Can I Take Vitamin D with Vyvanse?

The prescription medication Vyvanse contains lisdexamfetamine dimesylate, a schedule II central nervous system stimulant that converts to dexamfetamine in the body. The FDA has approved Vyvanse for treating attention-deficit/hyperactivity disorder (ADHD) in children aged 6 and up, as well as for moderate-to-severe binge eating disorder in adult patients. Vitamin D encompasses two structurally similar forms: cholecalciferol (D3) and ergocalciferol (D2). These compounds are available without prescription as dietary supplements, though healthcare providers may recommend prescription-strength doses when deficiency has been identified.

There is no known pharmacokinetic interaction between vitamin D and lisdexamfetamine (Vyvanse). Lisdexamfetamine is cleared largely through hepatic CYP2D6 metabolism and monoamine oxidase activity after being converted to dexamfetamine, while vitamin D is processed through hepatic 25-hydroxylation and renal 1-alpha-hydroxylation, pathways that do not share enzymes or transporters with amphetamine clearance. The Vyvanse prescribing information does not list vitamin D as an interacting substance. What is worth tracking instead is vitamin D status itself: ADHD populations show a higher prevalence of low serum 25-hydroxyvitamin D than the general population, and appetite suppression from stimulant therapy can reduce dietary fat intake needed for vitamin D absorption, so periodic testing is a reasonable clinical practice independent of any drug interaction concern.

What the evidence actually supports

No published FDA label warning, case report, or major drug-interaction database entry documents a direct interaction between lisdexamfetamine and vitamin D. That absence is meaningful, but it also means the "no interaction" conclusion rests on the lack of a documented mechanism and lack of reported cases, not on a dedicated interaction trial. Nobody has run a controlled study specifically testing vitamin D alongside Vyvanse, so "no known interaction" should be read as "no established interaction based on mechanism and pharmacovigilance," not as "proven safe together by trial."

Lisdexamfetamine is inactive until red blood cell enzymes cleave it into dexamfetamine and L-lysine. Dexamfetamine is metabolized primarily by CYP2D6 and monoamine oxidase, with renal excretion sensitive to urinary pH. Vitamin D, by contrast, is absorbed in the small intestine as part of dietary fat, then hydroxylated in the liver (CYP2R1) and kidney (CYP27B1) to its active hormonal form. These are separate enzyme systems with no meaningful overlap at standard supplement doses. This is the pharmacological basis for treating the two as non-interacting, not a claim that has been tested head-to-head in humans.

Vitamin D absorption does depend on the presence of dietary fat, and Vyvanse absorption is not meaningfully affected by food according to its label. That difference is a practical dosing consideration, not a safety concern: taking vitamin D with a meal that contains some fat, at whatever time of day that occurs, is a reasonable approach, and there is no evidence that it needs to be timed relative to your Vyvanse dose.

Why vitamin D deficiency deserves separate attention in people on Vyvanse

Several observational studies have reported lower serum 25-hydroxyvitamin D concentrations in children and adults with ADHD compared with neurotypical controls. The National Institutes of Health Office of Dietary Supplements summarizes vitamin D deficiency risk factors and testing more broadly, including limited sun exposure, dietary restriction, and darker skin pigmentation, all of which apply regardless of ADHD status (NIH ODS vitamin D fact sheet). The specific magnitude of the ADHD-versus-control gap varies across the published studies we reviewed, and we are not confident enough in any single inherited citation to quote an exact percentage or mean difference here; a clinician relying on a specific number should verify it against the primary paper rather than take it from a secondary summary.

Appetite suppression is a well-documented effect of stimulant medications in this class, described in the Vyvanse label under adverse reactions. Reduced food intake, and particularly reduced fat intake, can lower passive absorption of fat-soluble vitamins including vitamin D. This is a plausible, mechanistically reasonable link between long-term stimulant use and vitamin D status, but it has not been established as a direct causal pathway in controlled trials. It is a reasonable clinical justification for periodic testing, not proof that Vyvanse itself depletes vitamin D.

Vitamin D's active hormonal form, calcitriol, has documented roles in regulating genes involved in dopamine synthesis and receptor expression in animal studies. Whether correcting vitamin D deficiency in humans meaningfully changes ADHD symptom severity or stimulant response has not been established by adequately powered randomized trials. Treat this as a plausible-but-unproven mechanism, not a reason to expect vitamin D to enhance or substitute for Vyvanse.

