A few months ago I started taking gelatin for creaky joints and slightly painful knees. I took a teaspoon a day, but that seemed to cause constipation. So I halved it. I put 1/2 teaspoon of the grainy looking stuff of fish gelatin, in a bit of cold water, let it "bloom" (swell) for about 1/2 hour, then added hot water to melt it and drank it as is. I've been doing this almost daily.
I recently went back to an exercise class that I haven't been to in 8 weeks, and I was astonished that NOTHING CREAKED! As different from other times that I missed these classes. My neck is far more flexible too.
When I told someone else, a few DAYS after I started this, that I imagine my knees are complaining less when I bound down my five flights of stairs, he started taking a marshmallow or two a day ("it has gelatin, right?! ")....and also reported a difference! He now takes the gelatin as homemade jello with fruit juice.
Knox Gelatin cured my bursitis of the shoulders. it works on the joints. i mixed the gelatin in a glass of grapefruit juice. then drink up.