My limping 8 year old boy...

So, my Flat Coated Retriever is limping from time to time. I have noticed this for the past month. I have been giving him Ester "C", Glucosamine&Chondroitin, and flaxseed added to his kibble every day. Some days the limping is gone...(maybe depending on the weather?), sometimes it's a full fledged limp...like he puts no pressure on his foot, and other times it's slight. I think he's aging, personally, and could require some arthritis medication. I hate to medicate a dog...especially because the meds are attached to all kinds of crap that might hurt him internally. I adore this dog...and can't see my life without him! Anyhow, I have checked between his toes and anything related to his foot...so that's DEFINATELY not it. I believe I feel a difference in the size of his knee compared to his other one. But I'm no vet... I don't think he's injured in any way. I could go for a second opinion by a vet...and I most certainly will, however I thought I would ask you well versed members FIRST...so, what do you all think it could be? Thanks in advance, ya'all! xoxoxox

since you don't mention an age for the dog I will assume he is of an age that one might expect arthritis and/or HD. In either event - the gludosimine, chondroiten, msm would be my recommendation altho I would not give the Ester C. I am not a fan of using the vitamin C as dogs unlike people DO manufacture their own. Are you sure you are giving him enough?

Suebgone, your so funny...the title of this question is: My limping 8 year old boy...lol. Anyhow, what is MSM? Also, I know that the canine manufactures their own vitamine C, however it is recommended for all patients of HD, (hip dysplasia), to take strong doses...as strong as the dog's stool will allow...(pull back just before soft stool). I was never a fan of vitamine C either till I saw the difference, the specialist at the DMV said it would make, and my dog that had hip dyplasia, (and had a T.P.O....), is doing amazing. The doc says that he HAS to do Condroitine&Glucosamine and Ester C for life. If a dog is not doing well with either cancer or hip dysplasia, often "shots" of Ester C is recommended. It's a life saver, really...I do need more options. Got any?