From a medical perspective, it is difficult to determine whether 75 Hard is beneficial.

NHS GP Sam Whiteman points out that, because “it has not been studied” in a clinical setting, it cannot claim to change your life in any way.

He also says that it would need to be compared to a more basic regime, to see if that could achieve the same results.

“If it’s a way for people to get out and be active then I am all for it, but if it’s a question of whether this is better than going to the gym three times a week or going for a run once a week and eating healthily, then I am not sure,” he adds.

Hitting certain criteria isn’t the intention of 75 Hard’s founder, Mr Frisella. He doesn’t set any rules that involve losing a certain amount of weight, for example.

While the challenge encourages people to take progress pictures each day, much of the TikTok content around it focuses on how the person feels at the end rather than how they look, helping to avoid unhealthy fixations with appearance.

Dr Whiteman recommends visiting the NHS Live Well website, external, which has tips on what constitutes a healthy weight, diet and exercise regime, along with mental health and sleep advice.