Why has the veterinary arthritis medicine Adequan not been approved for human use?

We recently put our aging lab onto Adequan injections (the company link is very equine-focused, but they have a canine formulation as well) to treat her arthritis, as the NSAIDS were raising her liver enzymes. We had heard about Adequan from a friend whose dog was on it—it basically extended the dog’s life (and useful, pain-free life) by two years. Many of the online testimonials point to it being a miracle drug, essentially causing the lame to walk and run again.

Why has this not been put into use for humans?

It seems obvious that it somehow didn’t pass FDA approval for humans, but I haven’t seen anything online as to why. (Most of what’s online is horse owners wondering why people can’t take it and steroid-using bodybuilders anonymously sharing stories of how they injected themselves with Canadian-purchased horse meds after some joint injury.)

Why no version for humans? Were there crazy reactions/side-effects? Would refining it for human use (it’s made from bovine tracheal tissue, apparently) take an unprofitable number of steps for the manufacturer? Seeing as how our population keeps aging, and how every drug company is eager to put anything new into the market, I can’t believe it wouldn’t sell like gangbusters if it worked even a fraction as well as it works in dogs and horses.

It seems to be glucosamine, right? I’m certainly not an expert, but I know my grandfather took it in powder form. I also know that doctors at the time said there was no evidence of it working - though it very obviously did. Same for my own old lab: she could jump into the back of the car if she was regularly taking glucosamine, could not jump into the back of the car if she wasn’t taking it. Difference clear as can be.

I don’t know about injections, though. And I don’t know about the FDA and don’t live in the US.

Examine has some info on glucosamine studies. They seem to say there is some benefit, but probably only minimally. For my dog, it was not minimally. The difference was huge.

Human drug trials cost boatloads of money and take years. No drug company is going to do that for something which is “generic”.

So you will not see any drug trials or new data on any herbal medicines or anything which is available in generic form.

If they can own a patent on the drug and charge $300 a bottle, then they will be HAPPY to do all sorts of drug trials!