L-Cysteine Powder Ingredients & Drug Interactions
by Source Naturals
What is this page for?
First and foremost: checking L-Cysteine 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
L-Cysteine Powder is a dietary supplement by Source Naturals 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. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against L-Cysteine Powder by Source Naturals
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Cysteine Powder by Source Naturals — 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-Cysteine 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.
What’s inside
Full disclosure
This powder contains one active ingredient: L-cysteine, an amino acid your body uses to make glutathione, a key antioxidant. There are no inactive ingredients listed for this product.
Does it work?
Couldn't assess
We don't have solid evidence yet for L-cysteine's effectiveness at any of the conditions it's marketed for — androgenic alopecia (male-pattern hair loss), venous leg ulcers (slow-healing sores in the legs), hangover, stroke, and gastritis. The data we hold rates them all as insufficient evidence to say whether it works.
That doesn't mean it doesn't; it means the studies aren't there yet to prove it does.
How safe is it?
Some data gaps
L-Cysteine is generally well tolerated at the amounts found in food, but the long-term safety of high-dose supplements hasn't been well studied. The safety notes advise caution with supplement-level doses unless your doctor recommends otherwise.
Pregnancy and lactation: the data rates L-cysteine as likely safe during pregnancy and breastfeeding, but because high-dose supplement safety overall isn't well established, it's smart to talk with your doctor or pharmacist about whether to take it.
Meds to double-check
Moderate interaction found
Check your exact antidiabetes medications (insulin, metformin, sulfonylureas, and similar drugs) with your doctor or pharmacist before starting L-Cysteine. The interaction is Moderate severity — it may raise the risk of low blood sugar (hypoglycemia).
No other medication types are documented to interact with L-cysteine in our data.
The bottom line
Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Moderate medication interactions have been identified, and some safety-information gaps remain.
L-Cysteine may be worth considering if you're curious about amino acid supplements, but the evidence for what it treats isn't solid yet. If you take any blood sugar medication, you'll need to check with your doctor or pharmacist first — there's a real risk it could lower your blood sugar further.
The long-term safety at supplement doses isn't well known, so stick with personalized advice from your healthcare provider.
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
General information
Key facts about L-Cysteine Powder, straight from the product label.
| Brand | Source Naturals |
|---|---|
| Barcode (UPC) | 021078001201 |
| Net contents | 3.53 Ounce(s); 100 Gram(s) |
| Market status | On market |
| Date entered into DSLD | Nov 22, 2022 |
| DSLD ID | 274767 |
| 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 |
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 Powder by Source Naturals, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Cysteine | 900 mg | -- |
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 Statement of Identity
Dietary Supplement
Formula
L-Cysteine is a crystalline free-form amino acid that is active in many body processes. L-Cysteine works in the liver to protect the body from harmful substances and may help to prevent oxidation of tissues. L-Cysteine, along with L-glutamic acid and glycine, is the rate-limiting precursor in the synthesis of glutathione per-oxidase (one of the body's main antioxidant enzymes), which minimizes lipid peroxidation (fats turning rancid).
Suggested/Recommended/Usage/Directions
Suggested Use: 1/4 teaspoon per day between meals. If you experience stomach irritation, take with meals.
Precautions
Note: If you are pregnant, may become pregnant, or are 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.
Storage
Store in a cool, dry place.
Formulation
Contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.
Free-form
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.
L-Cysteine Powder by Source Naturals 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-Cysteine Powder by Source Naturals
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1.2 Gram(s) Dosage formPowder Servings per container83 Amounts shown are per serving.
L-Cysteine
Interacts with86 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 su...
L-Cysteine monograph & interactionsL-Cysteine Powder by Source Naturals Drug Interactions
HelloPharmacist Interaction Report
Source Naturals L-Cysteine Powder contains one ingredient — L-cysteine — that does interact with a medication type: antidiabetes drugs (such as insulin, metformin, and sulfonylureas).
The concern is Moderate severity: animal research hints that L-cysteine may lower blood sugar (hypoglycemia), so taking it alongside your diabetes medication could theoretically push your blood sugar too low.
Read the full breakdown — every affected drug type, severity by severity
Although this is the only drug type documented to interact with L-cysteine in our data, the risk is real enough that you'll want to check your exact medications with the search tool below before starting this supplement. If you take any antidiabetes drug, talk it over with your doctor or pharmacist first — they may want to monitor your blood sugar more closely or adjust your dose.
Altogether, these interactions span 86 individual medications.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Cysteine 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 checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in L-Cysteine Powder interact with 86 drugs. Click any drug to see the details.
