The short answer
The reviewed sources do not establish that amphetamine sulfate changes how much L-glutamic acid you need or when to take it. EVEKEO names glutamic acid hydrochloride, a distinct acidic salt, in its interaction warning. That warning does not by itself establish an interaction with plain L-glutamic acid. No human study of the exact combination or supported timing interval was identified.
What this answer covers
Plain L-glutamic acid (also called L-glutamate) supplements taken by mouth with amphetamine sulfate in EVEKEO tablets or as one ingredient in ADDERALL and ADDERALL XR. Glutamic acid hydrochloride and other specific glutamate salts are distinct preparations and are not established by this article.
- Supplement or preparation
- L-glutamic acid
- Medication ingredient
- amphetamine sulfate
What the label names, and what it does not
The EVEKEO label lists glutamic acid HCl among gastrointestinal acidifying agents that lower the absorption of amphetamines. That is the hydrochloride salt, a preparation whose purpose is to add acid to the stomach. Plain L-glutamic acid, L-glutamate and monosodium glutamate are not named in the label. The current ADDERALL tablet label has dropped the named chemicals altogether and refers only to gastrointestinal and urinary acidifying agents as categories.
Why the two are not interchangeable
The hydrochloride salt and plain amino acid are distinct preparations. A warning that names one cannot establish the effect of the other from their shared name alone. The reviewed human urinary-pH literature did not include an L-glutamic acid intervention, and it did not assess the stomach-acidity mechanism in the EVEKEO warning. This leaves the effect uncertain rather than showing that plain L-glutamic acid has no effect.
Nothing addresses your glutamic acid needs or timing
No inspected source states that amphetamine sulfate changes a person's L-glutamic acid requirement or establishes a supplement timing interval. The pharmacokinetic review provides general context for amphetamine and urinary pH but does not study this supplement combination.
A reasonable approach
Tell the prescriber and pharmacist about any amino acid supplement you take, and read the product label to see which form it actually contains, since glutamic acid hydrochloride is a separate product from plain L-glutamic acid. If you use a product that does contain the hydrochloride salt, that is the one the amphetamine label addresses, and it is worth raising specifically.
Evidence and practical considerations
Timing & monitoring
No inspected source establishes altered L-glutamic acid requirements or a timing interval during amphetamine sulfate treatment. EVEKEO names the distinct hydrochloride salt as a gastrointestinal acidifier; the current ADDERALL tablet label uses acidifying-agent categories. Neither establishes an interaction for plain L-glutamic acid.
- Exact scope
- Plain L-glutamic acid, also called L-glutamate; the finding does not establish effects for the hydrochloride or other specific salts. with Oral amphetamine sulfate, both as the single-entity tablet (EVEKEO) and as one of the four salts in mixed amphetamine salts products (ADDERALL tablets and ADDERALL XR capsules).
- Medication form and route
- oral medication; oral supplement
What remains uncertain
- No human study of this pair was identified in the reviewed searches, and no human trial of L-glutamic acid on urinary or gastric acidity was located, so the amount of acid such a supplement adds is unknown rather than shown to be trivial.
Factors that may matter: Exact salt or form in the product; Dose; Whether the product is taken with food; Other acidifying products.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 22, 2026
Population: People prescribed amphetamine sulfate
The Drug Interactions section names glutamic acid HCl, the hydrochloride salt, among gastrointestinal acidifying agents that lower absorption of amphetamines. Plain L-glutamic acid, L-glutamate salts and monosodium glutamate are not named anywhere in the label.
How this applies: Exact amphetamine sulfate label. It names glutamic acid hydrochloride, a different preparation from this article's plain L-glutamic acid, so it provides an identity boundary rather than direct evidence for this pair.
The label names one specific salt and gives no dose, no effect size and no statement about the free amino acid.
Source 2: current product label
dailymed.nlm.nih.gov · Source check Sep 22, 2026
Population: People prescribed amphetamine sulfate
The current interaction table states only that acidifying agents lower blood levels and efficacy of amphetamines and that the dose should be increased based on clinical response. Its examples are the categories gastrointestinal acidifying agents and urinary acidifying agents. This label no longer names glutamic acid HCl, ascorbic acid, fruit juices or sodium acid phosphate.
How this applies: Amphetamine sulfate (RxCUI 81952) is one of the four salts in ADDERALL immediate-release tablets. The class interaction statement applies to the mixed-salt product; it does not isolate one salt or establish the effect of every supplement.
The generic class wording means the label decides nothing about whether any particular amino acid supplement belongs in the class.
Source 3: systematic literature review of human trials
ebi.ac.uk · Source check Sep 22, 2026
Population: Adults and children aged 6.5 to 76.5 years across 150 experiments and 2,895 participants
The review compiled 150 experiments on urinary pH from 86 human studies. L-glutamic acid and glutamate salts are absent from its intervention table. It lists glycine/L-tryptophan among alkalinizing interventions and methionine among acidifying interventions; these different amino acids do not establish an effect for glutamic acid.
How this applies: The review did not include L-glutamic acid or glutamate interventions. This is a limited negative search finding, not proof of no effect and not evidence about gastrointestinal acidity.
Literature review of urinary pH studies searched through September 2023, with heterogeneous designs, populations and pH measurements. It does not test gastric acidity or amphetamine pharmacokinetics. An intervention missing from the review is not proof that no study exists.
Source 4: pharmacokinetic review
pubmed.ncbi.nlm.nih.gov · Source check Sep 22, 2026
Population: Children, adolescents and adults taking amphetamine formulations.
Oral amphetamine is rapidly absorbed with high bioavailability, immediate-release products reach peak concentration in 2 to 3 hours, and the review states that there are few documented pharmacokinetic drug interactions of clinical significance beyond the influence of drug-induced changes in urinary pH.
How this applies: Places the urinary pH mechanism in context for the marketed amphetamine products, including those containing amphetamine sulfate. It is a review rather than an original measurement.
Narrative pharmacokinetic review read as an abstract. It does not test or quantify any dietary supplement.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Editorial update | |
| Editorial source audit clarified label scope, evidence limits and practical wording. No clinical approval was recorded. | |
| Research summary published | |
| Article prepared | |
| Prepared exact amphetamine sulfate and L-Glutamic acid article from inspected current labeling and original sources, with uncertainty stated. |
Article revision: 48183dba12bdfebc
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.