L-Threonic Acid Magnesium Salt (L-TAMS) in ADHD

Inclusion Criteria: * Male or female adults ages 18-55 years of age * A diagnosis of childhood-onset Attention Deficit/Hyperactivity Disorder (ADHD), meeting the Diagnostic and Statistical Manual, Fifth Edition (DSM-V) criteria for ADHD in adulthood, including at least 5 current symptoms of inattentive or impulsive-hyperactive traits, and childhood onset by age 12, defined as two symptoms of inattentive or of impulsive/hyperactive traits by the age of 12 * A score of 20 or more on the Adult ADHD Investigator Symptom Report Scale (AISRS), and, for those individuals stably treated with stimulants, a Clinical Global Impression -ADHD (CGI-ADHD) severity score of no greater than 4 ("moderately ill") * Subjects on a stable dose of stimulant medication must be treated on the same dose for at least 1 month prior to study entry Exclusion Criteria: * A history of intolerance to magnesium supplementation, or the ingredients in MMFS202 (6-hour release) AND MMFS302 (12-hour release) * Pregnant or nursing females * A known unstable medical illness including hepatic, renal, gastroenterological, respiratory, cardiovascular (including hypertension ≥ 140/90 mmHg at screening), endocrinologic (e.g. thyroid), neurologic (e.g. seizure), immunologic, hematologic, or psychiatric (other than ADHD) disorder); individuals with kidney dysfunction will be excluded, as dysfunctional kidneys may have difficulty clearing the magnesium from the body (which can result in dangerously high magnesium levels); individuals with heart block will be excluded from the study * Any medical condition that the Principal Investigator (PI) believes will be exacerbated by study participation * A history of cancer (except localized skin cancer without metastases or in situ cervical cancer) within 5 years prior to screening * A known history of narrow-angle glaucoma * Current (within 3 months) DSM-V criteria for abuse or dependence with any psychoactive substance other than nicotine * Intelligence Quotient (IQ) less than 80 (based on the Wechsler Abbreviated Scale of Intelligence-II Full Scale IQ calculation) * Multiple adverse drug reactions * Any other concomitant medication with primarily central nervous system activity as specified in the study protocol * Current use of a monoamine-oxidase inhibitor (MAOI) or use within the past two weeks * Current use of antibiotics, as the study agent may reduce the absorption of antibiotics * Subjects may not take any of the following substances for at least 7 days prior to baseline and throughout the study: Calcium channel blockers; any psychoactive medications; any medications known to interact with magnesium; supplemental magnesium or any magnesium-containing products; all dietary or herbal supplements or products including those purported to improve memory, improve sleep, or decrease stress. * Investigator and his/her immediate family; defined as the investigator's spouse, parent, child, grandparent, or grandchild