Tabrizi (2020)	25	54	General population with varying comorbidities	Randomized controlled trials (RCTs)	1127	29.9	12.1	568	BW, BMI, WC, fat mass
Mousavi (2019)	23	26.8–73.6	General population with varying comorbidities	Randomized controlled trials (RCTs)	1265	Not specified	12	300	BW, BMI, WC, fat mass
Elgebaly (2017)	4	45	Patients with Non-alcoholic fatty liver disease	Randomized controlled trials (RCTs)	158	35.6	14.7	1325	BW, BMI, WC

BMI: body mass index; BW: body weight; WC: waist circumference

Table 2.

Results of the methodological quality assessment of the meta-analyses

Study	A priori design	Selection and data extraction	Literature search	Publication type	List of studies	Characteristics of the included studies	Assessed scientific quality	Scientific quality formulating conclusions	Methods used to combine the findings	Assessed publication bias	Conflict of interest stated	Quality score
Lahouti (2025)	+	+	+	+	+	+	+	+	+	+	+	11
Nemati (2023)	+	+	+	+	+	+	+	+	+	+	+	11
Batista-Jorge (2024)	+	+	+	+	+	+	+	+	+	+	+	11
Zahoor (2024)	+	+	+	+	+	+	+	−	+	+	+	10
Larik and Zahoor (2024)	+	+	+	+	+	+	+	+	+	+	+	11
Huang and Zahoor (2024)	+	+	+	+	+	+	−	−	+	−	+	8
He and Zahoor (2023)	+	+	+	+	+	+	+	−	+	+	+	10
Larik (2023)	+	+	+	+	+	+	−	−	+	−	+	8
Gu (2022)	+	+	+	+	+	+	+	−	+	+	+	10
Zhou (2022)	+	+	+	+	+	+	+	−	+	+	+	10
Delpino (2021)	+	+	+	+	+	+	+	+	+	+	+	11
Rafiee (2021)	+	+	+	+	+	+	−	−	+	−	+	8
Zeraattalab-Motlagh S (a) (2021)	+	+	+	+	+	+	+	−	+	+	+	10
Zeraattalab-Motlagh (b) (2021)	+	+	+	+	+	+	+	−	+	+	+	10
Zeraattalab-Motlagh (c) (2021)	+	+	+	+	+	+	+	−	+	+	+	10
Tabrizi (2020)	+	+	+	+	+	+	+	+	+	+	+	11
Mousavi (2019)	+	+	+	+	+	+	+	+	+	+	+	11
Elgebaly (2017)	+	+	+	+	+	+	+	+	+	+	+	11

Findings from the meta-analysis

The effects of resveratrol supplementation on BW

Overall, 12 meta-analyses involving 5878 subjects examined the influence of resveratrol supplementation on BW, resulting in a small but statistically significant reduction in BW compared to the control (ES: − 0.18 kg, 95% CI − 0.32 to − 0.09, p = 0.02) (Fig. 2), with a low heterogeneity among the studies (I² = 47%, p = 0.04). Subgroup analyses only demonstrated a significant effect on body weight at dosages >400 mg/day (ES: − 0.17 kg, 95% CI − 0.29 to − 0.06, p = 0.002) and in interventions lasting ˃12 weeks (ES: − 0.21 kg, 95% CI − 0.33 to − 0.09, p = 0.001) (see Supplementary Fig. 1). On sensitivity analysis, no single study modified the overall outcome (see Supplementary Fig. 2). Furthermore, we found no evidence of publication bias when assessing the combined effect sizes through the funnel plot and Egger’s test (see Supplementary Fig. 3).

Fig. 2.

Forest plot of the umbrella review on the effects of resveratrol intervention on body weight. ES: effect size. CI: confidence interval

The effects of resveratrol supplementation on BMI

Overall, 16 meta-analyses including 6871 subjects studied the influence of resveratrol supplementation on BMI. After resveratrol administration, a small but statistically significant reduction in BMI was discovered (ES: − 0.14 kg/m², 95% CI − 0.2 to − 0.2, p < 0.001) (Fig. 3), with a low heterogeneity among the studies (I² = 0%, p = 0.59). Subgroup analyses only demonstrated a statistically significant effect on BMI on dosages >400 mg/day (ES: − 0.17 kg/m², 95% CI − 0.24 to − 0.09, p < 0.001) and interventions duration ˃12 weeks (ES: − 0.18 kg/m², 95% CI − 0.26 to − 0.01, p < 0.001) (see Supplementary Fig. 1). No single study affected the overall outcome on the sensitivity analysis (see Supplementary Fig. 2). Furthermore, we found no evidence of publication bias when assessing the combined effect sizes through the funnel plot and Egger’s test (see Supplementary Fig. 3).

Fig. 3.

