Daily Immune Foundation
About this protocol
Where to start
Start with vitamin D3 at 2000-4000 IU daily, with breakfast. Most adults are vitamin D-deficient or insufficient (especially in winter); supplementation reduces respiratory infection risk in deficient individuals.
Add zinc at 15-30 mg elemental daily with food. Required for over 300 enzymes including those critical for immune cell function. Don''t exceed 40 mg/day for extended periods (copper depletion).
Add vitamin C at 500-1000 mg daily. Modest cold-prevention effect; larger effect on duration when started at symptom onset.
Add quercetin at 500 mg daily for the broader antiviral and mast cell modulation effects. Particularly relevant for adults with seasonal allergies or frequent upper respiratory infections.
This is preventive/maintenance use. If you''re developing acute cold or flu symptoms, transition to Cold/Flu Recovery (Acute) — different dosing and additional ingredients (elderberry, NAC).
4 nutrients
Start here
Strongest evidence — the foundation of the stack.
Vitamin D3
2000-4000 IU daily, with breakfastVitamin D deficiency is the most common modifiable nutrient gap in adults, especially in winter. The Martineau 2017 IPD meta-analysis showed supplementation reduces respiratory infection risk, with the largest effect in those who were deficient at baseline (25-OH vitamin D < 25 nmol/L). Pair with vitamin K2 for cardiovascular safety. Fat-soluble; take with food.[1, 2, 3]
Zinc
15-30 mg elemental, with breakfastZinc is essential for immune cell function. Severe zinc deficiency dramatically impairs immunity; modest supplementation in replete adults has smaller effects. The Hemilä 2017 meta-analysis showed zinc lozenges (different formulation) reduce cold duration by ~30%. Picolinate and bisglycinate forms are well-absorbed for daily use. Do not exceed 40 mg/day for extended periods.[4, 5, 6]
Add if needed
Add these only if the foundation isn't enough.
Vitamin C
500-1000 mg daily, with breakfastThe Cochrane review of vitamin C and the common cold (Hemilä 2013) found that regular supplementation reduces cold incidence in adults under heavy physical stress (athletes, military) and modestly reduces cold duration (about 8%) in general populations. Effect size is small but the safety margin is wide. Higher doses (1-2 g+) cause loose stools — split AM/PM if needed.[7, 8, 9]
Quercetin (with bromelain)
500 mg daily, with breakfastQuercetin is a flavonoid with anti-inflammatory and mast cell stabilizing effects, plus broad antiviral activity in vitro. Heinz 2010 trial in physically active adults showed reduced upper respiratory infection rates with quercetin supplementation. Often co-formulated with bromelain for enhanced absorption.[10, 11, 12]
Warnings
Lifestyle improvements
Sleep is the single highest-leverage immune intervention
A single night of poor sleep reduces natural killer cell activity by ~70%. Chronic short sleep is one of the strongest predictors of infection susceptibility in cohort studies. Aim for 7-9 hours consistently.
Stress management
Chronic stress suppresses immune function measurably. Cortisol elevation impairs T-cell and B-cell responses. The Daily Calm and Anxiety Relief protocols complement here.
Exercise — moderate, not extreme
150-300 minutes of moderate exercise weekly improves immune function. Extreme endurance training (multi-hour workouts, marathon training) transiently SUPPRESSES immunity (the "open window" phenomenon — explains why endurance athletes get sick after major events).
Diversity of vegetables and fruits
Plant phytochemicals support diverse immune-relevant pathways. Aim for variety — different colors, different families. The American Gut Project found people eating 30+ different plant species/week had measurably better gut microbiome diversity than those eating fewer than 10.
Adequate protein
Antibodies are proteins. Severe protein restriction impairs antibody production. Aim for 1.2-1.6 g/kg body weight daily.
