Preventive use of glucosamine when running?

Question:
I’ve just ordered glucosamine from you, as advised by my doctor. I ended up with you because what I read seems trustworthy. My wife wonders whether this supplement can also be used preventatively (many sports, running).[chondroitine-links]

Answer:
Especially running can be quite stressful on the joints, so some extra protection can certainly do no harm. Glucosamine can be used preventatively to protect the cartilage, but personally we prefer chondroitin for that purpose.

Chondroitin is just as a powerful joint protector as glucosamine, but has no long term possible side effects. Glucosamine may have an impact on the blood sugar level with some people, such as unidentified diabetes, so with only preventative use we prefer chondroitin.

If there is existing osteoarthritis, accompanied by (morning) stiffness and pain, we recommend glucosamine because that product has a broader effect (except protecting the cartilage also joint lubrication and pain relief).