The government recommends no more than 2-3 units for women and 3-4 for men every day or most days, and 48 alcohol-free hours after heavy drinking.
The Royal College of Physicians said the liver needed time to recover from more than just a small alcoholic drink.
It advises two to three alcohol-free days a week and 0-14 weekly units for women and 0-21 for men.
Sir Ian Gilmore, special adviser on alcohol and former president of the RCP, said: "In addition to quantity, safe alcohol limits must also take into account frequency.
"There is an increased risk of liver disease for those who drink daily or near-daily, compared with those who drink periodically or intermittently.
"We recommend a safe alcohol consumption limit of between 0 and 21 units a week for men and 0 and 14 units a week for women provided the total amount is not drunk in one or two bouts, and that there are two to three alcohol-free days a week.
"At these levels, most individuals are unlikely to come to harm."
In an interview with Radio 4's Today show, Sir Ian added: "If someone drinks one drink a day, one small drink every day of their life, they're most unlikely to run into harm. But if you are going out and having a lot to drink then you should perhaps rest your body."
The latest NHS figures showed that alcohol-related hospital admissions reached record levels last year.
More than one million people were admitted in 2009-10, compared with 945,500 in 2008-09 and 510,800 in 2002-03. Nearly two in three of those cases were men.http://www.bbc.co.uk/news/health-15415713