HGH is relatively benign in the side effects department.
Possible side effects of HGH use include:

*nerve, muscle, or joint pain
*swelling due to fluid in the body's tissues (edema)
*carpal tunnel syndrome
*numbness and tingling of the skin
*high cholesterol levels

Possible side effects of caffiene:

*stomach pain, tenderness, bloating,
*constipation or diarrhea;
*green-colored vomit;
*blood in the stools;
*unusual weakness;
*seizure (convulsions);
*twitching or uncontrolled muscle movements; or
*fever, fast or slow heart rate.