1. IGF-1 (Insulin-like Growth Factor-1): A hormone produced in the liver in response to HGH. It mediates many of HGH's anabolic effects, such as promoting cellular growth, protein synthesis, and bone density, while also contributing to recovery and tissue repair.

2. Titration: The process of gradually adjusting the dosage of HGH for optimal effects while minimizing side effects. For example, starting with 2 IU daily and slowly increasing by 1 IU every 2–3 weeks.

3. HGH (Human Growth Hormone): A peptide hormone secreted by the pituitary gland responsible for promoting growth, cellular repair, and metabolism.

4. Pulsatility: The natural release pattern of HGH in bursts or pulses, particularly during deep sleep or intense exercise, as opposed to constant secretion. HGH timing often mimics this natural process.

5. Negative Feedback: A mechanism in which elevated levels of IGF-1 signal the pituitary gland to reduce HGH secretion, maintaining a hormonal balance. This feedback is less pronounced with exogenous HGH use.

6. Subcutaneous (SubQ): An injection method where HGH is administered into the fatty tissue just beneath the skin. This method is commonly used for its ease of self-administration and slower absorption rates.

7. Intramuscular (IM): An injection method where HGH is directly delivered into muscle tissue. This allows for faster hormone absorption but can be more painful and technically challenging.

8. Lipolysis: The breakdown of fats into glycerol and free fatty acids, which HGH promotes to reduce fat stores and use fat for energy.

9. Hypertrophy: The enlargement of muscle cells, often associated with resistance training and HGH's anabolic effects on protein synthesis and muscle repair.

10. Insulin Resistance: A condition where cells become less responsive to insulin, potentially leading to elevated blood sugar levels. HGH can antagonize insulin's effects, making monitoring blood sugar and insulin sensitivity important.