Why Is It So Hard for Men to Make Close Friends?

One simple way to practice being emotionally unguarded is to “tell your friends how you feel about them,” Mr. Fager said. “It’s just so important for your friends to know that you value the relationship — that you admire the person or you respect the person or you love the person.” He acknowledged that it might feel quite uncomfortable to call someone out of the blue and tell them that you love them; instead, consider sharing your appreciation after spending time together or on the heels of an emotional exchange.

“If you’ve already been there for your friend in some way, on the tail end of that, there is often an opening for some sort of acknowledgment of how much you value the relationship,” he said. If you feel discomfort, that is something to “be aware of and question where it is coming from,” Mr. Fager added.

Another strategy is to join a structured peer-support group or partake in group therapy, Dr. Rabinowitz said. Since 1986, he has run a weekly men’s group in Redlands, Calif., that provides a set time for men to, as he put it, “take the risk and say, ‘Hey, I have a lot of stuff going on, and I don’t have anyone to process that with.’” One benefit of joining a support group is that you are likely to encounter men who are up for the challenge of creating emotional connections with other men.

Connor Beaton, 39, founded ManTalks after he realized how learning to be vulnerable had transformed his own friendships. The company helps men connect with each other through in-person workshops and online courses.

Several years ago, as he struggled with substance abuse, Mr. Beaton opened up to a friend he’d known for years — a man he’d lived with and traveled with extensively. The friend surprised him by, in turn, sharing that he had recently grappled with suicidal ideation.

“It really hit me at that moment that I simultaneously knew everything about this man right down to what kind of Scotch he liked to drink, and I had no idea he was struggling so intensely,” Mr. Beaton said.

But practicing vulnerability does not require attending a workshop or having deep, unfiltered conversations about your inner life. You can keep it simple, said Marisa Franco, a psychologist who studies friendship and the author of “Platonic: How the Science of Attachment Can Help You Make — and Keep — Friends.”