University College London (UCL) and the BBC recorded noise on the tube for one week and found that ambient sound on some lines approaches the level of a chainsaw.
On average the Victoria Line was the noisiest while parts of the Northern and Jubilee lines are so loud they would require hearing protection if they were workplaces.
Although Transport for London said the noise was ‘highly unlikely’ to cause long term damage to hearing, experts at UCL said it could be harmful for people with lengthy daily commutes.
Dr Joe Sollini, of UCL's Ear Institute said it was concerning that many journeys were louder than 85 decibels - the level that requires hearing protection in a workplace.
"Hearing loss accumulates over our lifetime," he said.
"If someone was on a noisy Tube line every day for long journeys, it is perfectly possible this could increase the risk of hearing loss and potentially tinnitus."
The loudest recorded Underground journey through central London was between Liverpool Street and Bethnal Green, which peaked at 109 decibels - louder than a helicopter taking off nearby
London Underground's Nigel Holness said noise levels were monitored frequently on the network to make sure passengers and staff were safe, but said the company was investigating how to make further reductions.
He told the BBC: "While customers travelling on our network can experience noise, higher volumes tend to be for short periods of time and Health & Safety Executive guidance on noise suggests it is highly unlikely to cause any long-term damage to customers' hearing."
However Peter Rogers, from the Institute of Acoustics, urged TfL to introduce "quieter carriages".
"We can do it on trains, so we should do it on London Underground carriages, creating a more pleasant, quieter experience," he said.
The full investigation can be seen on Inside Out London on Monday 29 January at 19:30 GMT on BBC One and iPlayer.