Is a higher dose always better?

No. Dose-fit rewards landing inside the range studied for the outcome — over-dosing (common with melatonin) or under-dosing both lower the score. The goal is the effective dose, not the biggest number.

What does the Value score mean?

The Value score compares a product's price per serving with clinically relevant products ranked for the same outcome. A score of 50 is the typical price; above 50 means better value than typical, while below 50 means the product costs more than typical. It is a 0–100 value signal, not a percentile.

Why is the cheapest product not #1?

Cost is only one input. The cheapest pick here is a citrate form with weaker absorption and a stock-risk flag, so it leads on Value-for-cost but trails on the composite that also weighs evidence, dose fit and availability.

Are these affiliate links?

Retailer links may be affiliate links and DoseRank may earn a commission. Rankings and placement are determined by the scoring model only — never by payment from a brand.

Is this medical advice?

No. DoseRank summarizes evidence to help you choose; it is not a substitute for a clinician, especially if you are pregnant, breastfeeding, on medication, or managing a health condition.

Reduce respiratory infections

What this outcome means

Respiratory infection incidence is how often you come down with colds, flu, and other infections of the airways over time. On DoseRank it maps to a defined health outcome built from human studies on infection episode counts, illness duration, and days symptomatic – data sourced from open sources and specialized resources. DoseRank is not medical advice.

Who it's for

Frequently sickPeople who catch one airway infection after another each season.

High-exposure settingsThose in crowded schools, offices, or transit hubs daily.

Vulnerable airwaysOlder adults or those whose defenses leave them prone to infection.

Stack buildersAlready taking supplements such as Vitamin D3 (Cholecalciferol) and want the dose right.

Evidence level

92Strong

Vitamin D3 (Cholecalciferol) – has strong public evidence. DoseRank looks at both evidence quality and formula fit. A DoseFit Score of 91 means this product's ingredient forms and doses are close to what was used in the studies behind this ranking - DoseRank weights each product ingredient.

Best ingredients

Vitamin D3 (Cholecalciferol) is the best supported ingredient signal for this outcome.

Dose matchedDoseFit 91

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: Above range: Vitamin D3 (Cholecalciferol) 5000 IU vs 400-4000 IU.

Processed

Available

Ingredients

Brands

508

Coverage

100%

How to read the scores

What every metric means

Each score is 0–100. Higher is better for every metric below.

CompositeThe overall DoseRank score — a weighted blend of clinical strength, evidence, dose fit, trust and value.Higher is better

ClinicalHow strongly the formula's ingredients and doses match what clinical studies used for this outcome.Higher is better

EvidenceHow much published human research backs the formula's key ingredients for this outcome — both how many studies exist and how strong they are.Higher is better

ValueHow the price per serving compares with similar products for this outcome — 50 is the typical price, higher means better value for your money.Higher is better

TrustHow well customers rate this product, with extra weight given to ratings backed by a large number of reviews.Higher is better

PopularityHow strongly this product sells compared with the other ranked products for this outcome.Higher is better

This legend covers the scores on this page — for data sources, scoring weights, and limits, read the full methodology →

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Get a personal report

A saved, shareable breakdown: your matched products, dose math, interaction flags to discuss with a clinician, and a price-tracked stack you can revisit.

Questions

Frequently asked

Each product gets a composite score blending clinical strength, evidence, dose fit, trust and value. The #1 on the DoseRank tab has the highest composite; the other tabs re-rank the same products by Value, Trust, or Popularity. Placement is never paid.

Reduce respiratory infections

What this outcome means

Who it's for

Frequently sickPeople who catch one airway infection after another each season.

High-exposure settingsThose in crowded schools, offices, or transit hubs daily.

Vulnerable airwaysOlder adults or those whose defenses leave them prone to infection.

Stack buildersAlready taking supplements such as Vitamin D3 (Cholecalciferol) and want the dose right.

Evidence level

92Strong

Best ingredients

Vitamin D3 (Cholecalciferol) is the best supported ingredient signal for this outcome.

