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Dietary supplement

100% Pure L-Cysteine Ingredients & Drug Interactions

by NutraBio

100% Pure L-Cysteine 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 100% Pure L-Cysteine 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

100% Pure L-Cysteine is a dietary supplement by NutraBio 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 100% Pure L-Cysteine by NutraBio

Ask about any prescription or over-the-counter medication and we check it for interactions with 100% Pure L-Cysteine by NutraBio — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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Computed from our clinical databases

HelloPharmacist Scorecard of 100% Pure L-Cysteine by NutraBio

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 Oct 22, 2015.

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 100% Pure L-Cysteine, straight from the product label.

Brand NutraBio
Barcode (UPC) 649908242619
Net contents 1.1 lbs; 500 Gram(s)
Market status On market
Date entered into DSLD Oct 22, 2015
DSLD ID 51130
Product type Amino Acid/protein
Supplement form Powder
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher, No Allergies, Gluten 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 100% Pure L-Cysteine by NutraBio, 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 Gram(s)
Maximum serving Sizes:
1 Gram(s)
Servings per container
500
UPC/BARCODE
649908242619
IngredientAmount% DV
L-Cysteine Hydrochloride1000 mg--

Other ingredients: Absolutely None

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.
Suggested/Recommended/Usage/Directions

1 serving Mixed with 8-16 oz. Favorite beverage 1-2x daily with food Suggested Use: As a dietary supplement, take 1 serving with your favorite beverage up to 2 times daily between meals, or as directed by your physician. If you experience stomach irritation, take with meals.

Precautions

Warning: Not intended for use by persons under the age of 18. Keep out of the reach of children.

If you are pregnant, breast feeding, have known medical conditions (including kidney or liver disease) or are taking prescription or OTC medication(s) consult with your health care practitioner before using this product.

General Statements

Manufactured in a GMP & FDA inspected facility

Powder 500 Servings

Made in a GMP & FDA inspected facility

Serving scoop included (may settle to the bottom during shipping.)

Quality & purity since 1996. Nutrabio manufactures in our own FDA registered & inspected. GMP facility complying with FDA 21 CFR Part 111 regulations.

Formulation

Kosher, Hypoallergenic, Non-GMO, Gluten free & BSE/TSE free. No added sugars, salt, preservatives, salicylates, or artificial color, flavor or fragrance.

Allergen Free ~ Non-GMO ~ Gluten Free ~ BSE/TSE Free

No Fillers ~ No Exipients ~ No Additives

Zero fillers or exipients inferior ingredients banned substances added sugars proprietary blends hidden ingredients

Brand IP Statement(s)

Amino Therapy

Formula

Pharmaceutical Free Form Amino Acid

Kosher, Hypoallergenic, Non-GMO, Gluten free & BSE/TSE free.

Kosher, Hypoallergenic, Non-GMO, Gluten free & BSE/TSE free.

Seals/Symbols

TRUE LABEL FULL LABEL DISCLSOURE

OU

Since 1996

FDA Statement of Identity

Dietary Supplement

Storage

Store in a cool dry place.

General

24261-005 B20260-001

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.

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

See for yourself

100% Pure L-Cysteine by NutraBio label

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

100% Pure L-Cysteine 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 100% Pure L-Cysteine by NutraBio

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

Serving size1 Gram(s) Dosage formPowder Servings per container500 Amounts shown are per serving.

L-Cysteine Hydrochloride

Interacts with
86 drugs
1000 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: Absolutely None. These complete the product’s ingredient list but are not active constituents.

Interaction report

100% Pure L-Cysteine by NutraBio Drug Interactions

100% Pure L-Cysteine 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 100% Pure L-Cysteine?

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 100% Pure L-Cysteine interact with 86 drugs. Click any drug to see the details.

1 of the 1 ingredient in 100% Pure L-Cysteine 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 100% Pure L-Cysteine 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 100% Pure L-Cysteine, from the product label.

NutraBio

See all NutraBio products
Name
NutraBio Labs, Inc.
Street Address
564 Lincoln Blvd.
City
Middlesex
State
NJ
ZipCode
08846
Phone Number
732-748-8606
Web Address
www.nutrabio.com
Pharmacist Counseling Corner

100% Pure L-Cysteine by NutraBio: Common Questions

Does 100% Pure L-Cysteine by NutraBio interact with any medications?
Yes. Based on its ingredients, 100% Pure L-Cysteine 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?
100% Pure L-Cysteine 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 100% Pure L-Cysteine 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.

100% Pure L-Cysteine label
Go deeper

The Full Monographs Behind 100% Pure L-Cysteine’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

100% Pure L-Cysteine'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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