A breakthrough in infection prevention using glycerol monolaurate (GML) gel derived from natural sources
Every year, millions of patients undergoing surgery face an invisible threat: pathogenic bacteria that can cause devastating infections at their incision sites.
The situation has grown increasingly dire as antibiotic-resistant bacteria like MRSA continue to evolve, while many pathogens hide within impenetrable bacterial biofilms that render conventional antibiotics useless 1 .
But what if we could apply a simple gel to surgical sites that not only kills these resilient pathogens on contact but also prevents the inflammation that complicates healing? Emerging research suggests we can—by harnessing the power of a natural compound found in coconut oil.
Glycerol Monolaurate (GML) is a fatty acid monoester that might sound complex but is quite familiar. It's a natural compound found in coconut oil and human breast milk, and the U.S. Food and Drug Administration (FDA) has long recognized it as "Generally Recognized As Safe" (GRAS) for use in cosmetics and food products 1 8 .
For decades, it has served as an emulsifier and preservative in everything from lotions to baked goods.
Scientists had discovered that GML possesses remarkable antimicrobial properties, particularly against Gram-positive bacteria like Staphylococcus aureus (including MRSA). It works by interfering with bacterial signal transduction systems—essentially disrupting the microbes' ability to communicate and produce toxins 1 .
Research has shown that GML can even eliminate pre-formed S. aureus biofilms at concentrations that don't inhibit bacterial growth, suggesting a unique mechanism of action separate from outright killing 1 .
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However, GML had significant limitations. Its solubility constraints meant it couldn't be easily delivered in effective concentrations, and it showed limited effectiveness against Gram-negative pathogens like Pseudomonas aeruginosa and Escherichia coli, which possess a protective outer lipopolysaccharide (LPS) layer that blocks GML's action 1 6 . This is where the innovative delivery system comes in.
The breakthrough came when researchers asked a simple question: What if we could deliver GML in a way that bypasses its solubility issues and enhances its antimicrobial effects?
The answer was a non-aqueous (NA) gel vehicle specifically designed to optimize GML's performance 1 .
This specialized gel accomplishes two critical functions:
To understand how researchers demonstrated the effectiveness of this GML gel, let's examine a comprehensive study published in PLoS ONE that tested both its laboratory and real-world efficacy 1 5 .
The research team, led by Mueller and Schlievert, designed a multi-phase experiment to thoroughly evaluate the GML gel's potential:
They collected a "rogues' gallery" of significant pathogens, including both Gram-positive and Gram-negative strains 1 5 .
Researchers exposed planktonic (free-floating) bacteria and pre-formed biofilms to the 5% GML Gel, then measured bacterial viability over time.
The team created subcutaneous incisions in New Zealand white rabbits, closed them with sutures, painted bacterial strains onto the incision sites, and then applied either the GML Gel or a placebo gel. They then monitored bacterial survival and inflammation signs 5 .
The laboratory results were striking. The 5% GML Gel demonstrated rapid bactericidal activity against all tested strains—both Gram-positive and Gram-negative—in broth cultures in less than 1 hour. Even more impressive was its effect on biofilms, which are typically resistant to antibiotics: the gel eliminated all viable biofilm bacteria within 4 hours 5 .
| Bacterial Type | Strain | Time to Eradication (Broth) | Time to Eradication (Biofilm) |
|---|---|---|---|
| Gram-positive | S. aureus MN8 | <1 hour | <4 hours |
| Gram-positive | S. aureus USA300 (MRSA) | <1 hour | <4 hours |
| Gram-negative | P. aeruginosa | <1 hour | <4 hours |
| Gram-negative | A. baumannii | <1 hour | <4 hours |
| Gram-negative | K. pneumoniae | <1 hour | <4 hours |
| Treatment Group | Bacterial Recovery | Visible Inflammation |
|---|---|---|
| 5% GML Gel | No detectable bacteria | Significantly reduced |
| Placebo Gel | High bacterial counts | Prominent redness and swelling |
Perhaps most remarkably, subsequent research discovered that this GML gel formulation could even kill bacterial spores from Bacillus and Clostridium species—including C. difficile—which are among the most difficult microbial forms to eradicate 2 .
| Bacterial Species | Spore Type | Time to Complete Elimination |
|---|---|---|
| B. subtilis | Bacillus spores | 1 hour |
| B. anthracis | Bacillus spores | 8 hours |
| C. difficile | Clostridium spores | 4 hours |
The remarkable effectiveness of the GML gel comes from its multiple mechanisms of action:
GML inserts itself into bacterial membranes, interfering with membrane protein function and potentially reducing the electrical potential across the membrane 2 . The non-aqueous vehicle enhances this effect by helping to disrupt the protective LPS layer of Gram-negative bacteria.
The gel appears to break down the extracellular matrix of biofilms, allowing GML to penetrate and kill the embedded bacteria 1 .
Beyond its direct antimicrobial effects, GML reduces the production of inflammatory chemokines (like IL-8 and MIP-3α) by human epithelial cells, helping to control the harmful inflammation that often worsens tissue damage during infections 4 .
This multi-targeted approach makes it exceptionally difficult for bacteria to develop resistance, as they would need to simultaneously overcome multiple distinct mechanisms of action.
The potential applications for GML gel extend far beyond surgical site protection.
A 2025 study demonstrated that monolaurin effectively inhibits antibiotic-resistant Staphylococcus aureus in patients with atopic dermatitis, with a minimal inhibitory concentration of just 2 μg/mL and no cytotoxicity to skin cells 8 .
An analog of GML called glycerol dithionomonolaurate (NB2) has shown enhanced activity against challenging fungal pathogens like Candida auris, while sparing beneficial lactobacilli of the normal microbiome 4 .
The ability of GML gel to kill persistent bacterial spores suggests potential use for disinfecting healthcare environments contaminated with organisms like C. difficile 2 .
A surprising 2025 discovery found that when bound to human serum albumin, GML's activity against multidrug-resistant Gram-negative pathogens was significantly enhanced, opening new avenues for systemic treatment approaches 6 .
The ongoing development of GML analogs that are resistant to bacterial degradation (like NB2, which isn't inactivated by staphylococcal lipase) promises even more effective future formulations 4 .
The transformation of a simple coconut oil derivative into a potent, broad-spectrum antimicrobial gel represents exactly the kind of innovative thinking needed in an era of rising antibiotic resistance.
By solving GML's delivery challenges through a non-aqueous gel system, scientists have unlocked a powerful tool that acts not only against a wide range of pathogens but also against the biofilms and inflammatory responses that make infections so difficult to treat.
What makes this approach particularly promising is its multi-targeted mechanism—making resistance development unlikely—combined with the excellent safety profile of a compound already deemed safe for human consumption.
In the endless arms race between humans and microbes, it's comforting to know that sometimes the most powerful solutions come not from complex chemical synthesis, but from cleverly enhancing the natural defenses we've had all along.
As research progresses, we may soon see GML-based gels deployed in hospitals, clinics, and perhaps even homes as a first line of defense against dangerous pathogens.