NutriStack
Lisdexamfetamine and Vitamin C, timing-sensitive.
Lisdexamfetamine is converted to dextroamphetamine after absorption, and the active amphetamine exposure can be affected by urinary pH. High-dose Vitamin C as ascorbic acid may increase amphetamine clearance and reduce duration or intensity, although lisdexamfetamine absorption itself is less pH-sensitive than immediate-release amphetamine salts. The concern is mainly large supplemental doses or inconsistent timing, not normal vitamin C foods.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Lisdexamfetamine and Vitamin C
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Moderate
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Timing Sensitive · Moderate evidence
Timing Sensitive
What is happening. Lisdexamfetamine is converted to dextroamphetamine after absorption, and the active amphetamine exposure can be affected by urinary pH. High-dose Vitamin C as ascorbic acid may increase amphetamine clearance and reduce duration or intensity, although lisdexamfetamine absorption itself is less pH-sensitive than immediate-release amphetamine salts. The concern is mainly large supplemental doses or inconsistent timing, not normal vitamin C foods.
Mechanism. Lisdexamfetamine is a prodrug that produces systemic dextroamphetamine exposure. Amphetamine renal clearance is urine-pH dependent; acidifying conditions increase ionized amphetamine in renal tubules and can lower systemic exposure.
Recommendation. Avoid high-dose Vitamin C within 2 hours of lisdexamfetamine and keep your daily Vitamin C routine consistent. If you take gram-level Vitamin C, consider taking it later in the day and watch for shorter medication duration. Do not raise lisdexamfetamine doses without your prescriber if Vitamin C timing changes the effect.
Minimum separation. 120
Sources (3)
- Dolder PC, Strajhar P, Vizeli P, Hammann F, Odermatt A, Liechti ME. Pharmacokinetics and Pharmacodynamics of Lisdexamfetamine Compared with D-Amphetamine in Healthy Subjects. Front Pharmacol. 2017;8:617. PMID 28936175
- Wan SH, Matin SB, Azarnoff DL. Kinetics, salivary excretion of amphetamine isomers, and effect of urinary pH. Clin Pharmacol Ther. 1978;23(5):585-590. PMID 25157
- Huang W, Czuba LC, Isoherranen N. Mechanistic PBPK Modeling of Urine pH Effect on Renal and Systemic Disposition of Methamphetamine and Amphetamine. J Pharmacol Exp Ther. 2020;373(3):488-501. PMID 32198137
Stack Score
How this pair moves the number.
Effect on the composite score
If both Lisdexamfetamine and Vitamin C are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.