L-Tyrosine 1000 mg Ingredients & Drug Interactions
by GNC
What is this page for?
First and foremost: checking L-Tyrosine 1000 mg against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.
Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy
L-Tyrosine 1000 mg is a dietary supplement by GNC with 1 active ingredient. Its ingredients are commonly taken for mental focus and alertness, coping with stress, fatigue and sleep loss.Based on those ingredients, 21 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Tyrosine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against L-Tyrosine 1000 mg by GNC
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Tyrosine 1000 mg by GNC — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of L-Tyrosine 1000 mg by GNC
Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.
What’s inside
Full disclosure
This product contains one active ingredient: L-tyrosine at 1000 mg per dose. Tyrosine is an amino acid your body normally makes, and it serves as a precursor — a chemical building block — for several important compounds, including dopamine and thyroid hormones.
The inactive ingredients are cellulose and food glaze, which are common binders and coatings.
Does it work?
Strong evidence
The evidence for tyrosine is mixed. It's considered effective for phenylketonuria (PKU), a rare genetic condition where the body can't process another amino acid properly.
For cognitive function and memory, the evidence is possibly effective — meaning there's some promise, but we'd like to see more research. Athletic performance, on the other hand, is rated possibly ineffective.
The evidence for alcohol use disorder and dementia isn't established well enough to rate either way.
How safe is it?
Well-documented data
Tyrosine is generally well tolerated in healthy adults, but there isn't enough safety data to recommend regular use without a doctor's guidance. The most common side effects reported are fatigue, headache, heartburn, and nausea.
Larger doses (around 150 mg per kilogram of body weight) increase the risk of headache and fatigue. There isn't enough safety data on tyrosine during pregnancy and lactation, so talk with your doctor or pharmacist if you're pregnant, trying to become pregnant, or breastfeeding before you use this supplement.
Meds to double-check
Moderate interaction found
Check with your doctor or pharmacist if you take levodopa (Moderate severity interaction — separate doses by at least 2 hours) or thyroid hormone medications like levothyroxine (Moderate severity, potential additive effect). These are the medication types with documented interactions in our data.
The bottom line
Scorecard at a glanceFully disclosed formula with strong clinical evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.
L-tyrosine may be worth considering if you're looking to support cognitive function or memory, though the evidence is still limited. If you take levodopa for Parkinson's disease or thyroid hormone medications, you'll need to check with your doctor or pharmacist first — the interactions are documented and real.
A healthy person without those medications who tolerates it well can usually take it, but start with your own healthcare provider to make sure it fits your situation.
Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI
Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Oct 26, 2011.
This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed
General information
Key facts about L-Tyrosine 1000 mg, straight from the product label.
| Brand | GNC |
|---|---|
| Barcode (UPC) | 048107061470 |
| Net contents | 60 Vegetarian Caplet(s) |
| Market status | On market |
| Date entered into DSLD | Oct 26, 2011 |
| DSLD ID | 1440 |
| Product type | Amino Acid/protein |
| Supplement form | Other (e.g. Tea Bag) |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years) |
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.
Supplement Facts
The label details for L-Tyrosine 1000 mg by GNC, sourced from the NIH Dietary Supplement Label Database.
Tap any ingredient to jump to its full detail below.
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
FDA Disclaimer Statement
This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
FDA Statement of Identity
DIETARY SUPPLEMENT
Formula
Ko
Formulation
No Sugar, No Starch, No Artificial Colors, No Artificial Flavors, No Preservatives, Sodium Free, No Wheat, No Gluten, No Corn, No Soy, No Dairy, Yeast Free.
Precautions
KEEP OUT OF REACH OF CHILDREN
Storage
Store in a cool, dry place.
General Statements
1000 mg
ACTUAL SIZE
For more information:
Lot No./Best By:
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supports normal, healthy nervous system activity
General
CODE 128212 ALG
Suggested/Recommended/Usage/Directions
Directions: As a dietary supplement, take one to four caplets daily on an empty stomach.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Tyrosine 1000 mg by GNC label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.
View the full label (PDF)The Ingredients in L-Tyrosine 1000 mg by GNC
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Caplet(s) Dosage formOther (e.g. Tea Bag) Amounts shown are per serving.
L-Tyrosine
Interacts with21 drugs
L-tyrosine is an amino acid your body uses to make brain chemicals like dopamine and norepinephrine. Some studies suggest it may help mental performan...
L-Tyrosine monograph & interactionsOther (inactive) ingredients: Cellulose, Food Glaze. These complete the product’s ingredient list but are not active constituents.
L-Tyrosine 1000 mg by GNC Drug Interactions
HelloPharmacist Interaction Report
GNC's L-Tyrosine 1000 mg can interact with two medication types.
The most serious concern is with levodopa (used for Parkinson's disease) — tyrosine and levodopa compete for absorption in your small intestine, and this interaction carries Moderate severity. The supplement may also interact with thyroid hormone medications at Moderate severity, since tyrosine is a building block for thyroid hormones and might push levels higher than intended.
Read the full breakdown — every affected drug type, severity by severity
Altogether, these interactions span 21 individual medications.
With levodopa, the effect is straightforward: tyrosine could reduce how well the drug works. If you take it, separate your tyrosine dose and your levodopa dose by at least two hours.
With thyroid hormones, tyrosine might add to their effect, potentially raising hormone levels too high. Either way, talk to your doctor or pharmacist about your exact medications before you start.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Tyrosine 1000 mg?
Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.
Go to the checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in L-Tyrosine 1000 mg interact with 21 drugs. Click any drug to see the details.
1 of the 1 ingredient in L-Tyrosine 1000 mg interact with drugs. Each result below shows which ingredient is responsible. L-Tyrosine
Benserazide, LevodopaMadopar, Prolopa
How Benserazide, Levodopa interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Benserazide, Levodopa interactionCarbidopa, LevodopaDhivy, Rytary, Sinemet, Sinemet CR
How Carbidopa, Levodopa interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Carbidopa, Levodopa interactionCarbidopa, Levodopa, EntacaponeStalevo
How Carbidopa, Levodopa, Entacapone interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Carbidopa, Levodopa, Entacapone interactionConjugated EstrogensCenestin, Enjuvia, Premarin, Premarin Vaginal Cream
How Conjugated Estrogens interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Conjugated Estrogens interactionDesiccated Thyroid ExtractWesthroid, WP Thyroid
How Desiccated Thyroid Extract interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Desiccated Thyroid Extract interactionDesiccated Thyroid Extract (prescription Drug)Nature-Throid, Thyrar
How Desiccated Thyroid Extract (prescription Drug) interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Desiccated Thyroid Extract (prescription Drug) interactionDextrothyroxineCholoxin
How Dextrothyroxine interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Dextrothyroxine interactionHuman Chorionic Gonadotropin (hcg)Pregnyl
How Human Chorionic Gonadotropin (hcg) interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Human Chorionic Gonadotropin (hcg) interactionLevodopaInbrija, Larodopa
How Levodopa interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Levodopa interactionLevodopa, CarbidopaDuodopa
How Levodopa, Carbidopa interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineLevodopa Moderate
Interaction Summary
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Read the full L-tyrosine + Levodopa, Carbidopa interactionLevothyroxineEltroxin, Estre, Euthyrox, Levo-T, Levolet, Levothroid +5 more
How Levothyroxine interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Levothyroxine interactionLevothyroxine SodiumErmez, Thyquidity, Tirosint-Sol
How Levothyroxine Sodium interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Levothyroxine Sodium interactionLevothyroxine, LiothyronineArmour Thyroid
How Levothyroxine, Liothyronine interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Levothyroxine, Liothyronine interactionLiothyronineCytomel
How Liothyronine interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Liothyronine interactionLiotrixEuthroid 1, Euthroid 1/2, Euthroid 3
How Liotrix interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Liotrix interactionLiotrix, T4/t3Euthroid 2
How Liotrix, T4/t3 interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Liotrix, T4/t3 interactionMenotropinsMenopur, Repronex
How Menotropins interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Menotropins interactionOspemifeneOsphena
How Ospemifene interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Ospemifene interactionTestosterone UndecanoateAndriol, Aveed, Jatenzo, Kyzatrex
How Testosterone Undecanoate interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Testosterone Undecanoate interactionThyroglobulinProloid
How Thyroglobulin interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Thyroglobulin interactionThyroid HormoneEtwon
How Thyroid Hormone interacts with L-Tyrosine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-tyrosineThyroid Hormone Moderate
Interaction Summary
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Read the full L-tyrosine + Thyroid Hormone interactionEach ingredient & the kinds of drugs it affects
For each ingredient in L-Tyrosine 1000 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.
L-Tyrosine
Levodopa
Theoretically, tyrosine might decrease the effectiveness of levodopa.
Tyrosine and levodopa compete for absorption in the proximal duodenum by the large neutral amino acid (LNAA) transport system. Advise patients to separate doses of tyrosine and levodopa by at least 2 hours.
Thyroid Hormone
Theoretically, tyrosine might have additive effects with thyroid hormone medications.
Tyrosine is a precursor to thyroxine and might increase levels of thyroid hormones.
Brand information
Manufacturer and brand details for L-Tyrosine 1000 mg, from the product label.
GNC
See all GNC products- Name
- General Nutrition Corporation
- City
- Pittsburgh
- State
- PA
- ZipCode
- 15222
- Phone Number
- 1-888-462-2548
- Web Address
- gnc.com
L-Tyrosine 1000 mg by GNC: Common Questions
Does L-Tyrosine 1000 mg by GNC interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
What is L-tyrosine actually used for?
What side effects should I expect?
Is it safe to take while I'm pregnant or breastfeeding?
Can I take this every day, or just when I need it?
Does this work for brain fog or energy?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Tyrosine 1000 mg is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.
The Full Monographs Behind L-Tyrosine 1000 mg’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
L-Tyrosine 1000 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.
The 4 references behind this product’s interaction data
Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.
Tyrosine 4 references
- Meyer JS, Welch KM, Deshmukh VD, et al. Neurotransmitter precursor amino acids in the treatment of multi-infarct dementia and Alzheimer's disease. J Amer Geriat Soc 1977;25:289-98.
- DiPiro JT, Talbert RL, Yee GC, et al; eds. Pharmacotherapy: A pathophysiologic approach. 4th ed. Stamford, CT: Appleton & Lange, 1999.
- Wood DR, Reimherr FW, Wender PH. Amino acid precursors for the treatment of attention deficit disorder, residual type. Psychopharmacol Bull 1985;21:146-9.
- van Spronsen FJ, van Rijn M, Bekhof J. Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets. Am J Clin Nutr 2001;73:153-7. PubMed
Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC