This has been asked and answered many times here. I understand the confusion in the patient community but am less sympathetic when a medical professional is involved.
The Afrezza dose size is not equivalent to liquid glucose. It has a much faster onset and peak and a much shorter duration than a rapid acting analog insulin. I’ve used Afrezza for over two years now, mostly for corrections. It is very forgiving with regard to its labeled dose and rarely drives me hypo. The best thing any person with diabetes can do is to try it themselves with safety measures in place and see what they think.
Unfortunately, doctors are the gatekeepers for this and other medications. It seems many of them judged Afreeza too quickly on the first layer of analysis they heard.
For me, a 4-unit dose of Afrezza acts more like a two-unit dose of liquid insulin with its tail cut off at about 2.5 hours. It’s great for night-time corrections and the ability to confidently go back to sleep without a nagging fear of a hypo while I sleep. It’s amazing that way. If I could no longer get Afrezza, I would sorely miss it.