Here is a case with Nandrolone showing positive effects on tendons, I still have yet to see one study showing boldenone and it's effects on colagen synthesis.
Triantafillopoulos IK, Banes AJ, Bowman KF Jr, Maloney M, Garrett WE Jr, Karas SG. Nandrolone decanoate and load increase remodeling and strength in human supraspinatus bioartificial tendons. Am J Sports Med. 2004;32(4):934-43.
ABSTRACT
BACKGROUND: To date, no studies document the effect of anabolic steroids on rotator cuff tendons. STUDY DESIGN: Controlled laboratory study. HYPOTHESIS: Anabolic steroids enhance remodeling and improve the biomechanical properties of bioartificially engineered human supraspinatus tendons. METHODS: Bioartificial tendons were treated with either nandrolone decanoate (nonload, steroid, n = 18), loading (load, nonsteroid, n = 18), or both (load, steroid, n = 18). A control group received no treatment (nonload, nonsteroid [NLNS], n = 18). Bioartificial tendons' remodeling was assessed by daily scanning, cytoskeletal organization by staining, matrix metalloproteinase-3 levels by ELISA assay, and biomechanical properties by load-to-failure testing. RESULTS: The load, steroid group showed the greatest remodeling and the best organized actin cytoskeleton. Matrix metallo-proteinase-3 levels in the load, steroid group were greater than those of the nonload, nonsteroid group (P <.05). Ultimate stress and ultimate strain in the load, steroid group were greater than those of the nonload, nonsteroid and nonload, steroid groups (P <.05). The strain energy density in the load, steroid group was greater when compared to other groups (P <.05). CONCLUSIONS: Nandrolone decanoate and load acted synergistically to increase matrix remodeling and biomechanical properties of bioartificial tendons. CLINICAL RELEVANCE: Data suggest anabolic steroids may enhance production of bioartificial tendons and rotator cuff tendon healing in vitro. More research is necessary before such clinical use is recommended.