In a survey of more than 3,000 men, 39 per cent said they had had a disappointing reaction when they shared things about their mental health in the past, charity Time To Change found.
Only a quarter would openly tell their male friends if they were struggling with their mental health.
Being able to listen was more important than giving advice, the charity said.
Time to Change added that phrases like “man up” were never helpful, as 42 per cent of men say phrases like that are conversation blockers, and it advised men to know when to end the banter.
Dominic Arnall, head of programme management said: "Simply providing men with the confidence to support their friends has the power to change lives, and it doesn’t need to be difficult or scary.
"We all know that the usual and expected response to ‘How are you?’ is ‘Fine thanks’. Ask again if you’re worried about a friend – a simple ‘Are you sure you’re ok?’ can be the signal they need to open up."