1 of the 1 ingredient in L-Cysteine Powder interact with drugs. Each result below shows which ingredient is responsible. L-Cysteine
AcarboseGlucobay, Prandase, Precose
How Acarbose interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Acarbose interactionAcetohexamideDymelor
How Acetohexamide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Acetohexamide interactionAlbiglutideTanzeum
How Albiglutide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Albiglutide interactionAlogliptinNesina
How Alogliptin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Alogliptin interactionAlogliptin, MetforminKazano
How Alogliptin, Metformin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Alogliptin, Metformin interactionAlogliptin, PioglitazoneOseni
How Alogliptin, Pioglitazone interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Alogliptin, Pioglitazone interactionAntidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) InhibitorGlyxambi
How Antidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) Inhibitor interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Antidiabetes, Dipeptidyl Peptidase-4 (dpp-iv) Inhibitor interactionCanagliflozinInvokana
How Canagliflozin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Canagliflozin interactionCanagliflozin, MetforminInvokamet
How Canagliflozin, Metformin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Canagliflozin, Metformin interactionCanagliflozin, Metformin HydrochlorideInvokamet XR
How Canagliflozin, Metformin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Canagliflozin, Metformin Hydrochloride interactionChlorpropamideChlorpropam, Diabinese
How Chlorpropamide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Chlorpropamide interactionDapagliflozinFarxiga
How Dapagliflozin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dapagliflozin interactionDapagliflozin Propanediol, MetforminXigduo XR
How Dapagliflozin Propanediol, Metformin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dapagliflozin Propanediol, Metformin interactionDapagliflozin Propanediol, Saxagliptin HydrochlorideQtern
How Dapagliflozin Propanediol, Saxagliptin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dapagliflozin Propanediol, Saxagliptin Hydrochloride interactionDapagliflozin, Metformin Hydrochloride, Saxagliptin HydrochlorideQternmet XR
How Dapagliflozin, Metformin Hydrochloride, Saxagliptin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dapagliflozin, Metformin Hydrochloride, Saxagliptin Hydrochloride interactionDasiglucagon HydrochlorideZegalogue
How Dasiglucagon Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dasiglucagon Hydrochloride interactionDulaglutideTrulicity
How Dulaglutide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Dulaglutide interactionEmpagliflozinJardiance
How Empagliflozin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Empagliflozin interactionEmpagliflozin, Linagliptin, Metformin HydrochlorideTrijardy XR
How Empagliflozin, Linagliptin, Metformin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Empagliflozin, Linagliptin, Metformin Hydrochloride interactionEmpagliflozin, MetforminSynjardy
How Empagliflozin, Metformin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Empagliflozin, Metformin interactionEmpagliflozin, Metformin HydrochlorideSynjardy XR
How Empagliflozin, Metformin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Empagliflozin, Metformin Hydrochloride interactionErtugliflozinSteglatro
How Ertugliflozin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Ertugliflozin interactionErtugliflozin, Metformin HydrochlorideSegluromet
How Ertugliflozin, Metformin Hydrochloride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Ertugliflozin, Metformin Hydrochloride interactionExenatideBydureon, Byetta
How Exenatide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Exenatide interactionExenatide SyntheticBydureon BCISE
How Exenatide Synthetic interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Exenatide Synthetic interactionGliclazideDiamicron
How Gliclazide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Gliclazide interactionGlimepirideAmaryl
How Glimepiride interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Glimepiride interactionGlipizideGlucotrol, Glucotrol XL
How Glipizide interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Glipizide interactionGlipizide, MetforminMetaglip
How Glipizide, Metformin interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Glipizide, Metformin interactionGlucagonBaqsimi, Glucagon
How Glucagon interacts with L-Cysteine Powder — through 1 ingredient. Tap an ingredient for the detail:
L-cysteineAntidiabetes Drugs Moderate
Interaction Summary
Theoretically, taking L-cysteine supplements with antidiabetes drugs might increase the risk of hypoglycemia.
Read the full L-cysteine + Glucagon interactionEach ingredient & the kinds of drugs it affects
For each ingredient in L-Cysteine 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-Cysteine
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.
Brand information
Manufacturer and brand details for L-Cysteine 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
L-Cysteine Powder by Source Naturals: Common Questions
Does L-Cysteine Powder by Source Naturals interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Is L-Cysteine safe to take while pregnant or breastfeeding?
Does L-Cysteine actually help with hair loss?
What does L-cysteine do in the body?
Are there any side effects listed for L-Cysteine?
Can I take L-Cysteine if I take diabetes medication?
How long has L-Cysteine been studied?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Cysteine Powder 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-Cysteine Powder’s Ingredients
Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.
Sources & How We Checked
L-Cysteine 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.
- 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 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
- 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.
- 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.
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