Forest plot of the umbrella review on the effects of resveratrol intervention on body mass index. ES: effect size. CI: confidence interval

The effects of resveratrol supplementation on WC

Overall, 14 meta-analyses involving 4548 subjects reported the influence of resveratrol supplementation on WC, resulting in a small but statistically significant reduction in WC compared to the control (ES: − 0.43 cm, 95% CI − 0.64 to − 0.22, p < 0.001) (Fig. 4), with moderate, non-statistically significant heterogeneity among the studies (I² = 56.4%, p = 0.005). As with BW and BMI, subgroup analyses only demonstrated statistical significance on resveratrol supplementation at dosages > 400 mg/day (ES: − 0.53 cm, 95% CI − 0.83 to − 0.23, p < 0.001) and interventions lasting ˃12 weeks (ES: − 0.64 cm, 95% CI − 0.92 to − 0.37, p < 0.001) (see Supplementary Fig. 1). On sensitivity analysis, no single study modified the overall outcome (see Supplementary Fig. 2). Furthermore, we found no evidence of publication bias when assessing the combined effect sizes through the funnel plot and Egger’s test (see Supplementary Fig. 3).

Fig. 4.

Forest plot of the umbrella review on the effects of resveratrol intervention on waist circumference. ES: effect size. CI: confidence interval

The effects of resveratrol supplementation on body fat

Overall, five (n = 5) meta-analyses including a total of 1375 subjects studied the influence of resveratrol supplementation on body fat. After resveratrol administration, a small but statistically significant reduction in body fat mass was discovered (ES: − 0.3 kg, 95% CI − 0.48 to − 0.12, p = 0.001) (Fig. 5). The heterogeneity among the studies was not statistically significant (I² = 0%, p = 0.93). Subgroup analyses also demonstrated that resveratrol supplementation at dosages > 400 mg/day (ES: − 0.33 cm, 95% CI − 0.6 to − 0.06, p = 0.019) and interventions lasting ˃12 weeks (ES: − 0.28 cm, 95% CI − 0.48 to − 0.08, p = 0.001) resulted in a more pronounced effect on body fat mass reduction when compared to other subgroups (see Supplementary Fig. 1). No single study affected the overall outcome on the sensitivity analysis (see Supplementary Fig. 2). Furthermore, we found no evidence of publication bias when assessing the combined effect sizes through the funnel plot and Egger’s test (see Supplementary Fig. 3).

Fig. 5.

Forest plot of the umbrella review on the effects of resveratrol intervention on body fat mass. ES: effect size. CI: confidence interval

Discussion

Summary of principal findings

The current critical umbrella review of interventional meta-analyses on the effect of resveratrol supplementation on obesity indices (BW, BMI, WC and body fat) summarized the results of 18 meta-analyses. Our findings support the evidence that resveratrol supplementation decreases BW, BMI, WC, and body fat mass.

Interpretation of results

Several mechanisms have been proposed for resveratrol’s effect on weight loss. Some studies declare that resveratrol could exert an impact by instigating modifications on gene expression similar to those observed in calorie-restricted environments, helping regulate the metabolism of glycolipids by activating AMP-activated protein kinase (AMPK), increasing the concentrations of peroxisome proliferator-activated receptor gamma coactivator 1-alpha protein, and increasing the activity of citrate synthase, thus opposing some of the intracellular enzyme modifications produced by obesity [24, 37, 38]. In one trial, supplementation of 3 g of resveratrol daily for 12 weeks resulted in an increase in the gene expression of AMPK and sirtuin 1 in skeletal muscle, mimicking the effects induced by exercise [39]. Other studies have proposed an enhancement of lipolysis and an increase in energy expenditure through a thermogenic effect in brown adipose tissue [40, 41], an increase in satiety and a reduction in the resting metabolic rate [42], an inhibition of the differentiation of preadipocytes, reducing the proliferation of adipocytes, and the induction of apoptosis of adipocytes [43] as probable mechanisms by which resveratrol could reduce body fat. Since alterations in the microbiome activate brown adipose tissue and induce white adipose tissue browning [44], it has also been suggested that resveratrol’s anti-obesity effect might be caused by changes in the intestinal microbiome [45]. Evidence from human trials suggests that resveratrol may activate AMPK and SIRT1 signaling pathways, as shown by increased gene expression in skeletal muscle following supplementation [39]. These pathways are thought to mimic calorie restriction and promote energy metabolism. However, other proposed mechanisms, such as enhanced lipolysis and thermogenesis in brown adipose tissue, modulation of appetite, inhibition of adipocyte differentiation, and remodeling of the gut microbiota, are primarily derived from animal and in vitro studies and remain theoretical in humans. Therefore, while preclinical data provide valuable mechanistic insight, further clinical investigations are needed to confirm these effects in humans.

