18 months FUE post-op, still have patches of stubble - failed grafts?

At 18 months post-FUE, your hair transplant result should be fully mature — by this time, all surviving grafts have already grown.
If there are patches of stubble that never grow longer, it is most likely that these represent failed or miniaturized grafts, meaning the follicles were either:

Partially damaged during extraction or implantation,

Did not establish sufficient blood supply, or

Underwent chronic inflammation or fibrosis that prevents new growth.

Because they are not falling out easily, it means some root structure remains, but the follicle is non-functional (similar to a scarred or dormant follicle).

This answer has been approved by Dr. Arslan Musbeh.

Dear Funny684081

Thanks for your query. Viewing your pictures would be more helpful in forming an opinion about your results from your story. First, you could consider some PRP treatments. If that doesn't provide the desired improvement, you may proceed with the second session of FUE hair transfer. To achieve a smooth and uniform hairline, we recommend consulting with your operating doctor. They can provide a more precise answer based on your specific situation.

Regards
TAS TEAM

18 months should be sufficient time to see the final results of a hair transplant procedure. Without a photo its difficult to say what the "stubble" is that you're seeing. When a transplanted follicle fails to grow a hair, you wouldn't necessarily see anything on the surface (especially after 18 months), it would just be a bare area. Again, photos might be helpful here, but I would recommend following up with your hair transplant surgeon to share your concerns.

Most of the transplanted hair should grow by the 12-18th months. So if you have reached the 18th month, then do not expect anymore growth or improvement. You may consider taking medication like Propecia or apply Rogaine or consider another hair transplant surgery to fill in the bald area.