Q. My dog is 10 yrs old he's a pitbull and the weather is really cold. He's been a little slower and his legs are a bit stiff. Was wondering what to give
A. Joint supplements can make a world of difference when it comes to joint ailments and in my experience, their benefits have out weighed any side effects which are usually minimal. If your dog does have a reaction to these, its generally gastrointestinal upset (unless they have an allergy) which can be further reduced by decreasing the dose, or giving it with food, and in the beginning slowly weaning them on and up to the recommended dosages.
I would start there unless you think your dog needs some pain management if things are really bad. You would need to consult with your regular vet to determine what is the best course of action.
If you happen to be in Canada (like me) I would look up purica.com to see who retails Recovery SA in your area. I have had wonderful results with their powder.