From the GU site:
The biggest difference between Roctane Energy Gels and normal GU Energy Gels is more branch-chained amino acids (BCAAs) and the addition of the amino acids beta alanine and taurine. Roctane Energy Drink Mix also has a boosted supply of BCAAs and includes beta alanine and taurine. Meanwhile Roctane Electrolyte Capsules are a highly portable way to help you fight dehydration with high levels of sodium, vitamin D, vitamin B6, and ginger root to help prevent nausea.