Vitamin D from sunlight when possible
10-30 minutes of midday outdoor sun exposure (without sunscreen for vitamin D) can provide significant vitamin D synthesis depending on skin tone and latitude. Supplementation is more reliable in winter or higher latitudes.
Limit alcohol
Alcohol suppresses immune function for 24-48 hours after even moderate drinking. Heavy use produces sustained immune suppression.
Stop smoking
Smoking damages respiratory epithelial immune defenses and is one of the strongest reversible infection risk factors.
Vaccinations
Flu vaccine annually, COVID boosters per current guidance, shingles vaccine at 50+, pneumonia vaccine at 65+ (or earlier with risk factors). Supplements don''t replace vaccines.
Hand hygiene
Frequent handwashing remains one of the most-evidenced infection prevention interventions, especially in cold/flu season.
References
- Vitamin D — supplement research overviewExamine.com link
- Martineau AR, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017;356:i6583.PubMed link
- Jolliffe DA, et al. Vitamin D supplementation to prevent acute respiratory infections: a systematic review and meta-analysis of aggregate data from randomised controlled trials. Lancet Diabetes Endocrinol. 2021;9(5):276-292.PubMed link
- Zinc — supplement research overviewExamine.com link
- Hemilä H. Zinc lozenges and the common cold: a meta-analysis. JRSM Open. 2017;8(5):2054270417694291.PubMed link
- Wessels I, et al. Zinc as a Gatekeeper of Immune Function. Nutrients. 2017;9(12):1286.PubMed link
- Vitamin C — supplement research overviewExamine.com link
- Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev. 2013;(1):CD000980.PubMed link
- Carr AC, Maggini S. Vitamin C and Immune Function. Nutrients. 2017;9(11):1211.PubMed link
- Quercetin — supplement research overviewExamine.com link
- Heinz SA, et al. Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial. Pharmacol Res. 2010;62(3):237-242.PubMed link
- Li Y, et al. Quercetin, Inflammation and Immunity. Nutrients. 2016;8(3):167.PubMed link
Related protocols
Other immunity protocols and protocols sharing ingredients with this one.
Seasonal Allergy Relief
immunity
Seasonal allergies (hay fever, allergic rhinitis, allergic conjunctivitis) affect 20-30% of adults — and the supplement category for them is dramatically under-developed relative to the demand. The mechanism behind allergy symptoms is mast cell histamine release in response to pollens, mold, or other seasonal allergens. The supplements with the strongest mast-cell-stabilizing and antihistamine evidence are quercetin (the most-studied natural antihistamine), vitamin C (modest antihistamine activity at higher doses), and stinging nettle (small trials specifically for allergic rhinitis). Butterbur has rigorous trial evidence comparable to cetirizine but requires PA-free formulations and short-course use. This stack is for mild-to-moderate seasonal symptoms and as a complement to standard antihistamines. Severe asthma or anaphylaxis-prone individuals need a proper allergist evaluation, not a supplement protocol.
Cold/Flu Recovery (Acute)
immunity
Acute upper respiratory infection treatment is fundamentally different from daily immune support — different dosing, different ingredients, and a short-cycle (7-10 day) approach rather than chronic supplementation. The supplements with the best acute evidence are elderberry (Sambucus nigra) for influenza specifically, high-dose zinc lozenges (zinc acetate or gluconate) for cold duration reduction, vitamin C at higher doses started at symptom onset, and NAC for mucus thinning and antioxidant support. The Cochrane reviews on these are reasonably positive for elderberry and zinc; vitamin C is modest; NAC has clean evidence for respiratory symptom reduction. This is a 7-day protocol — START at first symptom (sore throat, fatigue, body aches before the cold/flu is fully established) and continue through resolution. If you have severe symptoms (high fever, difficulty breathing, dehydration, chest pain), are at high risk (over 65, immunocompromised, pregnant, multiple comorbidities), or symptoms worsen instead of improving after 5-7 days — see your doctor. Bacterial pneumonia, flu requiring antivirals, and COVID requiring monitoring all need medical attention beyond supplementation.
