How short should fue donor hair be?

Hair transplant surgeon needs to be able to see the angle and curvature of your hair in order to properly aim and harvest them.  I usually trim it to 1mm length but I can go as long as 3mm too if I have to.

We generally do this with either a strip surgery with long hair, or a long haired FUE. To do this right, you have to align the hair angle in the proper direction so that the hair grows flush against the skin. A very short hair from an FUE with a 1 mm shaved hair graft, would not show the hair direction.  That means that the ideal direction would not be certain., so I prefer a very small strip surgery. See the web reference below for a more extensive discussion which I wrote for one of my other websites.