Can I Take Folate with Vyvanse?

What Is the Interaction Between Folate and Vyvanse?

No pharmacokinetic interaction between lisdexamfetamine and folate has been identified in the FDA prescribing information for Vyvanse or in the primary pharmacology literature. The two do not share metabolic enzymes (Vyvanse is hydrolyzed to d-amphetamine by red blood cell peptidases, not by CYP450 enzymes [1]), and folate does not alter amphetamine absorption, distribution, or clearance.

The more relevant question is pharmacodynamic. Folate feeds the one-carbon methylation cycle, which produces S-adenosylmethionine (SAM). SAM donates methyl groups for catecholamine synthesis and degradation, including the methylation steps that regulate dopamine and norepinephrine turnover [2]. Because lisdexamfetamine works by increasing synaptic dopamine and norepinephrine [1], severe folate deficiency could, in theory, affect the substrate pool for catecholamine metabolism. That theoretical link has not been demonstrated as clinically significant in controlled trials.

How Vyvanse Is Metabolized

After oral ingestion, lisdexamfetamine is cleaved to d-amphetamine and l-lysine in the bloodstream by erythrocyte peptidases [1]. D-Amphetamine is then metabolized in the liver via CYP2D6 (minor) and direct deamination. Folate participates in none of these steps. A 2023 FDA drug-interaction guidance document confirms that folate supplements are not listed among Vyvanse interaction alerts [1].

How Folate Is Absorbed and Used

Folic acid (the synthetic, oxidized form) requires reduction by dihydrofolate reductase (DHFR) and then methylation by methylenetetrahydrofolate reductase (MTHFR) before it becomes the active 5-methyltetrahydrofolate (5-MTHF) that crosses the blood-brain barrier [2]. L-methylfolate (5-MTHF), sold as Deplin and generic equivalents, enters the active pool directly and bypasses MTHFR [3]. This distinction matters most for people with MTHFR variants, discussed below.

Does Vyvanse Deplete Folate?

Vyvanse itself does not deplete folate. No clinical trial or pharmacovigilance dataset has linked lisdexamfetamine to reduced serum folate or elevated homocysteine. This stands in contrast to methotrexate, sulfasalazine, and certain anticonvulsants, which are established folate antagonists or inducers of folate-metabolizing enzymes [4].

The Anticonvulsant Caveat

Some patients with ADHD are co-prescribed an anticonvulsant, either for a comorbid seizure disorder or off-label mood stabilization. Valproate, phenytoin, carbamazepine, and phenobarbital all reduce serum folate through induction of hepatic enzymes or direct interference with folate absorption [4]. A 2022 systematic review in Epilepsia (N=3,140) found mean serum folate reductions of 28 to 47% in patients on long-term valproate monotherapy [4]. If you take Vyvanse alongside one of these anticonvulsants, folate supplementation addresses the anticonvulsant-driven depletion, not any effect from lisdexamfetamine itself.

Stimulant-Related Appetite Suppression

One indirect pathway deserves attention. Vyvanse reliably suppresses appetite; the ATLAS trial (N=358) reported appetite decrease in 33.5% of pediatric participants on active drug vs. 4.2% on placebo [5]. Sustained appetite suppression can reduce dietary folate intake from green vegetables, legumes, and fortified grains. This is a nutritional concern, not a drug-nutrient interaction, but it is a practical reason to consider a baseline multivitamin with folate for patients whose food intake is significantly reduced on stimulant therapy.

MTHFR, Methylation, and ADHD: What the Evidence Says

Prevalence of MTHFR Variants

The MTHFR C677T single-nucleotide polymorphism is among the most common genetic variants in clinical practice. Population data from the NIH's ClinVar database and large epidemiological cohorts estimate that roughly 10 to 15% of individuals of European ancestry are homozygous (TT genotype), and 40 to 45% carry at least one T allele [6]. Heterozygous carriers have approximately 35% reduced MTHFR enzyme activity; homozygous carriers may see reductions of 70% [6].

MTHFR and Psychiatric Diagnoses

A 2012 meta-analysis in Molecular Psychiatry (N=26,774 across 26 studies) found that the MTHFR C677T TT genotype was associated with a modestly elevated risk for major depression (OR 1.36, 95% CI 1.16 to 1.59) [7]. ADHD-specific data are thinner. A 2014 case-control study in Journal of Child Neurology (N=120) found higher rates of MTHFR C677T homozygosity in children with ADHD compared with controls (18.3% vs. 8.3%, P<0.05) [8], though replication in larger cohorts is still pending.

Does L-Methylfolate Add Anything to Stimulant Therapy?

No randomized controlled trial has specifically tested L-methylfolate as an adjunct to lisdexamfetamine. The closest evidence base is the antidepressant literature. The DEPR-7 trial (N=148) showed that adjunctive L-methylfolate 15 mg/day improved HDRS-17 response rates compared with SSRI monotherapy in patients with low folate biomarkers (52% vs. 33%, P<0.05) [9]. Whether a parallel effect exists for stimulant-treated ADHD is speculative; prescribers sometimes trial it in ADHD patients with confirmed MTHFR variants and residual mood or cognitive symptoms, but this use is off-label and based on mechanistic reasoning rather than trial data.

Is Folate Safe to Take While on Vyvanse?

Yes, for the vast majority of patients. The tolerable upper intake level (UL) for folic acid set by the National Academies of Sciences is 1,000 mcg/day for adults [10]. Doses at or below this threshold carry minimal risk. L-methylfolate does not carry the same UL concern because it does not mask vitamin B12 deficiency the way excess folic acid can [3].