Men's Essentials 30-50
general· 2 shared ingredients
The decade between 30 and 50 is when men start to drift from "automatic health" into actively maintained health. Testosterone declines ~1% per year starting around 30, cardiovascular risk markers begin shifting, lean muscle mass starts to decrease without active training, and small recovery imbalances accumulate. This protocol is the everyday foundation specifically calibrated for men in this window: vitamin D, magnesium, omega-3, zinc, and CoQ10. Each addresses a relevant pathway — testosterone synthesis, cardiovascular protection, sleep and stress, mitochondrial energy. Layer goal-specific protocols (Testosterone Support, Foundational Longevity, Joint Health) on top of this baseline as needed.
Skin & Collagen Support
beauty· 2 shared ingredients
Skin appearance is driven by hydration, collagen turnover, oxidative stress, and UV damage — most of which are downstream of lifestyle. Supplements can support but not replace topical sunscreen, sleep, hydration, and a diverse diet. The strongest evidence is for hydrolyzed collagen peptides (multiple trials show improvements in skin hydration and elasticity after 8-12 weeks) and vitamin C (cofactor in collagen synthesis). Hyaluronic acid taken orally has emerging evidence for skin hydration. The "anti-aging" supplement category is rife with overpromising — the gains are real but modest, and 90% of skin appearance comes from sun protection and not smoking.
Thyroid Support — Hashimoto's
thyroid· 2 shared ingredients
Hashimoto''s thyroiditis is the most common cause of hypothyroidism in iodine-replete countries — autoimmune destruction of thyroid tissue driving elevated TPO antibodies and eventual hypothyroid state. Treatment of confirmed hypothyroidism is levothyroxine; supplements DO NOT replace thyroid hormone replacement. They CAN reduce TPO antibody levels, support thyroid function in early/subclinical Hashimoto''s, and address common cofactor deficiencies that worsen disease progression. The strongest evidence in the supplement category is for selenium (Grade A in recent meta-analyses for TPO antibody reduction), vitamin D3 (Grade B), and the combination of myo-inositol + selenium (Grade B). If you have a confirmed Hashimoto''s diagnosis, this stack complements your endocrinologist''s management, doesn''t replace it. If you suspect Hashimoto''s, get TSH, free T4, free T3, TPO antibodies, and thyroglobulin antibodies before starting.
Women's Libido & Desire
hormones· 2 shared ingredients
Female sexual desire is multifactorial — hormonal status (estrogen, testosterone, progesterone, thyroid), relationship dynamics, mental health, stress, sleep, medication side effects (especially SSRIs and oral contraceptives), and physical comfort all matter, often more than any single supplement. Hypoactive Sexual Desire Disorder (HSDD) affects roughly 1 in 10 women, and the most common drivers in our culture are chronic stress, sleep debt, medication side effects, and relational rather than biochemical factors. Supplements address one slice of the picture and are not a substitute for proper medical evaluation when desire loss is severe or distressing. That said, a handful of supplements have real trial evidence in women specifically — not extrapolated from male data. Maca has the most consistent evidence for libido and desire in both pre- and postmenopausal women, with effects that appear independent of hormonal change. Ashwagandha shows benefit on female sexual function through stress modulation. Vitamin D and zinc are deficiency-correction nutrients — if you''re low, repletion helps; if you''re replete, additional supplementation does nothing. L-citrulline has indirect support for genital blood flow. Most women''s libido issues are NOT supplement-deficiency problems, but for the subset where they are, this stack is well-targeted.
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Coming to App StoreDisclaimer: These statements have not been evaluated by the FDA. This protocol is educational, not a substitute for personalized medical advice. Talk to your doctor before starting any new supplement regimen — especially if you're pregnant, breastfeeding, on medications, or managing a chronic condition. Last updated 5/20/2026.