Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Winter Wellness Ingredients & Drug Interactions

by Life Extension

Winter Wellness label
See full label image
Capsule Category: Other Combinations
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 Winter Wellness 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

Winter Wellness is a dietary supplement by Life Extension with 2 active ingredients. Its ingredients are commonly taken for anxiety and stress, relaxation and calm, sleep support.Based on those ingredients, 651 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are L-Theanine, L-Cysteine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Winter Wellness by Life Extension

Ask about any prescription or over-the-counter medication and we check it for interactions with Winter Wellness by Life Extension — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Winter Wellness by Life Extension

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 Jul 11, 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 2 of its 2 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

Winter Wellness contains 2 active ingredients: L-theanine and L-cysteine. L-theanine is an amino acid that some research suggests may help with cognitive function and mental focus.

L-cysteine is another amino acid that your body uses to make glutathione, an important antioxidant. The capsule also contains several inactive ingredients (vegetable cellulose, dicalcium phosphate, microcrystalline cellulose, silica, and vegetable stearate) that help hold the formula together.

Does it work?

Not established
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
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use.

Why this rating?
  • The label markets this product for: Enhances and balances immune response.
  • We looked for evidence on: Influenza, Immune function, Respiratory health, Antiviral support.
  • The closest evidence on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Influenza (Natural Medicines).

The evidence for what these ingredients do is mixed and limited. L-theanine is possibly effective for cognitive function, but we don't have enough reliable evidence to rate it for age-related cognitive decline, Alzheimer disease, anxiety disorders, or cancer.

L-cysteine hasn't been rated for any of the conditions listed — the data shows insufficient evidence for androgenic alopecia, venous leg ulcers, hangover, stroke, and gastritis. In short, while these ingredients are studied, we can't confidently say they work for most of the reasons people might take them.

The evidence, ingredient by ingredient Theanine L-cysteine

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 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-theanine is generally well tolerated in the short term for healthy adults, but long-term safety hasn't been well studied. Reported side effects include headaches, drowsiness, increased sleep duration, and increased dream activity.

L-cysteine is generally well tolerated at food amounts, but the safety of high-dose supplements over longer periods isn't well established, so use caution. For pregnancy: L-theanine doesn't have enough safety data — the facts advise against it during pregnancy and breastfeeding.

L-cysteine is rated likely safe at normal food doses, but supplement-level doses aren't well studied, so talk with your doctor or pharmacist before using it if you're pregnant or breastfeeding.

Side effects, ingredient by ingredient Theanine L-cysteine

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?
  • 2 of the 2 matched ingredients can interact with medications — Theanine, L-cysteine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: diabetes medications.
  • For scale: 651 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 Winter Wellness, double-check with your pharmacist if you take antihypertensive drugs (blood pressure medications) — L-theanine may lower your blood pressure further. If you're on antidiabetes medications (insulin, metformin, or others), L-cysteine might lower your blood sugar.

CNS depressants (sleep aids, sedatives) and serotonergic drugs (certain antidepressants) may also warrant a quick check, though those interactions are minor or uncertain.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

Winter Wellness is worth considering if you're interested in supporting cognitive function and antioxidant defense, but the evidence for most uses is still limited. If you take blood pressure medications, diabetes medications, or any sedating drugs, you'll want to check this product against your exact medications first — the interactions are real.

Talk to your pharmacist before starting, especially if you're pregnant, breastfeeding, or on any regular prescriptions.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 2 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Apr 22, 2016.

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 Winter Wellness, straight from the product label.

Brand Life Extension
Barcode (UPC) 737870173960
Net contents 60 Capsule(s)
Market status On market
Date entered into DSLD Apr 22, 2016
DSLD ID 59062
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Winter Wellness by Life Extension, 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:
2 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
30
UPC/BARCODE
737870173960
IngredientAmount% DV
L-Theanine280 mg--
L-Cysteine700 mg--

Other ingredients: Vegetable Cellulose, Dicalcium Phosphate, Microcrystalline Cellulose, Silica, Vegetable Stearate

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

Scan for product info

Enhances and Balances Immune Response*

To report a serious adverse event or obtain product information, contact 1-866-280-2852.

Suggested/Recommended/Usage/Directions

Read the entire label and follow the directions carefully prior to use. DIRECTIONS: Take two (2) capsules daily with or without food, or as recommended by a healthcare practitioner.

Storage

Store tightly closed in a cool, dry place.

Precautions

WARNINGS: ~ KEEP OUT OF REACH OF CHILDREN.

~ DO NOT EXCEED RECOMMENDED DOSE. ~ Do not purchase if outer seal is broken or damaged.

~ When using nutritional supplements, please consult with your physician if you are undergoing treatment for a medical condition or if you are pregnant or lactating.

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.

FDA Statement of Identity

Dietary Supplement

General

Q01739B

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

See for yourself

Winter Wellness by Life Extension label

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

Winter Wellness 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 Winter Wellness by Life Extension

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

L-Theanine

Interacts with
565 drugs
280 mg per serving

Theanine (usually L-theanine) is an amino acid found naturally in tea leaves that many people take to feel calmer and less stressed without strong dro...

