There were several people working on this but their work was defunded and buried. The problem with the work wasn't the regrowth it was that that the research showed the power of sun light and circadian rhythms. Such rhythms when harnessed properly destroys chronic disease and removes the need for the corrupt centralized health system. The research also showed the dangers of blue light which our tech overlords have invested in and thus anything that goes against the positive public perception of blue light tech is suppressed.
I have heard some fascinating but incredible claims about this stuff, that I haven't researched yet. Supposedly, supplying a wound with energy, as in literally hooking up powered electrodes to the area, has been shown to enable actual regeneration of flesh. Also, scar tissue prevents healthy regrowth of the body, and if you can keep a wound healthy and sustainable while preventing scar tissue formation, the effected area can actually regrow healthfully.
Jump on youtube and look up Dr. Jack Kruse interviews. I can't remember which one I heard it in because I've probably listened to 15-20 in the last few months. Did you have a particular question? Are you more concerned about the regrowth or the sun light hypothesis?
https://saidit.net/s/debatealtright/comments/eomq/sunlight_is_more_important_than_we_thought_jews/
I will look for the segment where Jack talked about a human limb growth researcher in the military and if I find it I'll send it.
I think Jack was talking about this 1/4 billion dollar investment 20 years ago:
https://www.bu.edu/sjmag/scimag2008/Story%20pages/DARPA.html#:~:text=In%20August%2C%20the%20military%20launched,animals%20to%20regenerate%20lost%20tissue.
It was one particular researcher on that team that discovered the light connection to bone growth.