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Results from animal studies and human clinical trials suggest that various probiotics may potentially benefit body-related, biochemical, and metabolic parameters associated with obesity (1). Animal studies revealed beneficial results in obese models whereas the results in humans are sparse and inconsistent (5). Bacteroides probiotics could be used for treating obesity (2). Esp., Bifidobacterium and Lactobacillus strains are still the most widely used probiotics in functional foods and dietary supplements, but next generation probiotics, such as Faecalibacterium prausnitzii, Akkermansia muciniphila, or Clostridia strains, have demonstrated promising results (11).
A systematic review and meta-analysis (16), identified by the code CRD420251123057, examined the effects of probiotic supplementation on body weight, BMI, waist circumference and body fat percentage. This study included 12 randomized clinical trials (RCTs) with a combined total of 931 participants from East Asia. The analysis incorporated studies conducted up to August 2025.
The study demonstrated that probiotics effectively improve several health metrics in obese patients:
However, probiotics did not significantly affect:
Among the regimens studied, those using single strains at high doses (≥1 × 10^10 CFU/day) or combined with health guidance showed more pronounced effects in individuals with simple obesity.
A systematic review and meta-analysis, which included 62 papers and covered research up to June 2023, examined the effects of probiotics supplementation on overweight and obesity indicators. The findings revealed that consuming probiotics in amounts ranging from 1.0 × 10^4 to 1.35 × 10^15 CFU per day for periods between 2 to 104 weeks showed significantly reduced weight, BMI, WC, BF%, and BFM across most studies (21).
A systematic review (4) examined the effects of probiotic and synbiotic supplementation on weight loss in people with overweight and obesity. This study included 27 randomized clinical trials (RCTs) with a combined total of 2413 participants. The analysis incorporated studies conducted up to September 2021.
The study demonstrated the use of fermented foods as a source of probiotics, primarily containing lactic acid bacteria (LAB) from the genera Lacticaseibacillus Lactiplantibacillus, Lactobacillus, Latilactobacillus, and Bifidobacterium.
There was significant diversity in the probiotic species and strains used to address overweight and obesity. Most studies detailed the probiotic or symbiotic formulations at the strain level, employing either multi-strain or single-strain approaches.
When single-strain probiotics were used, all interventions showed positive effects in reducing body weight, BMI, waist circumference, body fat mass, or fat percentage. The effective strains included:
Lactobacillus
Bifidobacterium
Pediococcus
The dosage and duration of probiotic interventions varied significantly. The maximum dose administered was 5 × 10^10^, while the minimum was 1 × 10^6^. The duration of these studies ranged from 4 to 36 weeks.
A systematic review and meta-analysis (13), identified by the code CRD42020183136, examined the effects of probiotic supplementation on various health metrics. This study included 26 randomized clinical trials (RCTs) with a combined total of 1720 participants. The research focused on the impact of probiotics on body weight, body mass index (BMI), waist circumference (WC), fat mass, tumor necrosis factor-alfa insulin levels, total cholesterol, and LDL cholesterol. The analysis incorporated studies conducted up to December 2020.
The study demonstrated significant effects in various health parameters when compared to control groups. The key findings are as follows:
Significant decreases in body weight, BMI, and WC were observed in studies utilizing both single and multi-bacterial species. Notably, reductions in body adiposity parameters were only evident in studies that administered a probiotic dose of ≥ 10^10 CFU for a duration of ≥8 weeks.
A systematic review and meta-analysis (3), which included six clinical trials (RCTs) with a total of 821 participants and nine preclinical animal studies, examined the effects of probiotic supplementation on body mass index (BMI), adiposity parameters, glucose, plasma lipid biomarkers, and gut hormones. This research covered studies up to April 2020. The findings indicated a positive association between the probiotic and placebo groups in terms of reducing BMI, total cholesterol, leptin, and adiponectin. Additionally, there were negative estimates for Fasting blood glucose (FBG) and CRP. Although clinical studies with data on positive microbiota modulatory capacities suggested that high doses of common single and multispecies of Lactobacillus and Bifidobacterium improved significant obesity-related parameters, the primary limitation was the high inter-study variability and the absence of standardized protocols.
A systematic review and meta-analysis (12), encompassing 12 randomized clinical trials (RCTs) with a total of 821 participants, investigated the impact of probiotic supplementation on body weight management, lipid profile, and glycemic control. This research spanned from January 2008 to July 2018.
The findings revealed that probiotic supplementation has been shown to significantly reduce several body metrics when compared to control groups. The findings include:
In addition to these body metrics, significant improvements were noted in metabolic parameters:
However, changes in the following parameters were not statistically significant:
Overall, probiotic supplementation appears to have a beneficial impact on body weight, BMI, waist circumference, fat mass, fat percentage, and several key metabolic parameters (12).
A systematic review and meta-analysis (15), identified by the code CRD42016052609, examined the effects of probiotic supplementation on body weight, body mass index (BMI), fat mass and fat percentage. This study included 15 randomized clinical trials (RCTs) with a combined total of 957 participants. The analysis incorporated studies conducted up to September 2016.
