Does coconut oil exhibit antibacterial properties?

Key points to remember.

Coconut oil has antibacterial properties chiefly associated with its high levels of lauric acid and monolaurin, capable of disrupting the membranes of certain bacteria, particularly Gram-positive ones such as Staphylococcus aureus.
Experimental studies also suggest activity against Cutibacterium acnes, a bacterium involved in acne.
On acne-prone skin, its occlusive and comedogenic properties may limit its usefulness, even though its isolated components demonstrate antibacterial activity in laboratory tests.
In oral health, coconut oil employed as a mouth rinse (“oil pulling”) has demonstrated a reduction in Streptococcus mutans comparable to that achieved with chlorhexidine.
Despite these promising findings, coconut oil does not replace clinically validated antiseptics or antibiotics, particularly in cases of confirmed infection.

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Does coconut oil exhibit antibacterial properties?

The coconut oil is a vegetable oil composed predominantly of medium-chain triglycerides, of which lauric acid constitutes approximately 45 to 50% of the lipid fraction. In addition to its nourishing effects, it possesses noteworthy antibacterial properties. These are primarily based on the presence of lauric acid and its derivative, monolaurin. Lauric acid can interact with the lipids constituting the bacterial membrane, causing an alteration of its structural integrity. This membrane disruption leads to increased cellular permeability, potentially resulting in lysis and bacterial death. This action appears particularly pronounced against Gram-positive bacteria such as Staphylococcus aureus, whose membrane structure renders them more vulnerable to this type of lipid attack.

Monolaurin, formed from lauric acid, also exhibits significant antimicrobial activity. It can penetrate the bacterial cell wall, disrupt cellular metabolism and impair membrane exchanges essential for the survival of the micro-organism. Other medium-chain fatty acids found in coconut oil, notably capric, caprylic and caproic acids, contribute to this activity by similarly targeting bacterial lipid membranes. Beyond this direct action, some scientific data suggest that coconut oil may exert an immunomodulatory effect by enhancing the phagocytic activity of macrophages, thus indirectly supporting antimicrobial defence.

The combination of these mechanisms—direct membrane disruption and modulation of the immune response—explains why coconut oil is being investigated as a natural antimicrobial agent. However, its effectiveness depends on the context of application, the concentration and the bacterial species targeted.

Oral health: coconut oil as a mouthwash?

The coconut oil is frequently used as a mouthwash to perform "oil pulling", a practice derived from traditional Ayurvedic medicine.

This involves swishing a small amount of vegetable oil around the mouth for several minutes before spitting it out. This technique is described as a means of reducing the oral bacterial load, improving oral hygiene and limiting gingival inflammation. With the cornflower hydrosol, coconut oil is today one of the most widely used natural extracts in this context, owing to its lauric acid content and its purported antimicrobial properties.

In this context, a clinical study assessed the antibacterial efficacy of coconut oil by comparing it with chlorhexidine, a standard oral antiseptic. The study included 50 girls aged 8 to 12, randomly allocated into two groups: one carrying out a daily coconut oil mouthwash and the other using chlorhexidine. Participants were instructed to rinse for 2 to 3 minutes each morning after brushing, over a 30-day period. The bacterium Streptococcus mutans, the principal agent involved in the formation of dental caries, was measured in saliva and dental plaque using a standardized test on days 1, 15 and 30. The results showed a statistically significant reduction in the number of S. mutans in both groups between the start of the study and day 30.

Day	S. mutans score in the “coconut oil” group	S. mutans score in the “chlorhexidine” group
0	2.20	1.72
1	1.76	1.52
15	1.24	1.00
30	0.84	0.68

Comparison of mean S. mutans scores in saliva between the "coconut oil" and "chlorhexidine" groups.

Source: BIJAPUR G. A. & al. Comparison of antibacterial efficacy of coconut oil and chlorhexidine on Streptococcus mutans: An in vivo study. Journal of International Society of Preventive & Community Dentistry (2016).

It is noteworthy that no statistically significant difference was observed between coconut oil and chlorhexidine in terms of antibacterial efficacy against this bacterium.

These results suggest that coconut oil could reduce the load of S. mutans in a manner comparable to chlorhexidine in this specific context. However, it is important to bear in mind that the study involved a small cohort, a specific population and a relatively brief duration, which warrants cautious interpretation of the findings.

Can coconut oil combat skin infections?

The antibacterial properties of coconut oil also generate interest in the field of dermatology. Several experimental investigations have examined its action against bacteria involved in skin infections. However, most of the available data stem from in vitro or animal models, necessitating cautious interpretation for its practical application.

A preliminary study investigated the activity of virgin coconut oil against Staphylococcus aureus, a bacterium commonly involved in skin infections. The researchers assessed the inhibitory effect of coconut oil on an isolated strain using a broth dilution assay. The results confirmed an inhibition of bacterial growth at a concentration equivalent to approximately 0.102% lauric acid. Analysis by electron microscopy revealed alterations in the bacterial cell wall, suggesting a direct destructive mechanism. Furthermore, coconut oil significantly enhanced the phagocytic activity of macrophages, indicating an additional immunomodulatory effect. These data suggest that virgin coconut oil combines a direct antibacterial action with potential support for the innate immune response.

Another study evaluated the activity of lauric acid against Cutibacterium acnes, the bacterium involved in acne inflammation. The results in vitro showed that lauric acid exhibited a minimum inhibitory concentration significantly lower than that of benzoyl peroxide, indicating a more pronounced antibacterial activity under these experimental conditions. C. acnes was found to be particularly susceptible to lauric acid compared with other skin bacteria also tested in the study.

Effets inhibiteurs de l’acide laurique sur la croissance de différentes bactéries. — Inhibitory effects of lauric acid on the growth of various bacteria.
Source: HUANG C. M. & al. Antimicrobial property of lauric acid against Propionibacterium acnes: Its therapeutic potential for inflammatory acne vulgaris. Journal of Investigative Dermatology (2009).

These results emphasise the antimicrobial potential of lauric acid and, by extension, virgin coconut oil.

However, it is important to recall that coconut oil has a rich, occlusive texture and a high comedogenic rating. In acne-prone individuals, its undiluted application to the face can favour pore blockage and counterbalance the theoretical benefits of its antibacterial activity. Thus, despite in vitro evidence of biological efficacy, we advise those with combination to oily, acne-prone skin to proceed with caution and avoid using the oil in its pure form.