They are designed to work together synergistically. Either step may be taken with no ill effects, but to attain the optimum results we recommend both steps. HF37 will only affect the rate of growth on scalp hair. No natural supplements are FDA approved. Sites that offer supplements that say they are FDA approved are not telling you the truth.
Many people report improvement in their skin too.
Felt like they had a sunburn or a tingling sensation about 30-45 minutes This is due to niacin and is a benefit of niacin. It is involved in the normal formation of stomach fluids and secretion of bile, along with the synthesis of the sex hormones. It dilates the blood vessels and brings blood to the surface of the skin. It lowers triglycerides, cholesterol and is considered helpful for schizophrenia and other mental illnesses. It is harmless, diminishes after 30 minutes or so, and can be reduced by taking niacin with a meal and an extra glass of water.