Bakersfield, California, is a large city about 100 miles north of Los Angeles. Founded on recovered swampland by Colonel Thomas Baker, it is today famed for oil, gas and agriculture, as well as for being the country music capital of America's west coast.

But Bakersfield is also where, in 1966, a student nurse named Lupe Hernandez first dreamed up the idea of hand sanitiser. The story goes that Hernandez realised alcohol delivered through a gel could clean hands in a situation where there was no access to soap and warm water. Recognising the commercial potential of her idea, she duly called an inventions hotline she had heard about on television and set about registering the patent.

Forty-six years ago, even Hernandez could not have predicted the explosion in popularity that hand sanitiser has experienced in recent times. In the US alone, the growth of the market is astounding: valued at $28m (£17m) in 2002, it had swollen to $80m (£50m) by 2006, and is predicted to be worth some $402m (£250m) by 2015.

In matters of hygiene, the UK tends to follow where the US has led – and in the case of hand sanitiser, that certainly appears to be the case. Since I operate on the theory that a little bit of dirt does us good, I don't carry hand sanitiser – but I recognise that I am increasingly in a minority. For the past couple of years, bottles of antibacterial gel have become an increasingly common sight in Britain, and most particularly in London. It has become a handbag must-have, a public transport companion, a desk-mate in the office and seemingly invaluable for mothers wiping down sticky toddlers.

I see people exiting the tube, cleansing themselves of whatever nasties they may have picked up from the escalator handrails; I see them in their offices, slicking their hands before they touch their computer keyboards; I see them on their lunchbreaks, sitting down at cafe tables and indulging in a quick preprandial hand-gelling. They are women mostly, crisp and well-dressed, their hand sanitiser now just another part of their well-run hygiene routine. And even those who have yet to introduce antibacterial gel into their lives with anything approaching real rigour still seem to carry it – tucking it into their handbags like some kind of posy to ward off the plague.

Since early 2010, even WH Smiths has stocked small bottles of hand sanitiser, perched by the till in its airport, railway and service station stores. Superdrug reports a 12% increase in sales of hand sanitiser compared with this time last year. And with the summer approaching – and along with it, holidays, festivals, picnic and trips to the beach – sales are likely to climb further and faster. Soap manufacturer Gojo, the maker of the US best-selling hand sanitiser brand Purell, calculate that the professional market in the UK is worth around £10m. Although it does not currently sell hand gel for the UK consumer market, its research suggests that it is worth the same.

Once, hand sanitiser was the stuff of institutions: hospitals and care homes, for use by the armed forces and, in the US, at large public places such as restaurants and supermarkets, for those concerned by the germ-laden prospect of cutlery and shopping trolley handles. Its transition to essential personal accessory began in the wake of the H1N1 outbreak of 2009, when sales of antibacterial gels and wipes soared in the US: market research company Nielsen reported that, in the 24 weeks leading up to 3 October that year, the sector experienced a sales increase of 71% to $118.4m (£73m), compared with $69.4m (£44m) the previous year. The Walt Disney company installed 60 bulk sanitiser dispensers in the hotel lobbies, park entrances and character meet-and-greet areas of its Florida theme parks. It seemed as if wherever you went and whatever you did, it should be preceded by a precautionary squirt of sanitiser.

Gojo released Purell, the first commercial antibacterial hand gel, in 1988. In the years since, a variety of public health scares – from Sars and avian flu to swine flu – spurred consumer demand for such products. Scientific research, meanwhile, has delivered a string of ever-horrifying statistics to encourage our antibacterial urges, such as the fact that the spread of diarrhoea and gastrointestinal illnesses can be almost halved by practising effective hand hygiene. The British Medical Journal last month reported that a four-year study linked hospitals' increased use of soap and alcohol hand rub with a drop in the rate of superbug infections.

But the appeal of hand sanitiser has not been solely about hygiene; as sales grew, it swiftly became something akin to a fashion accessory as much as a necessity – a way of advertising your cleanliness. A report in the Los Angeles Times during the period of the H1N1 outbreak noted that the growth in hand gels had also spawned a demand in personalised dispensers: "Consumers can go online and order them in fur-trimmed pump bottles or in containers printed with their company names," it observed. "Pier 1 Imports is selling holiday-themed sanitisers with scents such as cinnamon and cilantro, packaged as nicely as perfumes."

The popularity of hygiene products often spreads this way. "Disgust sensitivity varies in the population, in the same way that height varies – most people are somewhere in the middle, but you find extremes at either end of the spectrum," says Dr Val Curtis, director of the Hygiene Centre at the London School of Hygiene and Tropical Medicine. "It's a particular group of people who use hand sanitiser at first, people who are particularly squeamish about dirt and germs. The marketing challenge is then to spread the usage outside of that group."

