BackgroundChondroitin was first extracted and purified in the 1960s. It is currently manufactured from natural sources (shark/beef cartilage or bovine trachea) or by synthetic means. The consensus of expert and industry opinions supports the use of chondroitin and its common partner agent, glucosamine, for improving symptoms and stopping (or possibly reversing) the degenerative process of osteoarthritis. Dosing NB! The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy. Adult (18 years and older) Doses of 200-400 milligrams by mouth twice to three times daily, or 800-1,200 milligrams once daily have been used in studies. Higher doses (up to 2,000 milligrams) appear to have similar efficacy. In the treatment of osteoarthritis, full effects may take several weeks to occur. It is not clear what dose is optimal when used in combination with glucosamine or whether the combination is as effective as or more effective than either agent alone. For osteoarthritis, 50-100 milligrams as a single daily injection or divided into two daily injections has been used. Medical supervision is recommended. Children (younger than 18 years) There is no proven effective dose for chondroitin in children. Safety NB! There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects. Allergies Use cautiously if allergic or hypersensitive to chondroitin sulfate products. Use cautiously in patients with shellfish allergy, due to the possibility of allergic reaction. Hives, rash, sun skin sensitivity, and worsening of previously well-controlled asthma have been reported. Side Effects and Warnings Chondroitin sulfate appears to be well tolerated for up to three years. Adverse effects that have been rarely reported or are theoretical include: headache, motor uneasiness, euphoria, hives, rash, photosensitivity, hair loss, breathing difficulties, subjective tightness in the throat or chest, exacerbation of previously well-controlled asthma, chest pain, elevated blood pressure, lower extremity edema, gastrointestinal pain/dyspepsia, nausea, diarrhea, constipation, transaminitis, increased risk of bleeding (theoretical), bone marrow suppression (animal research), and eyelid edema. Avoid in individuals with prostate cancer, or at increased risk for prostate cancer, due to a risk of increased spread or recurrence of prostate cancer. Pregnancy and Breastfeeding Avoid in pregnant or breastfeeding women as effects are unknown, and there is structural similarity to heparin, a blood thinner that is contraindicated during pregnancy.