I started using it this summer for my low back pain. I went to a local medical cannabis clinic to get a prescription and they handed me a list of Canadian suppliers. I had first tried it from the government agency (SQDC) that sells cannabis in Quebec but the quality or the dosage was too low (wasn't full spectrum either) and I didn't really get any benefits. I ended up getting organic full spectrum oils from The Green Organic Dutchman.
From what I understand, full spectrum oils (that have all the terpenes, secondary molecules) are more effective (as opposed to powdered pure CBD extract added to oil). If it's CBD only (trace THC) I can drive and operate machinery after taking the oil. That was a huge selling point for me, I needed something that I could take while at work, since most of my back pain was from work. I also took some recently with my knee tendon issues. This time it's a bit harder to tell how effective it was because so much of the pain/irritability comes from my daily activities, but I still felt like it helped forget the pain throughout the day. Mostly it took the pain down a couple of notches, from 4-5 on a 1-10 scale to as low as 1-2. When I was low pain 1-3, it could completely eliminate it. I didn't have severe back spasms that prevented me from working/walking this year so I can't say how effective it would be with a 8-9 pain level.
Dosage seems to be important, I had little to no effects until I reached about 25-30mg. Usually I take only one dose, but sometimes I needed a second one about 8-10 hours after the first one. It seems that dosages will vary a lot depending on your personal endo-cannabinoid system (from what the doctor at the local clinic told me).
I had someone on here from another forum discussion recommend these suppliers.
Sunsoil - Organic CBD Oil Drops & Capsules (formerly Green Mountain)
CBDistillery | CBD Oil for Sale Online | Lab-Tested U.S. Hemp (thecbdistillery.com)
Feel free to reach ou if you have any more questions.