Here some research studies that were conducted about the efficacy of the supplements:
Kim LS, et al. Efficacy of methylsulfonylmethane (MSM) in osteoarthritis pain of the knee: a pilot clinical trial. Osteroarthritis and Cartilage. 2006; 14: 286-294.
Uebelhart D, et al. Effects of oral chondroitin sulfate on the progression of knee osteroarthritis: a pilot study. Osteroarthritis and Cartilage. 1998: 6: 39-46.
Magrans-Courtney T, et al. Effects of diet type and supplementation of glucosamine, chondroitin and MSM on body composition, functional status, and markers of health in women with knee osteroarthritis initiating a resistance-based exercise and weight loss program. Journal of the International Society of Sports Nutrition. 2011; 8:8.
Xu G, et al. Evaluation of the effect of Mega MSM on improving joint function in populations experiencing joint degeneration. International Journal of Biomedical Science. 2015; 11(2): 54-60.
Durmus D, et al. Assessment of the effect of glucosamine sulfate and exercise on knee cartilage using magnetic resonance imaging in patients with knee osteoarthritis: A randomised controlled clinical trial. Journal of Back and Musculoskeletal Rehabilitation. 2012; 25: 275-284.