To learn how altered metabolism in GBM causes tumor growth and resistance to drug therapy. In this pilot research study, we will dose GBM patients with a form of nicotinamide (a natural vitamin) that we can track. The nicotinamide will be converted to methyl nicotinamide (MeNAM) in the tumor. We will measure how fast the nicotinamide is converted to methyl nicotinamide. We believe that the speed of this chemical reaction in the tumor (fast versus slow) may be correlated with GBM aggressiveness

Inclusion Criteria:

1. Preoperative MRI consistent with a primary intracranial malignant brain tumor.
2. Must be 18 years of age or older.
3. Patient eligible for debulking surgery/resection.

Exclusion Criteria:

1. Inability to obtain pre-operative IV access.
2. Use of Tru Niagen, Basis (or any other nicotinamide riboside (NR)-containing NAD+ booster) or niacin supplements within one month prior to Study Visit 1.
3. Participation in studies involving investigational drug(s) within 30 days prior to Study Visit 1
4. Blood donation (excluding plasma donations) of approximately 1 pint (500 mL) or more within 56 days prior to Study Visit 1 (participants may not donate blood any time during the study, through the final study day)
5. Presence of any condition that, in the opinion of Dr. Field, compromises participant safety or data integrity or the participant's ability to complete study days.
6. Pregnancy, lactation or < 9 months postpartum from the Study Visit 1 date.

The research being pursued in this study is relevant to all GBM patients including these who are cognitively impaired.