The study demonstrated that the administration of probiotics led to a significantly larger reduction in several key metrics compared to a placebo. These metrics include:
Despite these reductions, it is important to note that the effect sizes were small. Additionally, the effect of probiotics on fat mass was found to be non-significant, with a mean difference of -0.42 kg, a 95% confidence interval of [-1.08, 0.23] kg, and an I² of 84%.
The randomized clinical phase II treatment trial NCT04797442 revealed that the metabolic benefits of A. muciniphila supplementation might rely on its initial levels in the intestine, highlighting the possibility of using gut microbiota as a guide for probiotic supplementation (18).
Bifidobacterium adolescentis IVS-1 significantly influences ecological performance. This is likely because of competitive interactions with the existing microbiota. The results clearly indicated that the probiotic individually enhanced markers of colonic permeability. This provides a rationale for their use in conditions characterized by an underlying gut leakiness (19)
In the phase II trial NCT01978691 comparing Bifidobacterium animalis lactis 420 (B420), polydextrose, and their combination, the intention-to-treat results were inconclusive due to dropouts and non-compliance. Per-protocol findings suggest the need for larger trials, especially for those with impaired glucose levels.
The phase III trial NCT02921217 showed that Bifidobacterium animalis lactis BPL1 improves adiposity biomarkers in individuals with abdominal obesity, particularly women. The increase in the gut Akkermansia genus may be a mechanism involved, suggesting Bifidobacterium animalis lactis BPL1 as a complementary obesity management approach (14).
The trial NCT02355210 found that Bifidobacterium animalis lactis BB-12's ecological performance is significantly influenced by its "autochthony" rather than prebiotic addition. While synbiotic combinations lacked synergism, both probiotic and prebiotic components individually improved colonic permeability markers, supporting their use in conditions with gut leakiness.
For the effect of Bifidobacterium animalis lactis + Lactobacillus gasseri on adiposity / obesity no final published results were found as of February 2026
Bifidobacterium breve B-3 leads to a significant reduction in fat mass by the 12th week when compared to the placebo group. Furthermore, significant correlations were found between changes in specific blood parameters and the alterations in fat mass within the B-3 group (6).
The phase I/II trial NCT01870544 has no published data as of September 2025. The phase II trial NCT02962583 found that Lacticaseibacillus rhamnosus HA-114 supplementation can have positive metabolic and psychological effects in overweight individuals, but it did not enhance weight loss. And, in a non-randomized trial, Lacticaseibacillus rhamnosus supplementation showed no benefits for weight loss or body composition improvement. The observed BMI SDS reduction in both groups may be attributed to dietary improvements from nutritional advice.
For the effect of Lacticaseibacillus rhamnosus + Limosilactobacillus reuteri on adiposity / obesity no final published results were found as of September 2025
Lactobacillus delbrueckii bulgaricus reduced triglycerides, but not body weight, BMI, or body fat percentage (7)
The placebo-controlled, randomized, and double-blind trial XXX- Lactobacillus gasseri BNR17 & Adiposity / Obesity demonstrated that even without changes in behavior or diet, taking the BNR17 supplement resulted in weight loss and reduced waist and hip measurements. However, there were no significant differences between the placebo and probiotic groups. These findings indicate the necessity for a future, more comprehensive clinical study with a larger population (8)
The multicenter, double-blind, randomized, placebo-controlled intervention trial
XXX - Lactobacillus gasseri SBT2055 (LG2055) & Adiposity / Obesity revealed lowering effects on abdominal adiposity, body weight and other measures, suggesting its beneficial influence on metabolic disorders. It demonstrated a reduction in abdominal fat, body weight, and other metrics, indicating its positive impact on metabolic disorders (9).
For the double-blind, randomized clinical phase III treatment trial NCT04717726 no published results were found as of September 2025
There are only results from a preclinical mice study as of March 2026 showing an improvement of experimental obesity (9)
The intake of Pediococcus pentosaceus LP28 inactivated resulted in significant reductions in several body composition metrics when compared to a placebo group (10)
No large, definitive randomized controlled trials have confirmed its direct efficacy for fat loss or obesity treatment in human populations (17).
For the double-blind, randomized clinical trial NCT03115385 no published results were found as of September 2025
According to XXX - VSL#3 TM & Adiposity / Obesity, VSL#3 supplements appeared to provide some protection against weight gain and fat accumulation in healthy young men who were consuming a diet high in fat and energy (20)
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(7) Chu et al. 2024 Metabolites 14(2): 129
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(8) Jung et al. 2013 Korean J Fam Med 34: 80-9
(9) Molina-Tijeras et al. 2021 Pharmacol Res 167: 105471
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(17) Yadav et al. 2013 J Biol Chem 288(35): 25088-25097
(18) Zhang et al. 2025 Cell Metab 37(3): 592-605
(19) Krumbeck et al. 2018 Microbiome 6: 121
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see also:
Adiposity / Obesity & Drugs / Treatments
Nutritional Therapy & Adiposity / Obesity