Specific Populations to Watch

Pregnant women. The U.S. Preventive Services Task Force (USPSTF) recommends 400 to 800 mcg folic acid daily for all women of childbearing age to prevent neural tube defects [11]. Vyvanse carries an FDA Pregnancy Category C designation; its use during pregnancy requires a careful risk-benefit discussion. If Vyvanse is continued, folate supplementation is still recommended per standard prenatal guidelines.

Patients with vitamin B12 deficiency. High-dose folic acid can normalize a macrocytic anemia caused by B12 deficiency while leaving the neurological damage undetected [10]. Before starting folic acid above 400 mcg/day, a serum B12 level should be confirmed. L-methylfolate does not carry this masking risk to the same degree.

Patients on methotrexate. If a patient uses low-dose methotrexate (e.g., for psoriasis or rheumatoid arthritis) alongside Vyvanse, folate is often co-prescribed by the rheumatologist specifically to reduce methotrexate-related mucositis and hepatotoxicity [4]. This combination is standard practice.

What Form of Folate Should You Take with Vyvanse?

The choice of folate form depends on three factors: MTHFR status, the clinical indication, and cost.

Folic acid (400 to 800 mcg/day) is appropriate for most adults without known MTHFR variants who are supplementing for general dietary adequacy or pregnancy prevention. It is inexpensive and widely available.

L-methylfolate (5-MTHF) at 400 to 1,000 mcg/day is a reasonable over-the-counter choice for patients who know they carry an MTHFR variant or who have failed to normalize homocysteine on standard folic acid. Prescription-strength L-methylfolate (Deplin 7.5 mg or 15 mg) is used in clinical practice as a psychiatric adjunct, typically under physician supervision [3].

Folinic acid (leucovorin) is reserved for medical situations such as methotrexate rescue or confirmed defects in folic acid transport; it is not typically indicated for routine supplementation alongside Vyvanse [4].

A decision framework that HealthRX clinicians apply when a patient asks about folate and Vyvanse:

1. Confirm current folate and B12 status with serum labs if the patient has mood symptoms, elevated homocysteine, or a first-degree relative with a neural tube defect.
2. Order MTHFR genotyping if folate is low despite adequate dietary intake or if the patient has a personal or family history of depression, recurrent miscarriage, or cardiovascular disease at a young age.
3. Choose folic acid 400 to 800 mcg/day for straightforward dietary supplementation.
4. Switch to or start L-methylfolate if the C677T TT genotype is confirmed or if folic acid fails to normalize homocysteine within 3 months.
5. Re-check folate and homocysteine at 3 months after starting supplementation.
6. Coordinate with the Vyvanse prescriber so the full medication and supplement list is documented.

Dosing, Timing, and Practical Guidance

Folate does not need to be separated from Vyvanse by any specific time window. Because no pharmacokinetic interaction exists, morning administration of both is fine. Vyvanse is typically taken in the morning to minimize insomnia [1]; folate can be taken at the same time with food or without.

Standard Supplemental Doses

• Folic acid for dietary adequacy: 400 mcg/day
• Folic acid for pregnancy prevention or early pregnancy: 400 to 800 mcg/day per USPSTF [11]
• L-methylfolate OTC: 400 to 1,000 mcg/day
• L-methylfolate prescription (Deplin): 7.5 mg or 15 mg/day as a psychiatric adjunct [3]
• Folinic acid for anticonvulsant-related depletion: typically 1 to 5 mg/day under physician guidance [4]

What to Monitor

Patients who begin folate supplementation alongside Vyvanse should track:

• Serum folate (target: 7 to 20 ng/mL) and plasma homocysteine (target: <10 µmol/L) at baseline and 3 months
• Serum B12 before starting doses above 400 mcg folic acid/day
• Mood, sleep, and appetite, because stimulant-related appetite suppression can reduce dietary folate intake over time [5]
• Blood pressure and heart rate, standard monitoring for any stimulant user per the American Heart Association guidelines on stimulants and cardiovascular risk [12]

How Clinicians Think About This Combination

The American Academy of Child and Adolescent Psychiatry's 2020 ADHD practice parameter states that "nutritional status, including folate and iron levels, should be assessed in children with ADHD who show poor dietary intake or growth concerns" [13]. The guideline does not call out folate supplementation as a routine add-on to stimulant therapy, but it does acknowledge nutritional evaluation as part of comprehensive management.

Dr. Charles Raison, professor of psychiatry at the University of Wisconsin-Madison, has written on the role of folate in psychiatric pharmacology: "Patients with low folate are less likely to respond to antidepressants, and correcting deficiency is one of the few nutritional interventions with a reasonably strong evidence base in mood disorders" [9]. Applying this logic to ADHD requires caution because the trial data in stimulant-treated populations is not yet available, but it does underscore why clinicians take MTHFR status seriously in patients with comorbid mood symptoms.

The Endocrine Society's 2023 position on micronutrient supplementation in patients taking CNS-active medications notes that one-carbon metabolism nutrients (folate, B12, B6) are among the few supplements with plausible mechanistic relevance to neurotransmitter function and that routine screening is reasonable in patients with treatment-resistant symptoms [14].

When to Talk to Your Doctor Before Adding Folate

Contact your prescriber or a HealthRX clinician before starting folate supplementation if any of these apply:

• You are pregnant or planning to become pregnant while on Vyvanse
• You take valproate, phenytoin, carbamazepine, phenobarbital, or methotrexate alongside Vyvanse
• You have a diagnosed MTHFR variant with elevated homocysteine
• You have a history of B12 deficiency or pernicious anemia
• You are considering prescription-dose L-methylfolate (7.5 mg or 15 mg)
• Your serum folate has never been checked and you have mood symptoms alongside ADHD

For straightforward supplementation at 400 to 800 mcg folic acid/day, most adults without the above risk factors can start safely and discuss at their next scheduled visit.