there's no reason to believe macromolecules like glucosamine benefit the body any more than regular, nutritious food. ingested nutrition generally gets broken down into amino acids and the like in the digestive system before it gets distributed to the rest of the body to be reconsistuted into cells and tissue.
cartilage in particular is scaffolding and generally must be constructed by other cells from very basic molecules at anchor points. it's decidedly not like lego blocks of glucosamine and chondroitin that just get assembled together.
As someone that has taken various vitamins and supplements over the years, glucosamine is the one where I truly feel a difference. In my knees, my back stopped cracking when I woke up, and generally just better. Others I take based on blood tests if something is out of whack for a time.
For me too.. And I'm usually extremely sceptical of food supplements and general quackery.
My joints have also been really cracky since I was a child. This seems a bit less but still present with the glucosamine.
But my elbow joints are often sore due to being on the computer way too much and every time I start taking it again it fades in a day or two. I don't think I'm imagining it :) Many other stuff I don't feel much benefit to.
Glucosamine supplementation doesn't appear to have harmful effects on humans and is pretty cheap. It may work for some people, so if you have joint issues why not give it a shot?
You raise a good point, but wouldnt taking glucosamine and chondroitin load you up (hopefully) on the base components required to then again make glucosamine and chondroitin locally in one's body?
“In the first study, glucosamine sulfate was given to healthy volunteers in doses of 750, 1500, or 3000 mg once daily. In the second study, oral glucosamine sulfate capsules (1500 mg) were given daily for two weeks to 12 people with osteoarthritis. Glucosamine concentrations in plasma and synovial fluid increased significantly from baseline levels […] but the levels are still ten- to a hundredfold lower than required to positively affect the cartilage (chondrocytes) to build new tissue”
⇒ the good news is that these molecules make it through the intestines intact, and arrive at the place where they are supposed to help. The bad news seems to be you would need to take huge doses.
cartilage in particular is scaffolding and generally must be constructed by other cells from very basic molecules at anchor points. it's decidedly not like lego blocks of glucosamine and chondroitin that just get assembled together.