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Dietary supplement

L-Tyrosine Powder Ingredients & Drug Interactions

by Source Naturals

L-Tyrosine Powder label
See full label image
Powder Category: Amino Acid/protein
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking L-Tyrosine Powder 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

The interaction bottom line Most serious interaction: Moderate

L-Tyrosine Powder is a dietary supplement by Source Naturals 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.

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Check Your Meds Against L-Tyrosine Powder by Source Naturals

Ask about any prescription or over-the-counter medication and we check it for interactions with L-Tyrosine Powder by Source Naturals — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of L-Tyrosine Powder by Source Naturals

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.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Aug 13, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: L-tyrosine, an amino acid your body uses to make neurotransmitters (brain signaling chemicals) and thyroid hormones. There are no inactive ingredients in this powder formula.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: mental focus, alertness, stress, and mood support.
  • We looked for evidence on: Attention deficit-hyperactivity disorder (ADHD), Cognitive function, Depression, Fatigue, Memory, Stress — and 2 related terms.
  • The strongest evidence on file: Tyrosine is rated "Possibly Effective" for Cognitive function (Natural Medicines).
  • Also on file: Tyrosine is rated "Possibly Effective" for Memory.
  • Also on file: Tyrosine is rated "Insufficient Reliable Evidence To Rate" for Attention deficit-hyperactivity disorder (ADHD), Depression, Fatigue, Stress.

L-tyrosine is effective for phenylketonuria (PKU), a rare metabolic condition. It's possibly effective for cognitive function and memory, meaning the evidence suggests benefit but isn't conclusive.

The data we hold rates it possibly ineffective for athletic performance. Evidence isn't established for alcohol use disorder or dementia.

The evidence, ingredient by ingredient Tyrosine

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-tyrosine is generally well tolerated in healthy adults, but talk with your healthcare provider before regular use. The most common side effects are fatigue, headache, heartburn, and nausea.

Higher doses may increase the risk of headache and fatigue; these effects usually improve when you lower the dose. There isn't enough safety data to know whether it's safe during pregnancy or breastfeeding—talk with your doctor or pharmacist for personalized advice.

Side effects, ingredient by ingredient Tyrosine

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Tyrosine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: Parkinson's medications.
  • For scale: 21 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking this product, check with your pharmacist or doctor if you take levodopa (a Parkinson's medication) or thyroid hormone replacement. Both interactions are Moderate severity and may affect how well your medications work.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

L-tyrosine may help with memory and thinking if the evidence holds up for you, but it's not proven for athletic performance. If you take levodopa or thyroid medication, check with your pharmacist or doctor before starting.

It's generally well tolerated, though fatigue and headache can happen, especially at higher doses.

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 Nov 22, 2022.

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

At a glance

General information

Key facts about L-Tyrosine Powder, straight from the product label.

Brand Source Naturals
Barcode (UPC) 021078001874
Net contents 3.53 Ounce(s); 100 Gram(s)
Market status On market
Date entered into DSLD Nov 22, 2022
DSLD ID 274814
Product type Amino Acid/protein
Supplement form Powder
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar Free
From the label
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 Powder by Source Naturals, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
0.67 Gram(s)
Maximum serving Sizes:
0.67 Gram(s)
Servings per container
149
UPC/BARCODE
021078001874
IngredientAmount% DV
L-Tyrosine660 mg--

Tap any ingredient to jump to its full detail below.

Label statements
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 Statement of Identity

Amino Acid Supplement

Formulation

Free-form powder

Contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.

Formula

L-Tyrosine is a free-form amino acid which crosses the blood-brain barrier. It is a precursor for the neurotransmitters dopamine, norepinephrine, and epinephrine, as well as for thyroid hormones and enkephalins, important peptides which ease messages of physical discomfort. L-Tyrosine is also a constituent of amino sugars (glycosaminoglycans), which play a role in numerous biological functions.