L-Theanine monograph & interactions

L-Cysteine

Interacts with
86 drugs
700 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 monograph & interactions

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

Interaction report

Winter Wellness by Life Extension Drug Interactions

Want to check YOUR meds against Winter Wellness?

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
651Drugs
258 Moderate 393 Minor

Ingredients driving the most interactions

L-Theanine 565
L-Cysteine 86

Individual Drug Interactions

The ingredients in Winter Wellness interact with 651 drugs. Click any drug to see the details.

2 of the 2 ingredients in Winter Wellness interact with drugs. Each result below shows which ingredient is responsible. L-Theanine L-Cysteine

Each ingredient & the kinds of drugs it affects

For each ingredient in Winter Wellness with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

L-Theanine3 drug types · 565 drugs

Antihypertensive Drugs

Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Animal research shows that theanine can lower blood pressure in spontaneously hypertensive animals. Theoretically, concomitant use of theanine and antihypertensive drugs might potentiate the antihypertensive activity.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, theanine might have additive sedative effects when used in conjunction with CNS depressants. However, it is unclear if this concern is clinically relevant.
Theoretically, theanine may compete with glutamate and/or increase plasma gamma-aminobutyric acid (GABA) levels, which could cause CNS depression. In one clinical study, some subjects taking oral theanine reported drowsiness.

Likelihood Unlikely Evidence D
Serotonergic Drugs

Clinical studies regarding the effects of L-theanine on serotonin levels are conflicting. Some studies suggest it can increase serotonin levels in the brain while others report that it may decrease them. Nevertheless, there have been no reports of l-theanine being a causative agent in serotonergic-related side effects or serotonin syndrome.

Likelihood Unlikely Evidence C
L-Theanine full monograph & interactions

L-Cysteine1 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 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Winter Wellness, from the product label.

Life Extension

See all Life Extension products
Name
Quality Supplements and Vitamins, Inc.
City
Ft. Lauderdale
State
Florida
ZipCode
33309
Phone Number
1-866-280-2852
Web Address
www.lef.org
Pharmacist Counseling Corner

Winter Wellness by Life Extension: Common Questions

Does Winter Wellness by Life Extension interact with any medications?
Yes. Based on its ingredients, Winter Wellness has a known interaction with 651 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Winter Wellness contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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.
Can I take Winter Wellness if I'm pregnant or breastfeeding?
L-theanine doesn't have enough safety data — the facts advise against it during pregnancy and breastfeeding. L-cysteine is rated likely safe at food amounts, but supplement doses aren't well studied. Talk with your doctor or pharmacist before taking this product if you're pregnant or breastfeeding, since it contains both ingredients.
What side effects might I experience?
L-theanine may cause headaches, drowsiness, increased sleep duration, or more vivid dreams. L-cysteine has no reported adverse effects listed in our data. Most people tolerate both ingredients well, but stop and talk to your pharmacist if anything unusual happens.
How long can I safely take this product?
L-theanine is generally well tolerated in the short term, but long-term safety hasn't been studied. L-cysteine is fine at food amounts, but the safety of supplement-level doses over time isn't well established. If you plan to take it regularly, ask your pharmacist how long is reasonable for you.
Does this product actually work for cognitive function?
L-theanine is possibly effective for cognitive function, which means some evidence supports it, but the results aren't definitive. L-cysteine hasn't been rated for cognitive function — the evidence for most of its proposed uses is insufficient. Results vary between people, and more research is needed.
What are L-theanine and L-cysteine?
Both are amino acids — building blocks your body uses for various functions. L-theanine is found in tea and may support focus and calm. L-cysteine helps your body make glutathione, a major antioxidant that protects cells.
Does this product have any fillers or inactive ingredients?
Yes, the capsule contains vegetable cellulose, dicalcium phosphate, microcrystalline cellulose, silica, and vegetable stearate. These help formulate and protect the active ingredients — they're standard in supplements.

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

Not sure if Winter Wellness is safe with your meds?

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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.

Winter Wellness label
Go deeper

The Full Monographs Behind Winter Wellness’s Ingredients

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

Herb & supplement monograph

Theanine

Interacts with 565 drugs

Theanine (usually L-theanine) is an amino acid found naturally in tea leaves that many people take to feel calmer and less stressed without strong drowsiness. Early research suggests it may...

Read the full Theanine monograph → 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

Winter Wellness'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 8 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.

Theanine 6 references
  1. Yokogoshi H, Kobayashi M. Hypotensive effect of gamma-glutamylethylamide in spontaneously hypertensive rats. Life Sci 1998;62:1065-8.
  2. Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., and Scholey, A. B. The effects of L-theanine, caffeine and their combination on cognition and mood. Biol.Psychol. 2008;77(2):113-122. PubMed
  3. Yokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., and Takeuchi, N. Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Biosci.Biotechnol.Biochem. 1995;59(4):615-618. PubMed
  4. Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011;16(4):348-
  5. Hidese S, Ota M, Wakabayashi C, et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr 2017;29(2):72-9.
  6. Tsuchiya T, Honda H, Oikawa M, et al. Oral administration of the amino acids cystine and theanine attenuates the adverse events of S-1 adjuvant chemotherapy in gastrointestinal cancer patients. Int J Clin Oncol 2016;21(6):1085-90. PubMed

See these in context on the Theanine monograph →

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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