Aim of the present pilot study was to verify, for the first time ever, the effects of collagen injections in patients with chronic supraspinatus tendinopathy. Eighteen patients with chronic supraspinatus tendinopathy were treated with a series of 4 type I porcine collagen ultrasound-guided injections, at weekly intervals. The effects were verified at 2-week, 1-month and 3-month follow-up by means of shoulder scoring systems and sonography. A very strong evidence (p<0.001) of a statistically significant main effect amongst the multiple clinical observation was found. Ultrasound imaging highlighted improvement in the structural integrity of the tendon. Compared to other injection therapies, collagen injections proved to be at least equally effective, faster acting and safer.