Mayo Hack

Hellman's UK

Brand Marketing

The hack that finally made McDonald’s UK serve mayonnaise.

The Challenge

Hellmann’s is the number one mayonnaise brand in the UK and has always championed the cause of mayo lovers. As market leaders, the brand goes the extra mile to ensure that mayo lovers can enjoy their favourite condiment wherever and whenever they desire. 

Yet while mayonnaise is the most popular condiment in the UK, the major fries seller in the country, McDonald’s, did not offer mayo as a dip. Despite mayo's immense popularity, a McDonald’s spokesperson publicly stated that "there's not enough demand for it." 

To support the rights of mayo lovers, we decided to take a stand against this injustice, and set out to right this wrong.

The Strategy

When McDonald's failed to listen to the demands of their customers, we knew we had to take matters into our own hands. While the fast-food giant didn’t serve mayo as a dip, they did serve many items, including The Mayo Chicken burger, which featured the creamy condiment. 

To give customers the opportunity to express their love for mayo, we launched a helpful hack for the Mayo Chicken, sharing that you can customise the offering on the chain’s ordering system, removing ingredients until there's only one left — mayo.

By leveraging one of McDonald’s flagship burgers and asking people to turn it into an order of mayonnaise, we could turn every McDonald's order screen in the UK into a vessel for our campaign and the message that fries with mayo is the happiest meal of all.

The Execution

With this, we launched Mayo Hack — a hack that gave the UK their well-deserved mayo with fries at McDonald’s. We launched with an integrated campaign and encouraged people to customise their Mayo Chicken burger by de-selecting the chicken, lettuce and bun, leaving just the mayo. 

We finally made McDonald’s serve mayo, and people who posted a photo of their hack were given the cost of the burger by Hellmann’s. To support further, we promoted the hack on DOOH screens outside of McDonald’s restaurants, in print ads in regional newspapers, and on Hellmann’s own social channels. 

We also reached out to the hundreds of people on social media who previously had asked McDonald’s to add mayo as a dip, telling them we had come up with a hack to serve them mayo. To maximise social engagement, we also collaborated with five foodie influencers who created their own instruction videos.

The Outcome

The Mayo McHack campaign emerged as one of Hellmann’s UK’s most successful social initiatives, achieving a 842% increase in social impressions and a 320% rise in engagement. 

The campaign led to a 46% boost in brand consideration and a 9-point increase in purchase intent. 

Additionally, 72% of respondents agreed that McDonald’s should serve Hellmann’s mayo.


increase in social impressions


increase in engagement


increase in purchase intent