Protocol · Immune Health
Upper Respiratory Tract Infection (Common Cold) Prevention & Support Protocol
Vitamin C and Zinc are the core of this stack, with 7 supporting supplements. Each row gives the amount the protocol lists and the grade our evidence database holds for that supplement in Upper Respiratory Tract Infection (Common Cold) Prevention & Support.
We are re-verifying the studies cited on protocol pages; only confirmed citations are shown.
The stack
9 supplements · 6 graded · 7 confirmed studies
| Grade | Supplement | Amount listed | Why it’s in the stack | Evidence on file | Shop |
|---|---|---|---|---|---|
| Primary stackThe core of this protocol | |||||
| Vitamin C | Amount listed: 200–1,000 mg daily for prevention; 1–2 g daily during illness | Supports immune cell function; regular supplementation reduces cold duration and severity, especially in physically stressed individuals
| Grade D for Common Cold Symptoms1 study · 1,731 people | ||
Confirmed studies for Vitamin C (titles as PubMed lists them) | |||||
| Zinc | Amount listed: 15–30 mg daily prevention; 75 mg+ daily as lozenges (acetate or gluconate) when ill | Inhibits viral replication; zinc lozenges taken within 24 hours of symptom onset can reduce cold duration
| Grade D for Upper Respiratory Tract Infection Risk1 study · 100 people | ||
Confirmed studies for Zinc (titles as PubMed lists them) | |||||
| Supporting stackListed as additions to the core | |||||
| Beta-Glucans | Amount listed: 250–500 mg daily | Immunomodulators that enhance innate immune response; may reduce URTI incidence and duration
| Grade B for Upper Respiratory Tract Infection Risk1 study · 2,465 people | ||
| Vitamin D | Amount listed: 1,000–4,000 IU daily (based on blood levels) | Supports innate immunity via cathelicidin production; deficiency increases respiratory infection risk
| Grade C for Bacterial Infection140 people | ||
Confirmed studies for Vitamin D (titles as PubMed lists them) | |||||
| Echinacea | Amount listed: 300–500 mg extract 3× daily at onset of symptoms | Immunostimulant that may reduce cold incidence and duration; most effective when taken early
| Grade C for Common Cold Symptoms9 studies · 567 people | ||
Confirmed studies for Echinacea (titles as PubMed lists them) | |||||
| Elderberry (Sambucus nigra) | Amount listed: 175 mg extract 2–4× daily or 15 mL syrup 4× daily when ill | Antiviral properties against influenza and some cold viruses; may reduce duration and severity
| Not graded yet | ||
Confirmed studies for Elderberry (Sambucus nigra) (titles as PubMed lists them) | |||||
| Andrographis (King of Bitters) | Amount listed: 200–400 mg standardized extract daily | Traditional herb with immunostimulatory effects; may reduce severity and duration of URTI symptoms | Not graded yet | ||
| Pelargonium sidoides (Umckaloabo) | Amount listed: 30–60 drops 3× daily or 20 mg extract 3× daily | Stimulates immune response and may have direct antiviral effects; studied for acute bronchitis and URTIs
| Grade C for Asthma Symptoms1 study · 61 people | ||
| Probiotics | Amount listed: 5–10 billion CFU daily (Lactobacillus and Bifidobacterium strains) | Support gut-immune axis; may reduce respiratory infection incidence and duration | Not graded yet | ||
Confirmed studies for Probiotics (titles as PubMed lists them) | |||||
Shop the evidence-backed picks
The collection holds the supplements we grade A or B for its theme, in third-party tested products where the catalog has them. It opens in our Fullscript store. You can look through it without signing in; Fullscript asks for a free account to order.
Or shop one supplement
The supplement in this protocol graded A or B. Each opens third-party tested products, matched to the dose above where we can.
- Grade B
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How this protocol works
In plain language
Upper respiratory tract infections (URTIs)—including the common cold, pharyngitis, and sinusitis—are among the most frequent illnesses people experience. Most are viral and self-limiting, but they cause significant discomfort and missed work/school. Adults average 2-4 colds per year; children even more. While there's no cure for the common cold, certain supplements can help prevent infections and reduce their duration and severity.
IMPORTANT: Most URTIs are viral and don't require antibiotics. See a doctor if symptoms are severe, prolonged (>10 days), or you have high fever, severe headache, or difficulty breathing.
- Vitamin C supports multiple immune functions. While it doesn't prevent colds in the general population, regular supplementation reduces cold duration by about 8% in adults and 14% in children. In people under physical stress (athletes, soldiers), it can cut cold incidence in half. Taking higher doses at the onset of symptoms may help.
- Zinc lozenges are one of the most effective treatments when taken within 24 hours of cold symptom onset. Zinc interferes with viral replication in the throat. Studies show it can reduce cold duration by about 33%. The key is using the right form (acetate or gluconate) and adequate doses.
- Beta-Glucans are compounds from yeast, mushrooms, and oats that prime the immune system. They enhance the activity of immune cells like macrophages and natural killer cells. Studies show they can reduce the frequency and severity of URTIs.
- Vitamin D is crucial for immune function. People with low vitamin D levels are significantly more likely to get respiratory infections. Supplementation reduces infection risk, especially in those who are deficient. The effect is most pronounced in daily/weekly (not single high-dose) supplementation.
- Echinacea has been used traditionally for colds for centuries. While study results are mixed (partly due to different preparations), some evidence suggests it can modestly reduce cold incidence and duration when taken at symptom onset.
- Elderberry has antiviral properties and has been shown to reduce the duration and severity of colds and flu. It works by inhibiting viral replication and enhancing the immune response.
- Andrographis (King of Bitters) is used in Ayurvedic and Chinese medicine for infections. Studies suggest it may reduce the severity and duration of cold symptoms.
- Pelargonium sidoides (Umckaloabo) is a South African traditional remedy. Clinical trials show it can reduce symptom severity and duration of acute bronchitis and some URTIs.
- Probiotics support the gut-immune connection. Regular use may reduce the number of respiratory infections, their duration, and the need for antibiotics.
Expected timeline: Zinc lozenges: effects begin within hours/days of onset. Vitamin C: ongoing benefit with regular use. Beta-glucans/Vitamin D/Probiotics: 2-4 weeks for prevention effects to establish. Echinacea/Elderberry/Andrographis: best when started at first sign of illness.