Super-spreaders
Socks can also play a key role in spreading fungal infections like Tinea pedis (better known as athlete’s foot), a highly contagious condition that primarily affects the toes but can spread to the heels, hands, or even the groin. The infection is caused by dermatophyte fungi, which love warm, damp environments – exactly the kind you find in sweaty socks and tight shoes.
To prevent this, experts recommend avoiding walking barefoot in shared spaces like gyms and pools, not sharing socks, towels, or shoes, and practising good foot hygiene, which includes washing and drying thoroughly between the toes. Topical antifungal treatments are usually effective, but prevention is key.
It’s also important to note that socks can retain fungal spores even after washing. So if you’ve had athlete’s foot, wearing the same pair again – even if it looks clean – could trigger reinfection.
The safest approach is to wear fresh socks daily and allow your shoes to dry out completely between wears. Choose breathable fabrics and avoid footwear that traps heat or causes excessive sweating.
How to wash your socks properly
Most laundry advice focuses on preserving fabric, colour and shape – but when it comes to socks, hygiene matters more. Studies show that washing at typical domestic temperatures (30–40°C) may not be sufficient to kill bacteria and fungi. In fact, under-cleaned socks can act as infection vectors, especially in households with vulnerable people.
To properly sanitise your socks:
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Turn them inside out before washing to expose the inner surface where most microbes accumulate
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Use an enzyme-based detergent, which helps break down sweat and skin debris
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Wash at 60°C when possible, as the higher temperature helps detach and kill microbes
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Steam iron your socks if you need to wash at lower temperatures – heat from ironing can destroy residual spores.
Cotton socks tend to tolerate higher temperatures better than synthetic blends, making them a better option for those prone to fungal infections. Drying socks in direct sunlight can also help: UV light has known antimicrobial effects.
The forensic power of sock microbiomes
Your socks might say more about you than you realise. In a US murder investigation, forensic scientists used soil bacteria found on a suspect’s socks to link them to the burial site of a victim.
The microbial profile of the socks closely matched that of the crime scene – suggesting the socks had picked up and preserved location-specific soil microbes. This emerging field of forensic microbiology shows how microbial signatures can offer valuable clues in legal contexts.
It’s a reminder that the ecosystems we carry on our bodies – and in our clothing – are not only complex and revealing but also surprisingly durable. Whether it’s helping to solve crimes or fuelling a fungal outbreak, your socks are far more biologically active than they appear.
So next time you peel off a sweaty pair at the end of the day, spare a thought for the microscopic universe you’ve been walking around in. And maybe, just maybe, opt for that 60-degree wash.
Primrose Freestone, Senior Lecturer in Clinical Microbiology, University of Leicester
This article is republished from The Conversation under a Creative Commons license. Read the original article.