Synflex® offers two liquid Glucosamine products that are used specifically for dogs.
Synflex® 1500 should (not) be used for family pets. Yes, there is slightly more Glucosmine in that formula but it also contains White Willow Bark. White Willow Bark contains Salacin which is a chemical component of Salycitic Acid. It is sometimes used for anti-inflammatory properties. Salicin is also changed by your body to salycilic acid. There are undesirable side effects that could occur if using this chemically produced aspirin in pets.
Synflex® specifically recommends using either Synflex® Regular formula or Synflex® for Pets. (Beef flavored) .
This company just takes a more cautious route when dealing with family pets. Why take risks when the other two formulas do an excellent job.