The popular protocol nowadays would be BPC-157 and/or TB-500. BPC-157 is typically dosed at 500mcg - 1mg per day, which can be dosed in a single injection every 24 hours or two injections 8-12 hours apart (intramuscular or subcutaneous, with the injection site being largely irrelevant). TB-500 is typically dosed at 5mg - 10mg per week (longer half-life than BPC), which can be dosed every 3.5 days (intramuscular or subcutaneous).
The dosage protocols of both of these peptides can vary pretty widely depending on the individual, but these are the most common dosages I've seen. Theoretically, if cost is not an issue, you could increase the doses substantially higher than the dosages I suggested. The length of the cycle would be determined by your symptoms. Ideally, you would run your cycle until your symptoms are gone or negligible. A lot of anecdotes I've come across seem to fall in the 30 - 60 day range. I've personally only used BPC-157, and my protocol was 1mg/day for ~40 days to help alleviate left triceps tendonitis. It took a couple weeks for me to notice relief, and I also trained exclusively in the 15-20 rep range for all upper body pushing exercises during this period to reduce the absolute load on the tendon (I would suggest you do the same for all movements that aggravate your affected tendon, train them in the 15-30 rep range). At the end of my cycle, my left triceps tendon pain was reduced from a 7-8/10 pain level to a 3/10 pain level (I probably could have extended the cycle for more benefits, but honestly once I ran out of BPC I was just too lazy to order more and didn't feel like spending the money, lol).
Now, I don't have personal experience with this, but allegedly HGH can work wonders for soft tissue injuries, and is considered to be the true gold standard for healing injuries of that variety. I'm not going to recommend any specific protocol, since I'm not confident enough in my knowledge of HGH to give specific advice, but it may be something you want to look into and consider (and perhaps a more knowledgeable user here can chime in).
Best of luck with the healing and recovery, tendonitis can be a real pain in the ass. Wish you the best.
