There are five types of Glucosamine:
1. D-Glucosamine Hydrochloride (HCL) – (from Shellfish or vegetables)
2. D-Glucosamine Sulphate 2KCl – (from Shell)
3. D-Glucosamine Sulphate NaCl
4. N-acetyl-glucosamine (NAG)
5. Poly N-acetyl-glucosamine (NAG Poly)
Note: the technical Names for Glucosamine is "D-Glucosamine" (except for no. 4 and 5 above)