Measurement of NAD+ Synthesis in Human Skeletal Muscle

Nicotinamide adenine dinucleotide (NAD) is a vitally important substance that is found in all cells of the body. D4-NAM (in normal saline) will be infused via an indwelling catheter.The IV infusion will continue for 8 hrs.

Participants will have a muscle biopsy performed on the muscle in the thigh. We will collect a small sample of blood before the biopsy. This procedure is used to sample muscle cells from the right or left leg Vastus Lateralis (thigh) muscle.

This procedure is used to sample skin tissue from the upper thigh via a punch biopsy.