Common Cold

Why it works: Vitamin C is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement. Vitamin C is required for the biosynthesis of...

Instructions: For Prevention (Regular Supplementation): In adults the duration of colds was reduced by 8% (3% to 12%) and in children by 14% (7% to 21%). In children, 1 to 2 g/day vitamin C shor...

Warnings: Safety Upper Limits: The FNB has established ULs for vitamin C that apply to both food and supplemen...

Studies: Major Cochrane Review (Gold Standard): Twenty-nine trial com...

Why it works: Zinc's effectiveness against the common cold appears to work through two main mechanisms: suppression of nasal inflammation and direct inhibition of rhinoviral receptor binding and...

Instructions: Timing and Dosage:. Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onse...

Warnings: FDA Warnings on Nasal Zinc Products:. In June 2009, the United States Food and Drug Administration w...

Studies: Major Meta-Analyses:A 2024 Cochrane review included 34 studi...

Why it works: Immune-modulating compounds. Echinacea species (especially E. purpurea) contain polysaccharides, alkylamides and caffeic-acid derivatives that have been shown in lab studies to sti...

Instructions: Big caveat: Echinacea products vary greatly (species, part of plant, extraction method, fresh vs dried, dose). Clinical results vary accordingly. Follow product labels and talk to...

Warnings: Allergic reactions: People with allergies to plants in the Asteraceae/Compositae family (ragweed, ch...

Studies: Systematic reviews / meta-analysesCochrane review — Echinace...

Why it works: Camu camu can have 60 times more vitamin C than an orange and 56 times more than a lemon. This means camu camu may help feed the body the necessary nutrients it needs to properly r...

Instructions: Important Note: There isn't enough reliable information to know what an appropriate dose of camu camu might be. Keep in mind that natural products are not always necessarily safe a...

Warnings: Pregnancy and Breastfeeding: Pregnancy and breast-feeding: There isn't enough reliable information t...

Studies: Critical Limitation: People use camu camu for the common col...

Why it works: Garlic (Allium sativum) contains sulfur-containing compounds — especially allicin, ajoene and other organosulfur compounds — that show antiviral, antibacterial, anti-inflammatory a...

Instructions: Forms used in clinical research. • Allicin-containing garlic supplement — 1 capsule daily for 12 weeks: the 2001 randomized double-blind trial (Josling) used a commercial allicin-c...

Warnings: Bleeding risk / anticoagulants: garlic (especially in supplement form or high dietary amounts) can h...

Studies: Josling, 2001 (double-blind RCT, N=146) — an allicin-contain...

Why it works: Antiviral activity (in vitro). Elderberry extracts and specific polyphenols (especially anthocyanins such as cyanidin glycosides) have been shown in laboratory studies to bind vira...

Instructions: Important: products and concentrations vary. If you use elderberry, prefer commercial, standardized extracts/syrups (they’ve been heat-processed to remove toxins and have known pol...

Warnings: Raw/unprocessed parts are toxic. Raw elderberries (and leaves/stems/unripe berries) contain cyanogen...

Studies: Systematic reviews / evidence assessmentsWieland et al., BMC...

Why it works: Immune regulation & antimicrobial peptides. Vitamin D (the active form 1,25-diOH-D) binds the Vitamin D Receptor in immune cells and epithelial cells and upregulates genes for anti...

Instructions: Important: There’s no single universally-accepted “treatment” protocol to cure a cold with vitamin D. What follows is what trials and public-health bodies used or recommend for pre...

Warnings: Vitamin D toxicity (hypervitaminosis D): excessive intake can cause hypercalcemia (nausea, vomiting,...

Studies: Martineau AR et al., BMJ 2017 — Individual participant data...

Why it works: Active compounds: Thyme contains volatile oils (mainly thymol and carvacrol) plus phenolic compounds that have antimicrobial, antiviral (in vitro), anti-inflammatory, antispasmodic...

Instructions: Important: the strongest clinical support is for standardized thyme extracts and licensed herbal medicines (e.g., combination products such as thyme + ivy or thyme + primula) — not...

Warnings: A. Essential oils & toxicity. • Do not ingest undiluted thyme essential oil. Thyme oils contain conc...

Studies: Human clinical evidence (high-relevance items):Randomized, d...

Why it works: Monolaurin (glycerol monolaurate) shows strong in-vitro activity against enveloped viruses and some bacteria, but there is no good clinical evidence that taking monolaurin orally p...

Instructions: No standardized, evidence-based medical dosing for treating the common cold exists. Monolaurin is a dietary supplement, not an FDA-approved cold treatment, so no authoritative agen...

Warnings: Not well studied in pregnancy or breastfeeding. Experts commonly recommend avoiding medicinal-level...

Studies: Most evidence = in vitro (test-tube) or animal studies. Thes...

Why it works: Why it might work: propolis contains polyphenols/flavonoids with antiviral, anti-inflammatory and immunomodulatory effects shown in vitro and in animal models — plus some small hum...

Instructions: Below are what clinical studies actually used — use these as trial-based examples rather than official dosing recommendations. If you choose to try propolis, prefer standardized pr...

Warnings: Propolis is generally well tolerated in many people, but important safety issues include:. • Allergi...

Studies: Randomized trials & clinical studiesEsposito C. et al. —...

Why it works: The main biologically active alkaloid in goldenseal is berberine (plus other alkaloids such as hydrastine and canadine). Berberine has demonstrated antimicrobial, antiviral and ant...

Instructions: Common forms and typical (reported) dosing:. • Capsules / tablets: common supplement labels range around ~250–500 mg of goldenseal root extract taken 1–3 times daily (some practiti...

Warnings: Pregnancy & breastfeeding: Avoid goldenseal. It can stimulate uterine contractions and has been asso...

Studies: No high-quality clinical trials show goldenseal cures or rel...

Why it works: The main active compound, andrographolide, shows anti-inflammatory, antiviral and immunomodulatory effects in lab studies. These actions can reduce inflammation of the upper airway...

Instructions: Clinical trials used standardized oral extracts (not raw leaf tea) — products vary (e.g., SHA-10, Kan Jang, KalmCold/AP-Bio®). Typical regimens from trials include:. • 1200 mg/day...

Warnings: Allergic / anaphylactic reactions: Regulatory safety reviews (Australia’s TGA and New Zealand Medsaf...

Studies: Systematic reviews / meta-analysesHu X-Y et al. — systematic...