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Dietary supplement

L-Cysteine-S Ingredients & Drug Interactions

by Nutri-West

L-Cysteine-S label
See full label image
Tablet Or Pill 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-S 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-S is a dietary supplement by Nutri-West 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-S by Nutri-West

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

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Computed from our clinical databases

HelloPharmacist Scorecard of L-Cysteine-S by Nutri-West

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 Nov 25, 2013.

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-S, straight from the product label.

Brand Nutri-West
Net contents 60 Tablet(s); 500 mg
Market status On market
Date entered into DSLD Nov 25, 2013
DSLD ID 28009
Product type Amino Acid/protein
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), 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-S by Nutri-West, 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 Tablet(s)
Maximum serving Sizes:
1 Tablet(s)
IngredientAmount% DV
L-Cysteine Hydrochloride500 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.
General Statements

0493 MFG04/2010

FOR DISTRIBUTION BY HEALTH CARE PROFESSIONALS ONLY.

Manufactured under strict GMP and USP guidelines.

"When You Want The Best"

Suggested/Recommended/Usage/Directions

Directions for use: One tablet daily or as directed.

Formulation

Contains no starch, salt, sugar, wheat, corn, yeast, soy, milk, or preservatives.

Storage

Store in cool, dry place.

Precautions

KEEP OUT OF REACH OF CHILDREN.

TAMPER RESISTANT OUTER SEAL - DO NOT USE IF BROKEN.

FDA Statement of Identity

Dietary Supplement

General

Product # 1912

Is this label outdated?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

See for yourself

L-Cysteine-S by Nutri-West label

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

L-Cysteine-S 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-S by Nutri-West

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

Serving size1 Tablet(s) Dosage formTablet Or Pill 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
Interaction report

L-Cysteine-S by Nutri-West Drug Interactions

L-Cysteine-S 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-S?

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-S interact with 86 drugs. Click any drug to see the details.

1 of the 1 ingredient in L-Cysteine-S 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-S 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-S, from the product label.

Nutri-West

See all Nutri-West products
Name
Nutri-West
City
Douglas
State
Wy
ZipCode
82633
Pharmacist Counseling Corner

L-Cysteine-S by Nutri-West: Common Questions

Does L-Cysteine-S by Nutri-West interact with any medications?
Yes. Based on its ingredients, L-Cysteine-S 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-S 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-S is safe with your meds?

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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-S label
Go deeper

The Full Monographs Behind L-Cysteine-S’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-S'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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