Ultimate Respiratory Defense by Swanson — Ingredients, Evidence & Safety

🟢 100/100

This product looks safe

No ingredients exceed tolerable upper intake levels
100% of ingredients have research evidence

A Label Compliance Grade

Product Label

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Label Data

1 Veggie Capsule(s) Serving Size

60 Servings

Non-Nutrient/Non-Botanical Product Type

100% Evidence Coverage

Supplement Facts — Evidence Check

N-Acetyl Cysteine

600 mg

📊 Market median: 600.0mg (7 products) 📚 39 studies (Tier A: 2, B: 13)

This product: 600mg

Quercetin

300 mg

📊 Market median: 500.0mg (283 products) 📚 173 studies (Tier A: 0, B: 62)

This product: 300mg

Other Ingredients

Hypromellose Rice Bran Magnesium Stearate Silica

Label Claims — Verification

❓ All Other

❓ Structure/Function

All Other (96% of products) Structure/Function (81% of products) Nutrient (19% of products) No Claim (3% of products)

Target Groups

Vegetarian Adult (18 - 50 Years) Women (not pregnant or lactating)

Product Information

📋 Directions for Use

Suggested use: as a dietary supplement, take one veggie capsule per day with water or as recommended by your healthcare provider.

⚠️ Warnings & Precautions

Warning: for adults only. Keep out of reach of children.

Do not take this product if you are pregnant or nursing. Consult your healthcare provider before use if you are taking any prescription medication or if you have a medical condition.

Discontinue use if you experience gastrointestinal discomfort. Do not use if seal is broken.

🧪 Formulation Notes

Supports healthy respiratory function and cellular antioxidant activity Science-backed quality since 1969

NAC helps replenish glutathione, a critical component of the body's defense system

V Vegetarian

Ultimate Respiratory Defense with NAC and Quercetin

Respiratory health Advanced formula

Additional Information

Swanson.com or call 1-800-437-4148

V Vegetarian

Store in a cool, dry place.

Product Details

UPC / SKU 0 87614 11852 9

DSLD Entry Date 2025-02-23

Product Type Non-Nutrient/Non-Botanical

Form Capsule

Brand Swanson

DSLD ID 322784

Data Updated 2026-04-11

Research Evidence

41 Research Sources

51 Avg Quality Score

19 Rct

13 Meta Analysis

9 Clinical Trial

B N-acetylcysteine as an adjuvant therapy for Helicobacter pylori eradication

Meta Analysis The Cochrane database of systematic reviews 2019

PubMed DOI

B Effect of high-dose N-acetylcysteine on exacerbations and lung function in patients with mild-to-moderate COPD: a double-blind, parallel group, multicentre randomised clinical trial

Rct Nature communications 2024

PubMed DOI

B N-acetylcysteine for non-paracetamol (acetaminophen)-related acute liver failure

Meta Analysis The Cochrane database of systematic reviews 2020

PubMed DOI

B Influence of N-acetylcysteine on chronic bronchitis or COPD exacerbations: a meta-analysis

Meta Analysis European respiratory review : an official journal of the European Respiratory Society 2015

PubMed DOI

B A randomised controlled trial of a mitochondrial therapeutic target for bipolar depression: mitochondrial agents, N-acetylcysteine, and placebo

Rct BMC medicine 2019

PubMed DOI

B Efficacy of N-acetylcysteine for patients with depression: An updated systematic review and meta-analysis

Meta Analysis General hospital psychiatry 2024

PubMed DOI

B Cysteine, cystine or N-acetylcysteine supplementation in parenterally fed neonates

Meta Analysis The Cochrane database of systematic reviews 2006

PubMed

B N-acetylcysteine as an adjunctive treatment for bipolar depression: A systematic review and meta-analysis of randomized controlled trials

Meta Analysis Bipolar disorders 2021

PubMed DOI

B N-acetylcysteine as an adjunctive treatment for bipolar depression and major depressive disorder: a systematic review and meta-analysis of double-blind, randomized placebo-controlled trials

Meta Analysis Psychopharmacology 2020

PubMed DOI

B N-acetylcysteine Treatment in Chronic Obstructive Pulmonary Disease (COPD) and Chronic Bronchitis/Pre-COPD: Distinct Meta-analyses

Meta Analysis Archivos de bronconeumologia 2024

PubMed DOI

View all evidence for Nac →