I do not recommend mixing Sermorelin with HCG. While both drugs contain the same excipients (Mannitol) and pH buffers (Sodium Phosphate Monobasic and Sodium Phosphate Dibasic), their pH differs. Sermorelin has a maximum stability at or around a pH of 5. HCG has a maximum stability at or around 6.5. Increasing the pH of Sermorelin above 5.75 will also cause it to precipitate out of solution.