The study, published in the latest version of the Journal of the American Medical Association, adds weight to the long-held belief that GPs' willingness to prescribe antibiotics increased infections' resistance to drugs.
Researchers studied 166 patients suffering sinus infection and gave them all a week's supply of over-the-counter medication.
Bad news for sufferers: A study has found that a course of antibiotics does little to alleviate the painful symptoms of sinus infections
Half of the patients were also given a 10-day course of the antibiotic amoxicillin, while the other half were given a placebo.
The researchers checked whether symptoms - facial pain, cough, runny or blocked nose - showed any significant improvement between the two groups.
Patients were checked at predetermined intervals over four weeks.
Over-prescription: The study backs up the long-held belief that GPs are reducing the effectiveness of antibiotics by prescribing them for all kinds of ailments
The results of the study show that - a week into the study - there was a marginal change for the better in the antibiotic group.
But researchers ruled that there was little noticeable relief in symptoms - certainly not enough for antibiotics to be ruled any more effective than over-the-counter medicine.
It is an important result, as the research leaders say one in five antibiotic prescriptions in the U.S. are for sinus infections.
Sinus infection: Inflammation of the airways can lead to headache, facial pain, a cough and blocked nose
Study author Dr Jane Garbutt, a research associate professor of medicine and pediatrics at Washington University School of Medicine in St. Louis, told WebMD: 'I think the data are something like 90 per cent of people that go to a doctor's office and receive this diagnosis will be given an antibiotic prescription.'
'I think that we should try and significantly reduce that percentage.'.
But doctors believe it would be too hasty to write off antibiotics, pointing to the fact that Dr Garbutt's study only focussed on amoxicillin, to which infections have a high resistance.
New York ear, nose and throat specialist Dr Linda Dahl said antibiotics such as Augmentin, Levaquin, and Biaxin could still be effective.
Her advice to patients suffering from sinus infection was to stick it out with over-the-counter decongestants for a week or two, adding: 'If you've been sick for two weeks and have been taking decongestants, it's probably not going to get better on its own.'