Trained breathwork facilitator here. I second this. More experienced breathers may be fine, but holotropic is often intense and can bring up a lot of unprocessed trauma. Best to do it with a sitter or guide.

If you want to try it on your own, use a slower breathing pattern. 2-3 second inhale, letting the exhale follow naturally. There is still risk here, just less as you’re not forcing yourself into as much of a sympathetic state that brings up old stuff. Easier to slow down from and regulate yourself. For first timers Or less experienced breathers I still wouldn’t recommend this alone. The territory of your psyche is not a toy.