If the MSM stops workin, you might consider givin Apple Cide Vinegar a try.
Apple Cider Vinegar ( not any other kind), best if it is Organic and with 'The Mother'.
Do at least 1 ACV (apple cider vinegar) drink a day. 2x is better...
8 oz glass of water, add 2 tables spoons of ACV (I gotten to taking a fairly strong dose without measuring).
You can add sweeteners (Fruit, stevia are OK, but not Aspartame, to kill some of the acv taste. But one quickly gets accustomed to the taste.
I had a fairly serious achilles injury, which after a year of various treatments, nothing helped at all.
I started taking ACV daily and within 3 weeks I started to notice small improvement. Within 3 months the achilles was as 'normal' as the other side.
worked for me, and from what investigation shows, a lot of people