Hi, Nitro-Tech is a protein supplement used by bodybuilders to aid muscle growth and recovery after exercise. The most common side effects reported with Nitro-Tech are gastrointestinal symptoms such as bloating, gas, and diarrhea. Some people may also experience allergic reactions or skin rashes. However, feeling sleepy, sick, and having a headache may not be directly related to Nitro-Tech. It s possible that these symptoms could be due to other factors such as dehydration, low blood sugar, or stress. As for your blood pressure, a slight decrease in blood pressure after a few minutes is normal and can be caused by many factors, including changes in posture or stress. However, if you continue to feel unwell, it s best to speak with your healthcare provider to rule out any underlying health issues. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician