Study warns household insecticide may damage muscles, disrupt glucose metabolism

A new study has raised concerns about the potential health risks of transfluthrin, a widely used household insecticide, after researchers found that exposure damaged muscle cells and disrupted glucose metabolism in laboratory experiments.

The study, conducted by researchers at the Skeletal Muscle Lab, Institute of Integrated and Honors Studies, Kurukshetra University, India, and published in Toxicology, suggests that the synthetic pyrethroid may affect the body beyond its established effects on the nervous system.

Transfluthrin is commonly used in products designed to control mosquitoes, flies, moths and cockroaches, including aerosol sprays, mosquito coils and vapour-based insect repellents.

According to the researchers, their findings indicate that the chemical can trigger oxidative stress, impair mitochondrial function and cause muscle cells to shrink, raising questions about the potential consequences of repeated household exposure.

The researchers described their findings as evidence that transfluthrin can directly interfere with skeletal muscle cell metabolism, highlighting a possible health risk that warrants further investigation.

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In the laboratory experiment, researchers exposed muscle cells known as myotubes to varying concentrations of transfluthrin.

Myotubes are elongated, multinucleated structures involved in the development and functioning of skeletal muscles.

The researchers observed changes in the cells’ shape and a dose-dependent increase in glucose consumption and uptake. However, the increased glucose utilisation did not indicate improved muscle performance.

Instead, the findings suggested that the exposed cells broke down more glucose, producing increased levels of lactate, which can adversely affect mitochondrial function.

Mitochondria are responsible for generating much of the energy cells require to function. The study found that transfluthrin disrupted the electrical potential across mitochondrial membranes, potentially compromising energy production.

The exposed muscle cells also became shorter and narrower, changes the researchers associated with muscle atrophy.

Additionally, the experiment recorded increased levels of reactive oxygen species and reduced glutathione, an antioxidant that helps protect cells against oxidative damage.

The researchers also identified disruptions in the cells’ protein maintenance processes, further suggesting deterioration in muscle cell health.

The findings add to existing research examining the potential health effects of synthetic pyrethroids, a class of insecticides introduced in the 1960s and widely used in household pest-control products.

Although these chemicals were developed as alternatives to older insecticides, concerns have emerged about their possible effects on human health and the environment.

An earlier epidemiological study using data from the United States National Health and Nutrition Examination Survey associated pyrethroid exposure with reduced handgrip strength and skeletal muscle mass.

Other research has linked transfluthrin exposure to asthma susceptibility in children, while a 2025 Chinese study identified associations between pyrethroid exposure and respiratory conditions, including asthma, chronic obstructive pulmonary disease and pulmonary fibrosis.

Previous laboratory studies have also investigated possible reproductive effects associated with transfluthrin exposure.

The latest findings are particularly significant because glucose metabolism is essential to muscle function and overall health. Disruptions in cellular energy production may contribute to physical weakness, while metabolic disorders such as diabetes and obesity are themselves associated with muscle deterioration.

Despite the findings, the researchers cautioned that their study was conducted in vitro, meaning the experiments involved cells outside a living organism.

Further research involving laboratory animals and, ultimately, human studies would be necessary to establish whether comparable effects occur under real-world exposure conditions.

The study also raises questions about whether existing pesticide safety assessments adequately account for potential effects on muscle metabolism, rather than focusing primarily on established neurological mechanisms.

Transfluthrin exposure can occur through inhalation, particularly when products release the chemical into indoor or outdoor air.

Researchers say further investigation is needed as transfluthrin-based products continue to be developed for mosquito control in homes, recreational spaces and other environments.

The findings do not establish that normal household use causes muscle damage in humans. However, they provide additional evidence supporting further assessment of the chemical’s potential biological effects.

Consumers seeking to minimise exposure can follow product safety instructions, ensure appropriate ventilation and avoid unnecessary or excessive use of insecticides.

The researchers’ findings underscore the need for additional studies to determine the potential long-term health implications of repeated exposure to transfluthrin and other synthetic pyrethroids.