Is platelet rich plasma therapy effective for shoulder injuries?

PRP: Many types and mixes/concentrations of prp. No uniform standardization yet. It can help.

Maybe....: The theory is that the body can't on its own get enough healing or growth factors to the area (tendon), but concentrated platelet injected there enhance the nutrients and growth factors to allow the body to heal it. While many doctors do this, the most robust scientific trials (randomized controlled trials) have been ambiguous as to if it really works. Insurance probably won't cover it (check...).