In their purest forms, glucosamine and chondroitin occur naturally within the human body. According to the University of Maryland Medical Center, both are essential elements of healthy cartilage. Supplementing natural levels of glucosamine and chondroitin with outside supplements is widely believed to help fight off the joint degeneration and arthritis of the joints that comes with aging, and the Mayo Clinic notes that certain studies support this for glucosamine, but Drugs.com notes that the FDA has not approved chondroitin for this purpose.
Vegetarian versions of glucosamine and chondroitin are available. The primary source for vegetarian glucosamine and chondroitin is algae. Labels should clearly indicate that algae is the primary source for the supplement for it to be certified vegetarian.
According to the University of Maryland Medical Center, a primary source for chondroitin supplements is cow cartilage. This can be used in powders or in injectible formulations of the supplement. Vegetarians may want to check with their doctors about the source of their supplements prior to accepting them to be sure whether they are from cows.
Sulfates are combined with glucosamine and chondroitin in the most common supplement formulations. According to the Wisconsin Department of Health Services, sulfates are natural salts that contain sulfur. The sulfur acts as a preservative, and while some people are concerned about side effects, the Wisconsin Department of Health Services notes that there are no known long-term health side effects.
Manganese is a trace mineral element that is commonly found in both glucosamine and chondroitin supplements, according to the Mayo Clinic. The Linus Pauling Institute notes that this element is both nutritionally essential and potentially toxic for the body.
On the nutritionally essential side of the equation, manganese is the principal antioxidant enzyme for the body's mitochondria. It is also required by the liver as it is involved in the way that the body metabolizes carbohydrates, amino acids and cholesterol. Manganese deficiencies can result in bone abnormalities, the Linus Pauling Institute notes, including joint problems, which is one contributing factor in its inclusion with glucosamine and chondroitin in supplements.
However, too much manganese is associated with neurological problems that include Parkinson's like tremors and psychiatric issues. The recommended intake levels for manganese are 2.3 mg per day for men and 1.8 mg per day for women, and those worried about the presence of manganese in their glucosamine and chondroitin supplements should seek out formulations without this element.