Tendinopathy in upper limb tendons, driven by overuse or understimulation, is very frequent in the general population. Because of the absence of effective treatments, biological approaches are currently being investigated. Platelet-rich plasma (PRP) is injected locally for the conservative management of epicondylar and rotator cuff tendinopathy, or as a biological enhancer in arthroscopic repair of rotator cuff tears. In epicondylar tendinopathy, we have identified 15 randomized clinical studies comparing the efficacy of PRP with other injectable treatments. PRP has been compared with corticosteroids in 8 randomized trials, showing better results in long-term clinical outcomes; PRP was compared with peripheral blood in 3 studies, showing similar outcomes but fewer adverse effects; 2 studies showed superiority of PRP versus anesthetics using a peppering technique. In 1 study, PRP did not show any clinical efficacy when compared with dry needling, and no efficacy in 2 studies compared with saline injections. Four randomized controlled studies have examined PRP injections in chronic shoulder tendinopathy, but the evidence is inconclusive. PRP as an enhancer of arthroscopic management is questionable but data are evolving as more subgroup analyses become available. PRP therapies have only partially fulfilled therapeutic expectative, and new approaches are necessary.