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Dietary supplement

L-Cysteine 500 mg Ingredients & Drug Interactions

by Solgar

L-Cysteine 500 mg label
See full label image
Capsule 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-Cysteine 500 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

The interaction bottom line Most serious interaction: Moderate

L-Cysteine 500 mg is a dietary supplement by Solgar with 1 active ingredient. Its ingredients are commonly taken for antioxidant support, skin and hair health, liver support.Based on those ingredients, 86 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Cysteine Hydrochloride. 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-Cysteine 500 mg by Solgar

Ask about any prescription or over-the-counter medication and we check it for interactions with L-Cysteine 500 mg by Solgar — and tell you which ingredient is responsible.

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Computed from our clinical databases

HelloPharmacist Scorecard of L-Cysteine 500 mg by Solgar

Four independent checks of what is known — a summary of the available information, not a grade of the product itself.

Evidence for Intended Use
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
Not assessable

The stated purpose hasn't been mapped to our evidence data yet.

Why this rating?
  • We haven't mapped this product's purpose to our evidence data yet — it'll be graded on the next content refresh.
Ingredient Transparency
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.
Known Interaction Concern
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 — L-cysteine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: diabetes medications.
  • For scale: 86 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.
Safety Information
Some gaps

Safety data exists for these ingredients, but with some important gaps.

Why this rating?
  • We hold adverse-effect (side-effect) data for 0 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.

HelloPharmacist summaryFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and some safety-information gaps remain.

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Apr 23, 2020.

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-Cysteine 500 mg, straight from the product label.

Brand Solgar
Barcode (UPC) 033984009615
Net contents 60 Vegetable Capsule(s)
Market status On market
Date entered into DSLD Apr 23, 2020
DSLD ID 217644
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Kosher, 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-Cysteine 500 mg by Solgar, 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:
1 Vegetarian Capsule(s)
Maximum serving Sizes:
1 Vegetarian Capsule(s)
UPC/BARCODE
033984009615
IngredientAmount% DV
L-Cysteine Hydrochloride500 mg--

Other ingredients: Vegetable Cellulose, Vegetable Magnesium Stearate, Silica, Microcrystalline Cellulose

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.
Formula

L-Cysteine is a sulfur-containing amino acid that helps synthesize keratin, a protein found in skin, hair and nails. It is also a precursor to L-Glutathione, a tripeptide involved in one of the body's detoxification systems. This product provides free form L-Cysteine to promote optimal absorption and assimilation.

Solgar's KOF-K certification #K-1250

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)

2014 Solgar, Inc.

General Statements

Solgar since 1947

Formulation

Free form

Gluten, wheat & dairy free

Suitable for vegetarians

Free of: Gluten, wheat, dairy, soy, yeast, sugar, sodium, artificial flavor, sweetener, preservatives and color.

Seals/Symbols

K Parve (Kosher)

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement for adults, take one (1) vegetable capsule twice daily, between meals or as directed by a healthcare practitioner.

Precautions

If you are pregnant, nursing, taking any medication or have a medical condition, please consult your healthcare practitioner before taking any dietary supplement.

Discontinue use and consult your healthcare practitioner if any adverse reactions occur.

Keep out of reach of children.

Do not use if outer bottle seal is missing or damaged.

Storage

Store at room temperature.

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

See for yourself

L-Cysteine 500 mg by Solgar label

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

L-Cysteine 500 mg 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-Cysteine 500 mg by Solgar

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

Serving size1 Vegetarian Capsule(s) Dosage formCapsule Amounts shown are per serving.

L-Cysteine Hydrochloride

Interacts with
86 drugs
500 mg per serving

L-cysteine is a sulfur-containing amino acid your body uses to make proteins and the antioxidant glutathione. Most people get enough from food, and su...

L-Cysteine Hydrochloride monograph & interactions

Other (inactive) ingredients: Vegetable Cellulose, Vegetable Magnesium Stearate, Silica, Microcrystalline Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Cysteine 500 mg by Solgar Drug Interactions

L-Cysteine 500 mg contains a single active ingredient, and it has known interactions with 86 medications. Here’s the picture, then you can look up your own drug.

Want to check YOUR meds against L-Cysteine 500 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 checker
86Drugs
86 Moderate

Ingredients driving the most interactions

L-Cysteine Hydrochloride 86

Individual Drug Interactions

The ingredients in L-Cysteine 500 mg interact with 86 drugs. Click any drug to see the details.

1 of the 1 ingredient in L-Cysteine 500 mg interact with drugs. Each result below shows which ingredient is responsible. L-Cysteine Hydrochloride

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Cysteine 500 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-Cysteine Hydrochloride1 drug type · 86 drugs

Antidiabetes Drugs

Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Animal research suggests that L-cysteine can have hypoglycemic effects.

Likelihood Possible Evidence D
L-Cysteine Hydrochloride full monograph & interactions
The maker

Brand information

Manufacturer and brand details for L-Cysteine 500 mg, from the product label.

Solgar

See all Solgar products
Name
Solgar, Inc.
Street Address
500 Willow Tree Road
City
Leonia
State
NJ
ZipCode
07605
Phone Number
1-877-765-4274
Web Address
www.solgar.com
Pharmacist Counseling Corner

L-Cysteine 500 mg by Solgar: Common Questions

Does L-Cysteine 500 mg by Solgar interact with any medications?
Yes. Based on its ingredients, L-Cysteine 500 mg has a known interaction with 86 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Cysteine 500 mg 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.

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

Not sure if L-Cysteine 500 mg is safe with your meds?

Our pharmacists answer your medication & supplement questions — free.

Ask a pharmacist

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-Cysteine 500 mg label
Go deeper

The Full Monographs Behind L-Cysteine 500 mg’s Ingredients

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

Herb & supplement monograph

L-cysteine

Interacts with 86 drugs

L-cysteine is a sulfur-containing amino acid your body uses to make proteins and the antioxidant glutathione. Most people get enough from food, and supplements are usually well tolerated, bu...

Read the full L-cysteine monograph →
Sources

Sources & How We Checked

L-Cysteine 500 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.

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 2 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.

L-cysteine 2 references
  1. Dowlati Y, Maheux M, Meyer JH. The effect of oral L-cysteine on breast milk and plasma cysteine concentrations. Neuropsychiatr Dis Treat 2020;16:3163-3172.
  2. Lee S, Han KH, Nakamura Y, et al. Dietary L-cysteine improves the antioxidative potential and lipid metabolism in rats fed a normal diet. Biosci Biotechnol Biochem 2013;77(7):1430-4.

See these in context on the L-cysteine 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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