An outbreak of disease will encourage use outside of that initial squeamish group, says Curtis: "When you have a sense of high contamination in a population it moves people into the next category – it's no coincidence that during the swine flu epidemic there was an increase in clinical concentration of OCD."

But Curtis warns against a marketing campaign that increases our sense of contamination. "It's not good for mental health," she cautions. Instead, the most effective way to get people to practise good hygiene or to use a specific product is to increase the sense of disgust. "The most powerful marketing tactic is the power of social norm," Curtis explains. "In studies we conducted in the bathrooms of service stations, we found that the best message to convince people to wash their hands was moral – we put up signs saying: 'Is the person next to you washing their hands?'"

Thanks to the heightened fear of contamination experienced during recent flu epidemics, there is now a value judgment attached to carrying and using an antibacterial gel. "Purity is associated with goodness," says Curtis. "Cleanliness and godliness do go together. People start to feel ashamed of not having clean hands, because the message is that you are not protecting others from your germs."

But hand sanitiser's appeal does not stop there. It also, as some teenagers have realised, offers alternative uses: earlier this year, it was reported that teens were drinking hand sanitiser as a way of getting intoxicated. After all, ethanol-based gels can contain more than 60% ethanol, meaning they are 120 proof. Tequila, by comparison, is around 70-80 proof, and a great deal harder to purchase if you are below the legal drinking age. A CNN survey of poison control centres across the US found that last year there were 622 calls regarding teens and hand sanitiser (77% were concerned with oral consumption). In the first quarter of this year, there had already been 203 calls.

Aside from their moral, aesthetic, convenient and intoxicating appeal, however, the benefits offered by hand sanitisers may not be quite the magical cure-all we think them to be.

Dr Ron Cutler, senior lecturer at Queen Mary University of London and an expert in infection control, has noted hand sanitiser's growing popularity with interest. "You see a lot of people, especially young ladies, tend to use it on the tube and on the train, and I see students here using gels and wipes," he says. "What has happened with society is that we're seeing multi-drug-resistant organisms that seem to be more common than they ever were before. And it's been shown several times that when these superbugs get out, they do tend to grow like never before. People are concerned about that, so you get an increase in the number of people buying hygiene products."

In such a climate, it is both enticing and reassuring to see your hand sanitiser of choice emblazoned with proof of its efficacy, each promising to obliterate an impressively high percentage of germs. However, Cutler tempers such enthusiasm: "These sanitisers state that they kill 99.9% of germs, but the difficulty is that the data was done on inanimate surfaces, and they don't replicate what happens on the human hand," he says. And the human hand is different because "you have flora on your hand that lives there and interacts with other bugs on your hand". And these percentages may not actually be so impressive. "My take, as a bacteriologist, is that 99.9% is nothing when you consider that organisms live in communities of 10 hundred billion; that 0.1% can mean a lot of bacteria!" Cutler says.

And a little bewilderingly, some studies suggest that hand sanitiser may even be detrimental to our health. Hand-sanitising gels work by removing the top layer of oil from our hands, taking with it some of the good bacteria on our skin; they can also dry the skin, so many manufacturers have begun to add moisturising ingredients to counteract the effect of the alcohol.

Questions have also been raised about triclosan, an ingredient in many hand sanitisers, as well as in some liquid soaps, shaving gels and dishwashing liquids. The Food and Drug Administration in the US has said that research shows "valid concerns" about triclosan, including whether it can disrupt the body's endocrine system and help create bacteria that are resistant to antibiotics. Furthermore, Cutler adds that hand gels can be affected by the type of grubbiness they encounter. "Put simply, dirt, particularly some faecal proteins, can sometimes inactivate sanitisers," he explains.

And on top of all this, aren't hand sanitisers just a little bit wasteful? All that plastic, all that manufacturing energy, when in many cases we could just use soap and water to clean our hands?

In fact, numerous studies have shown that sanitiser is no more effective than soap and water in stopping the spread of colds, flu and other respiratory diseases. "People think they're more effective than water because you don't see adverts for soap and water saying the percentage of germs they kill," says Cutler. "But the FDA doesn't recommend hand sanitiser in place of soap and water."

Curtis agrees. "Hand gel is desirable, but it's not absolutely essential," she says. In many ways, it might be compared to bottled water – preferable, perhaps, in a world of consumer choice and convenience, but in a country where infection and disease is small compared with developing nations, far from vital. "We live in a world where we have much fewer risks and so we start to worry about smaller risks," Curtis explains. "But we can just use normal soap and water from the tap."

This is not to downplay the importance of clean hands. Curtis and Cutler are involved with Global Handwashing Day, an initiative that seeks to raise awareness about the importance of washing hands in reducing the spread of infection. "There is nothing wrong with washing your hands," Cutler insists. "I'd be the first to say that. And in fighting epidemics, hygiene and hand-hygiene is a solution. But I don't think hand sanitisers are an alternative to washing hands."