I've not read that test decreases collagen synthesis. On the other hand, Var will increase it. Here's a study you may like:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1501119/
I'm recovering from a partial distal bicep tear myself. My doc scripted me var @ 20 mgs per day to help which I ran for 8 weeks. I'll be banking the rest of the 5 month script. Low dose, sure. Effective, I can only assume so as I'm healing up quite well.