The Pornstar Martini has been crowned the most hangover-inducing cocktail, according to a new study that ranked classic serves.

The study from online retailer On Buy sought to rank classic cocktails and create a Cocktail Hangover Index.

A survey of 2,892 people tasked participants with scoring each of the 15 cocktails featured on qualities such as resulting headaches, feelings of sickness, or the amount of time wasted in bed the following day.

On Buy asked drinkers to rate 15 classic cocktails including the Sex on the Beach, Cosmopolitan, Bloody Mary, Pornstar Martini, Negroni, Tom Collins, Singapore Sling, Margarita, Tequila Sunrise, Whiskey Sour, Old Fashioned, Piña Colada, Strawberry Daiquiri, Mojito and Long Island Iced Tea.

After rating each drink, the survey found that the Pornstar Martini was the most hangover-inducing, while respondents rating the Mojito as the least.

Click through our gallery to see which cocktails made up the top five most hangover-inducing serves.