Comparison with previous literature

A previous meta-analysis showed similar results to our review, reporting a decrease in BW, BMI, and WC after resveratrol supplementation, with no reduction in fat mass [29], and Fogacci et al. further demonstrated that resveratrol at doses > 300 mg/day reduced cardiovascular disease risk in patients with obesity [46]. Our subgroup analyses demonstrated that resveratrol supplementation at dosages >400 mg/day and interventions lasting ˃12 weeks resulted in a more pronounced effect on reducing BW, BMI, WC, and body fat mass when compared to lower dosages or shorter interventions, while most of the latter subgroups failed to reach statistical significance. Similarly, according to Delpino et al., resveratrol does not result in a significant impact on BW or BMI, but produces a significant effect on WC in interventions lasting >12 weeks [28]. In contrast to our results, an older systematic review observed no significant effect of resveratrol on obesity indices; however, the authors concluded that, until 2015, further evidence was required before resveratrol supplementation could be recommended for the treatment of obesity [17]. In other studies, the administration of 500 mg of resveratrol thrice daily for 3 months resulted in a reduction of BW, BMI, and body fat mass in patients with metabolic syndrome [47], and, at a dose of 500 mg/day for 12 weeks, improved BW, BMI, and WC in overweight subjects with non-alcoholic fatty liver disease (NAFLD) [48], but a study using 3000 mg/day of resveratrol for 8 weeks in subjects with NAFLD did not result in a reduction in abdominal body fat [49], nor did 1000 mg/day of resveratrol produce a significant change in BW and BMI in patients with type 2 diabetes mellitus [50]. These conflicting results might be caused by variations in study population characteristics, their comorbidities, and the dose and duration of the resveratrol used by the studies. Our study provides evidence that higher doses and longer interventions increase resveratrol’s effectivity for weight loss, but further studies might be needed to determine the recommended dosage and duration of resveratrol supplementation.

Clinical implications

Our critical umbrella review of interventional meta-analyses revealed that resveratrol supplementation significantly reduced the obesity indices. Hence, resveratrol administration can be considered an alternative treatment for managing obesity. It should be noted that resveratrol at high doses (≥ 2.5g/day) may cause side effects like diarrhea, nausea, vomiting and liver abnormalities in NAFLD patients [51]. Further studies are needed to determine the recommended dosage and duration of resveratrol supplementation.

Clinical relevance

Although resveratrol supplementation produced statistically significant reductions in body weight, BMI, waist circumference, and body fat, the magnitude of these changes was small (e.g., < 0.5 kg for weight and < 0.2 kg/m² for BMI). Such modest effects are unlikely to translate into clinically meaningful improvements in obesity-related outcomes when used as a standalone intervention. Therefore, resveratrol should be considered as a complementary, rather than primary, strategy within a comprehensive obesity management plan that includes diet modification, physical activity, and behavioral interventions.

Strengths and limitations

The major strength of this critical umbrella review is that it is the first to synthesize evidence exclusively from interventional meta-analyses assessing the effects of resveratrol supplementation on obesity-related indices. Our study applied a rigorous methodological framework, including quality appraisal using the AMSTAR 2 tool and comprehensive subgroup analyses by dosage and intervention duration. Furthermore, no evidence of publication bias was observed, and heterogeneity was generally low to moderate across outcomes, enhancing the robustness of the findings.

Nonetheless, several limitations should be acknowledged. First, there is potential overlap of primary trials across the included meta-analyses, which may lead to an overestimation or duplication of evidence. Although we qualitatively examined overlap by comparing the included trial lists, a formal quantitative overlap analysis (e.g., corrected covered area) could not be performed due to incomplete reporting in some reviews. Second, there was substantial heterogeneity among study populations, as the included trials involved individuals with diverse metabolic and clinical backgrounds, including those with type 2 diabetes mellitus (T2DM), polycystic ovary syndrome (PCOS), non-alcoholic fatty liver disease (NAFLD), and metabolic syndrome, as well as healthy overweight or obese adults. Such variability may have influenced responsiveness to resveratrol and limits generalizability. Third, differences in baseline BMI values, intervention duration (ranging from approximately 5 to 32 weeks), and dosages (200–1300 mg/day) further contributed to between-study variability. Additionally, in several trials, resveratrol was administered alongside lifestyle interventions or standard pharmacologic therapies, making it difficult to isolate its independent effects. Finally, as with any umbrella review, the synthesis relied on aggregate data from published meta-analyses rather than individual participant data, which restricts the ability to explore dose–response effects or adjust for confounders at the patient level. Despite these limitations, this review provides a valuable and updated synthesis of the available interventional evidence on the impact of resveratrol supplementation on obesity indices.

Conclusion

The present critical umbrella review indicates that resveratrol supplementation is associated with small but statistically significant reductions in body weight, BMI, waist circumference, and body fat, particularly at doses above 400 mg/day and intervention durations longer than 12 weeks. However, given the modest magnitude of these effects and the heterogeneity among study populations, the clinical relevance remains uncertain. Further large-scale, high-quality randomized controlled trials are warranted to determine optimal dosing, duration, and long-term safety before resveratrol can be recommended for routine use in obesity management.

Supplementary Information

Below is the link to the electronic supplementary material.

Author contributions

AA-Z contributed to study conception, data validation, data analysis, study supervision, and manuscript writing. SAKS, HMA, AA, EK, NA, SJA, MAA, MAMA, and AMA contributed to literature review, data collection, data validation, data interpretation, and revision of the manuscript for editorial and intellectual contents. All authors read and approved the final draft of the manuscript.

Funding

None.

Availability of data and materials

All data are available within the manuscript and its supplemental files.

Code availability

None.

Declarations

Ethics approval and consent to participate

Not required as this research does not involve direct patient or animal contact.

Competing interests

The authors declare no competing interests.