Suggested/Recommended/Usage/Directions

Suggested Use: 1/4 teaspoon daily, mixed with water or juice between meals.

Precautions

Not to be used with MAO inhibitor drugs. If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.

Do not use if either tamper-evident seal is broken or missing.

Keep out of the reach of children.

Warning: Contains tyrosine.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

Brand IP Statement(s)

Copyright SOURCE NATURALS, INC.

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

L-Tyrosine Powder by Source Naturals label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

L-Tyrosine Powder label

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)
What’s inside

The Ingredients in L-Tyrosine Powder by Source Naturals

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size0.67 Gram(s) Dosage formPowder Servings per container149 Amounts shown are per serving.

L-Tyrosine

Interacts with
21 drugs
660 mg per serving

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 & interactions
Interaction report

L-Tyrosine Powder by Source Naturals Drug Interactions

Want to check YOUR meds against L-Tyrosine Powder?

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 checker
21Drugs
21 Moderate

Ingredients driving the most interactions

L-Tyrosine 21

Individual Drug Interactions

The ingredients in L-Tyrosine Powder interact with 21 drugs. Click any drug to see the details.

1 of the 1 ingredient in L-Tyrosine Powder interact with drugs. Each result below shows which ingredient is responsible. L-Tyrosine

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Tyrosine Powder 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-Tyrosine2 drug types · 21 drugs

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.

Likelihood Probable Evidence D
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.

Likelihood Probable Evidence D
L-Tyrosine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for L-Tyrosine Powder, from the product label.

Source Naturals

Name
Source Naturals, Inc.
Street Address
P. O. Box 2118
City
Santa Cruz
State
CA
ZipCode
95062
Web Address
www.sourcenaturals.com
Pharmacist Counseling Corner

L-Tyrosine Powder by Source Naturals: Common Questions

Does L-Tyrosine Powder by Source Naturals interact with any medications?
Yes. Based on its ingredients, L-Tyrosine Powder has a known interaction with 21 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Tyrosine Powder contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
What does L-tyrosine actually do?
L-tyrosine is an amino acid your body uses to make neurotransmitters and thyroid hormones. It may help with memory and thinking, and it's proven helpful for a rare metabolic condition called PKU.
Is this safe to take while pregnant or breastfeeding?
There isn't enough safety data to know either way. Talk with your doctor or pharmacist before taking this supplement while pregnant or nursing—they can weigh the pros and cons for your situation.
What side effects might I get?
Most people tolerate it well. The most common side effects are fatigue, headache, heartburn, and nausea. Higher doses are more likely to cause headache and fatigue, but lowering the dose usually helps.
Can I take this with my Parkinson's medication?
You can, but you need to separate your doses. Tyrosine and levodopa compete for absorption, so space them at least 2 hours apart. Talk with your pharmacist about the best timing for your routine.
Does this work for athletic performance?
The data we hold rates it possibly ineffective for athletic performance, so it's not a solid choice for that goal.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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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.

L-Tyrosine Powder label
Go deeper

The Full Monographs Behind L-Tyrosine Powder’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Tyrosine

Interacts with 21 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 performance during short-term stress, sleep loss,...

Read the full Tyrosine monograph →
Sources

Sources & How We Checked

L-Tyrosine Powder'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.

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
  1. 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.
  2. DiPiro JT, Talbert RL, Yee GC, et al; eds. Pharmacotherapy: A pathophysiologic approach. 4th ed. Stamford, CT: Appleton & Lange, 1999.
  3. Wood DR, Reimherr FW, Wender PH. Amino acid precursors for the treatment of attention deficit disorder, residual type. Psychopharmacol Bull 1985;21:146-9.
  4. van Spronsen FJ, van Rijn M, Bekhof J. Phenylketonuria: tyrosine supplementation in phenylalanine-restricted diets. Am J Clin Nutr 2001;73:153-7. PubMed

See these in context on the Tyrosine monograph →

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

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