This liquid vegetarian glucosamine contains no shellfish, thus people with that sensitivity can take this product. It is enhanced with MSM, which is a sulfur product, so if you are sensitive to sulfur you might prefer Glucosamine HCl (no sulfur or shelfish). Glucosame is the only nutrient that can help repair cartilage; cartilage is there to cushion joints, including spinal discs, and can be worn down from use or injury. Many people know the severe pain this can cause to the knees when the cartilage there is worn away or to the back as spinal discs become worn. This is the best product we sold in the store for these problems.