Glucosamine: Contained in JointGems. There have been no reported adverse reactions. In rare instances, some gastric discomfort was reported but was easily relieved by taking the supplement with food. Please consult your physician before using JointGems if you are pregnant, while nursing, for children under 2 years of age, or by persons on blood thinners such as Coumadin or Heparin. it is recommended that you inform your doctor when supplemeting.