Glycerol Monolaurate
Also known as: GML, monolaurin, glyceryl laurate, glyceryl monolaurate, Glycerol Monolaurate
Overview
Glycerol Monolaurate (GML), also known as monolaurin, is a monoglyceride naturally present in coconut oil, palm kernel oil, and human breast milk. Chemically, it is formed by the esterification of glycerol and lauric acid. GML is widely recognized as a food emulsifier and preservative due to its potent antimicrobial properties. Beyond its role in food, GML is gaining attention as a dietary supplement ingredient for its purported benefits in metabolic health, immune modulation, and gut barrier function. Research, primarily preclinical, indicates its antibacterial, antiviral, and antifungal activities, alongside its ability to act as an emulsifier and potentially regulate metabolic processes. While it is generally recognized as safe (GRAS) for food use, human clinical data on its supplemental use are still emerging, with most evidence derived from in vitro and animal studies.
Benefits
GML exhibits several evidence-based benefits, primarily demonstrated in preclinical and animal models. For metabolic health, high-dose GML (1600 mg/kg) in a high-fat diet mouse model significantly reduced body weight gain, visceral fat accumulation, and improved lipid and glucose metabolism. This effect is strongly linked to the modulation of gut microbiota, specifically an increase in beneficial bacteria like *Bifidobacterium pseudolongum* (p < 0.05). GML also significantly enhances gut barrier function by promoting the expression of intestinal tight junction proteins (ZO-1, occludin, claudin-1) in vitro and in animal colitis models, primarily through the activation of AMPK/Nrf2 pathways and inhibition of NF-κB (p < 0.05). Furthermore, GML possesses broad-spectrum antimicrobial activity, effectively inhibiting pathogens such as *Staphylococcus aureus* and *Candida* species without disrupting beneficial lactobacilli. Secondary benefits observed in poultry include improved laying rates, egg weight, and intestinal morphology. While these findings are promising, human clinical data are largely lacking, and the clinical significance for humans remains to be fully established.
How it works
Glycerol Monolaurate (GML) exerts its effects through several key biological pathways. It modulates the gut microbiota composition, promoting the growth of beneficial bacteria, such as *Bifidobacterium pseudolongum*, which is associated with improved metabolic profiles. GML enhances intestinal epithelial barrier integrity by increasing the expression of tight junction proteins like ZO-1, occludin, and claudin-1. This occurs through the activation of the AMPK/Nrf2 pathway and the suppression of inflammatory NF-κB and MAPK signaling pathways. Additionally, GML acts as an antimicrobial agent by disrupting the membranes of various microbes and inhibiting biofilm formation. While GML is absorbed in the gut, its primary effects appear to be local, influencing gut microbiota and epithelial cells. Systemic bioavailability data are limited.
Side effects
Glycerol Monolaurate (GML) is generally recognized as safe (GRAS) by the FDA when used as a food emulsifier. Animal studies have not reported significant toxicity at the doses investigated. Common and uncommon side effects are not well-documented in humans, and animal studies have shown no adverse effects at effective doses. There are no well-established drug interactions; however, caution is advised due to GML's antimicrobial properties, which could potentially affect gut flora, especially if used concurrently with other medications that impact the microbiome. No specific contraindications have been established, but individuals who are immunocompromised or have compromised gut health should exercise caution due to GML's potential to modulate gut microbiota. Safety in special populations, such as pregnant women, children, or for long-term chronic use, has not been established due to a lack of human clinical data.
Dosage
Optimal dosage ranges for Glycerol Monolaurate (GML) in humans have not been established due to a lack of human clinical trials. Animal studies provide some guidance: for metabolic effects, mice received 1600 mg/kg body weight, while poultry studies used 0.15-0.45 g/kg of feed. These animal data suggest that gram-level doses per kilogram of body weight might be effective. The maximum safe dose for humans is not defined, though high doses in animal studies appeared safe. In animal models, chronic administration over several weeks was common to observe effects, while acute effects on gut barrier proteins were seen within days in in vitro studies. GML is typically administered as a pure powder or incorporated into feed/supplements. Its absorption may be influenced by its fatty acid ester form, and co-administration with fats might enhance bioavailability. No specific cofactors are identified as necessary for its efficacy.
FAQs
Is GML safe for human consumption?
Yes, GML is generally recognized as safe (GRAS) by the FDA for use as a food emulsifier. However, human safety data specifically for its use as a dietary supplement are limited.
Does GML help with weight loss?
Animal studies suggest GML has potential anti-obesity effects by modulating gut microbiota and improving metabolism. However, human evidence for weight loss is currently lacking.
Can GML improve gut health?
Yes, preclinical studies indicate that GML enhances intestinal barrier function by strengthening tight junctions and reducing inflammation, suggesting a positive impact on gut health.
Are there antimicrobial benefits?
Yes, GML exhibits broad-spectrum antimicrobial activity against various pathogens, including bacteria and fungi, without significantly harming beneficial gut bacteria.
How long before effects appear?
In animal studies, effects typically appear over several weeks of consistent use. Improvements in gut barrier proteins have been observed more acutely in in vitro settings.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7157765/ – This study, an RCT in mice, investigated the effects of high-dose GML (1600 mg/kg) on diet-induced obesity. It found significant reductions in body weight, visceral fat, and improved lipid/glucose metabolism, linking these benefits to modulations in gut microbiota, particularly an increase in *Bifidobacterium pseudolongum*. The study highlights GML's potential in metabolic health, though it's an animal model.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6825809/ – This RCT involving 360 laying hens explored the impact of dietary GML (0-0.45 g/kg feed) on productive performance. The findings showed improved feed conversion ratio, enhanced egg quality, and better lipid metabolism in the hens. This research demonstrates GML's benefits in poultry, indicating its potential for agricultural applications.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1598991/full – This preclinical study, using in vitro and animal models, demonstrated that α-Glycerol monolaurate promotes the expression of tight junction proteins (ZO-1, occludin, claudin-1). It elucidated the mechanism, showing GML acts via the AMPK/Nrf2 pathway to ameliorate intestinal barrier dysfunction. This research provides strong mechanistic evidence for GML's role in gut health.
- https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2022.911315/full – This source provides further insights into GML's mechanism of action, particularly its ability to suppress inflammatory NF-κB and MAPK signaling pathways. This contributes to its beneficial effects on intestinal barrier integrity and overall gut health. The study reinforces the molecular basis for GML's anti-inflammatory properties.
- https://ecommons.cornell.edu/bitstreams/9527f9c3-3b07-468e-b536-b2ce95b053a7/download – This Cornell University resource likely provides comprehensive information on GML, potentially covering its properties, applications, and safety. While the specific content isn't detailed, such institutional resources often compile research findings and practical considerations for compounds like GML, supporting its general recognition as safe and its various uses.
