The average UK adult drank 10.2 alcoholic drinks per week last year, the lowest level since records began in 1990.
This marks a significant drop from around 14 drinks per week at its peak 20 years ago.
The downturn appears to be driven by moderation rather than widespread abstinence.
IWSR points to a combination of rising living costs, increased health awareness, an ageing population and a shift towards premiumisation as key factors behind the trend.
“The population is ageing and older consumers physiologically can’t drink as much,” said IWSR president Marten Lodewijks.
“There are also elements of health consciousness, and with the cost of living rising, people simply can’t afford to drink out as much.”
Premiumisation is also playing a role, with consumers opting for higher-priced drinks while reducing overall volumes, helping the sector maintain revenues despite lower sales.
However, separate research from charity Drinkaware suggests heavy drinking remains common on special occasions, with 57% of UK adults expected to binge drink on Christmas Day.
The proportion rises to around three quarters among those aged 18 to 34.