Bone health and appetite: the pediatric consideration

The Vyvanse label carries a warning about growth suppression with long-term stimulant use in children, which is an FDA-labeled concern independent of vitamin D. Because adequate vitamin D and calcium intake support normal bone mineral accretion in growing children, maintaining sufficient vitamin D status is a reasonable general pediatric health measure for any child on long-term stimulant therapy. We could not verify the specific pediatric bone-density study cited in earlier drafts of this article against its original source, so we are not repeating its numbers here; a pediatrician can advise on age-appropriate vitamin D dosing and whether additional bone-density monitoring is warranted for an individual child.

What is established, what is plausible, and what is not established

Established: Lisdexamfetamine and vitamin D are metabolized through separate enzyme systems, and the Vyvanse label does not list vitamin D as an interacting substance. Vitamin D deficiency is common enough in the general population, and in people with attention or mood symptoms, that testing is a reasonable clinical step regardless of stimulant use. The Endocrine Society's published thresholds for deficiency, insufficiency, and sufficiency of serum 25-hydroxyvitamin D are widely used in clinical practice.

Plausible but unproven: Vitamin D deficiency may be more prevalent in ADHD populations than in the general population, and appetite suppression from stimulant therapy may compound that risk by reducing fat intake needed for absorption. Vitamin D's role in dopamine-pathway gene regulation is real in preclinical models but has not been shown to meaningfully change stimulant treatment response in humans.

Not established: There is no trial evidence that vitamin D supplementation improves ADHD symptom control, reduces Vyvanse side effects, or allows for dose adjustment. There is no established need to separate vitamin D and Vyvanse dosing times. Precise prevalence figures for vitamin D deficiency in ADHD cohorts vary by study population and should be confirmed against the primary literature before being treated as a fixed statistic.

Evidence-status interaction assessment

What a clinician or pharmacist should verify before you rely on this for an individual decision: your current serum 25-OH vitamin D level and trend, your full supplement and medication list (especially anything alkalinizing urine, such as sodium bicarbonate or high-dose vitamin C, or anything with MAO or serotonergic activity), your Vyvanse dose and how long you have been on it, and, for children, growth and bone health monitoring already in place with the prescribing physician.

Supplements and substances that actually carry interaction risk with Vyvanse

Contrasting vitamin D with substances that do interact with lisdexamfetamine helps clarify why it is treated as low risk.

Urinary alkalinizers. Sodium bicarbonate, acetazolamide, and high-dose vitamin C can increase renal reabsorption of amphetamine, potentially raising blood levels. Urinary acidifiers such as ammonium chloride can do the opposite and reduce effectiveness. Standard vitamin D supplements have no documented effect on urinary pH.

MAO inhibitors. The Vyvanse label states that concurrent use with monoamine oxidase inhibitors is contraindicated because of the risk of hypertensive crisis, and specifies a washout period after stopping an MAOI before starting Vyvanse. Vitamin D has no MAO-related activity.

Serotonergic and stimulant-like supplements. Products such as 5-HTP or high-dose stimulant-containing herbal blends carry theoretical risk of additive CNS effects with Vyvanse. Vitamin D has no serotonergic or stimulant activity.

Practical points on testing and dosing

The correct test for vitamin D status is serum 25-hydroxyvitamin D, not the active hormone calcitriol, which can appear normal even when body stores are low. The Endocrine Society's published guidance defines deficiency as below 20 ng/mL, insufficiency as 20-29 ng/mL, and sufficiency as roughly 30-50 ng/mL; these thresholds are widely used but individual targets can vary by clinical context, so use them as a general reference rather than a personal dosing instruction. Levels generally take about 8-12 weeks to stabilize after a dose change, so retesting sooner than that can be misleading.

This article does not provide individualized dosing recommendations. Appropriate vitamin D repletion and maintenance doses depend on your baseline level, age, kidney function, and other medications, and should come from your prescriber or pharmacist rather than a general reference page.

When to seek urgent care

Vitamin D toxicity is rare at typical supplement doses and usually requires sustained very high intake over months. Symptoms of vitamin D toxicity (nausea, vomiting, weakness, frequent urination, confusion) or signs of a Vyvanse-related cardiovascular or psychiatric adverse effect (chest pain, fainting, severe agitation, hallucinations, uncontrolled blood pressure) warrant prompt medical evaluation rather than self-management, regardless of what supplements you are taking.