Monolaurin

What monolaurin is

Monolaurin, chemically glycerol monolaurate (GML), is a monoglyceride: a glycerol molecule to which a single lauric acid is bound. Lauric acid is a fatty acid with twelve carbon atoms found mainly in coconut and palm kernel fat; more on medium-chain fats is on the page on MCT oil. Monolaurin itself occurs naturally in breast milk. A laboratory study measured around 3,000 µg/ml there, 150 µg/ml in cow’s milk and none in infant formula (Schlievert 2019).

Chemically, monolaurin belongs to the additive group E 471, the mono- and diglycerides of fatty acids, which are approved as emulsifiers in the EU. As a dietary supplement it is sold in capsules. In the BK-Score, human evidence stands at 2 out of 10 points. This axis rates the state of knowledge, not the substance: effective in the lab does not mean that a capsule does the same in the body.

How it is supposed to work

In laboratory experiments, monolaurin inhibits numerous bacteria, fungi and viruses with a lipid envelope; a 2019 literature review lists many such studies (Barker 2019). It also dampens inflammatory signals. In the rhesus monkey study by Li 2009, it slowed the signaling chain in the mucosa that attracts the immune cells the virus needs to spread.

In experiments with human T cells, monolaurin changed the order of the lipids in the cell membrane and thereby inhibited the activation of the cells and the production of several messenger substances (Zhang 2016). That is one reason why it is considered anti-inflammatory, and at the same time an open question for safety. Whether effective amounts reach the sites where pathogens reside after a capsule is swallowed has not been studied in humans.

What the studies show

Vaginal gel for bacterial vaginosis: no better than placebo

In a multicenter, double-blind study, Mancuso 2020 tested a 5 percent monolaurin gel against a placebo gel, twice daily for three days, in 109 women with bacterial vaginosis (73 monolaurin, 36 placebo). The primary endpoint, clinical cure according to all four Amsel criteria, was missed: 17 percent with monolaurin, 25 percent with placebo. The number of lactobacilli increased with monolaurin. Two thirds of both groups reported mild to moderate genital complaints, with no difference between the groups.

Nasal gel against staphylococci: small study without a control group

In 2020, Schlievert and Peterson had 40 healthy volunteers apply a 5 percent GML gel in the nose for three days. 14 of them carried Staphylococcus aureus in the nose beforehand. The bacterial count fell by three orders of magnitude; for S. aureus this lasted two to three days. There was no comparison group, and infections were not measured as a clinical endpoint.

Rhesus monkeys and SIV: the finding many refer to

In 2009, Li and colleagues showed in Nature that GML in the vagina protected rhesus monkeys from infection with SIV, the monkey relative of HIV, despite repeated high virus doses. That is an animal model with local application. It says nothing about intake as a capsule in humans.

Blood levels and COVID-19: an association

Sola 2025 measured the monolaurin level in the blood of 1,000 employees of a hospital in Novara and followed them for six months. Those with higher levels were infected with SARS-CoV-2 less often. This is an observational study: it shows an association, not proof that monolaurin taken orally protects.

Where the data stop

• Intake as a dietary supplement. A literature review found no peer-reviewed study on clinical use as a dietary supplement; all three papers with effects in humans concerned the vagina or the mouth (Barker 2019).
• Viruses, Candida and infections. This is what monolaurin is sold for. For none of these uses could a clinical study with oral intake be found. The laboratory results cannot be transferred as long as it is unclear what amounts reach the tissue after swallowing.
• Bacterial vaginosis. Here monolaurin was tested under controlled conditions and did not cure better than placebo.
• Gut flora. No studies on the effect on the human gut flora could be found; there are feeding trials in livestock.

Status, approval and legal

Monolaurin is not a medicine. Chemically it belongs to E 471, the mono- and diglycerides of fatty acids, which are approved as a food additive in the EU. Monolaurin has no entry in the European Commission’s Novel Food Catalogue, and no official classification as a novel food could be found; in Germany it is offered as a dietary supplement. There is no authorized health claim. Advertising with protection against infections or viruses is therefore not permitted.

Safety

There is no safety study in humans for intake as a capsule. From the gel studies it is only known that local application over a few days was tolerated without serious problems. In laboratory experiments, monolaurin inhibits the activation of human T cells; what this means with regular intake is unclear. In the BK-Score, safety data stand at 3 out of 10 points; this axis measures how well safety has been studied, not how safe the substance is. This text is information and does not replace medical advice.

Sources

• Barker LA et al., J Chiropr Med 2019 – literature review on the clinical use of monolaurin as a dietary supplement
• Mancuso AC et al., J Low Genit Tract Dis 2020 – 5 percent monolaurin vaginal gel for bacterial vaginosis, RCT with 109 women
• Schlievert PM, Peterson ML, mSphere 2020 – GML nasal gel against Staphylococcus aureus, 40 volunteers without a control group
• Li Q et al., Nature 2009 – GML prevents mucosal transmission of SIV in rhesus monkeys
• Schlievert PM et al., Sci Rep 2019 – GML and the antimicrobial effect of breast milk
• Zhang MS et al., Sci Rep 2016 – GML inhibits signaling and function of human T cells
• Sola D et al., Int J Mol Sci 2025 – monolaurin in the blood and COVID-19 risk, observational study with 1,000 employees
• European Commission, food additives database – E 471 mono- and diglycerides of fatty acids
• European Commission, Novel Food Catalogue (no entry for monolaurin, as of 10/2026)