Much of this is a reflection of a deep anxiety about not achieving the “in” look of certain influential men — think of the physiques of athletes like Odell Beckham Jr., actors like Armie Hammer and models like David Gandy — men with highly defined necks, jaws, cheekbones, upper bodies and abs. The toxic aspiration on these sites isn’t representative of all men, but they give a telling, if limited, peek into the half-joking, self-hating ways in which men often talk to one another about their bodies. One of the most popular forums, Bodybuilding.com, has more than 137 million posts. In between workout and nutrition advice, it’s filled with some men calling not just others but also themselves “betas,” “low-T manlets” and a series of other put-downs.

While some of the evidence for this body image crisis can be atmospheric, hard to quantify, we know from the American Society for Aesthetic Plastic Surgery that the number of men undergoing cosmetic procedures between 1997 and 2015 increased by more than 325 percent. But for those with B.D.D., surgery is not a solution and can indeed make B.D.D. worse.

I’ve seen in my own patients, and in my research studies, how B.D.D. often causes social anxiety and avoidance, work or school difficulties, inability to do daily tasks or even leave the house. Many people with B.D.D. consider suicide. Some follow through. Fortunately, effective treatments (medications and cognitive-behavioral therapy) are available. And scientists are learning that B.D.D. involves aberrations in visual processing: Faces and objects can, in fact, literally look different to people with B.D.D. I’ve had many male patients with B.D.D. who were so obsessed and tortured that they could not hold a job, see friends or date. In reality these men were good-looking; other people did not see the defects they perceived.

Although suicidal thoughts are common among men with B.D.D., there are an untold number of men — young, older and in between — who do not have extreme symptoms but are beset by quiet desperation about their bodies nonetheless. They are the men who may just be feeling down about their body type and facial features if they aren’t “performing” well in today’s image-and-app-addled dating scene. We are all still reckoning with the virtually unlimited opportunities to check our appearance, manipulate it and compare it with others’.

To help mitigate this crisis, we can first acknowledge men’s body-image worries, which often go unrecognized. And among children, teenagers or adult friends, it’s important to remember that teasing, bullying or even negatively commenting on someone’s appearance in a joking way can be emotionally wounding and may contribute to the development of B.D.D.

It’s equally important for heterosexual men to remember that many media images are unrealistic and don’t necessarily portray what women find attractive: Men, for instance, tend to think that women prefer a far more muscular body than they actually do. (There is, indeed, even praise of the “dadbod” as cute in some circles.)

Perhaps more than anything, it’s crucial that we all reinforce the fact that masculinity (or femininity) is not defined by how you look — besides being untrue, it’s arbitrary.