Dose matchedDoseFit 91

Scores reward products dosed inside or above the studied range, not just the right ingredient. Examples: Above range: Vitamin D3 (Cholecalciferol) 5000 IU vs 400-4000 IU.

Processed

Available

Ingredients

Brands

508

Coverage

100%

Relevant ingredients

Which ingredient types matter for respiratory infection incidenceOpen to see which ingredient types matter for respiratory infection incidence

3.9k products across 6 ingredient types — open to filter the ranking.

Use types to filter ranked products

Vitamins

3.7k products

Essential micronutrients the body can't make in sufficient amounts. Fat-soluble ones (A, D, E, K) store up; water-soluble ones need regular topping-up.

Typical: ,

Probiotics & Microorganisms

92 products

Live beneficial bacteria and yeasts measured in CFUs. Strain identity and viability at expiry matter far more than headline colony counts.

Typical:

Fatty Acids & Lipids

45 products

Dietary fats including omega-3s and structural lipids. Look at the active EPA/DHA amounts and freshness, since oils oxidize and turn rancid.

Typical:

Glandulars & Animal-Derived Extracts

45 products

Animal gland and organ-tissue extracts used traditionally for targeted organ support. Purity and grass-fed sourcing are the key quality markers.

Typical:

Botanicals/Herbal Extracts

9 products

Concentrated plant and herbal extracts standardized to actives. Potency depends on the extract ratio and marker content, not raw weight.

Typical:

Antioxidants & Bioactive Compounds

32 products

Molecules that neutralize free radicals and tune cell signaling. Helpful in balance; mega-doses can blunt the body's own adaptive defenses.

Typical:

Top decision cards

Best products for respiratory infection incidence

Ranking by · Composite outcome score

Best overall — the composite outcome score.

Top pick · DoseRank

Why this ranks #1 for respiratory infection incidence

Micro Ingredients, Vitamin D3 + K2, 300 Softgels

Micro Ingredients$0.09 / serving4.9 · 2,088Available now

Also helps with

Vitamin K status

Vitamin D status

Bone mineral density

Why this ranks here

Evidence fitVitamin D3 (Cholecalciferol) is the strongest evidence signal for this outcome.
Dose fitVitamin D3 (Cholecalciferol) at 5000 IU is higher than the studied 400-4000 IU window.
Price / serving$0.09 per serving — low price tier for this outcome.
AvailabilityIn stock across major retailers; 99% availability confidence.
TrustStrong trust signals — consistently high marks from verified buyer ratings.

Trade-offs

Evidence depth trails the rest of this list

The numbers

5000 IUAbove rangehigher than the studied 400-4000 IU window

Compare top 3 Product data Open at retailer

The rest of the ranking · DoseRank

Top 10 ranked products

ChildLife Essentials, Vitamin D3, Natural Berry, 12.5 mcg (500 IU), 1 fl oz (30 ml)

ChildLife EssentialsClinical87Dose fit67Popularity98$0.08/ serving

Natural Factors, Super Cod Liver Oil, 90 Softgels

Natural FactorsClinical89Dose fit54Popularity68$0.10/ serving

Paradise Herbs, Earth's Blend, Vitamin D3, 90 Vegetarian Capsules

Paradise HerbsClinical89Dose fit91Popularity50$0.12/ serving

Paradise Herbs, Earth's Blend®, One Daily Superfood Multi-Vitamin, No Iron, 120 Vegetarian Capsules

Paradise HerbsClinical87Dose fit71Popularity91$0.22/ serving

Paradise Herbs, Earth's Blend, One Daily Superfood Multi-Vitamin with Iron, 120 Vegetarian Capsules

Paradise HerbsClinical87Dose fit71Popularity84$0.22/ serving

Amazing Nutrition, Amazing Formulas, Calcium Magnesium Zinc + Vitamin D3, 300 Tablets

Amazing NutritionClinical87Dose fit68Popularity76$0.16/ serving

Solaray, Vitamin D3 + K2, 60 VegCaps

SolarayClinical87Dose fit91Popularity98$0.31/ serving

Codeage, Clearface Vitamins+, 90 Vegetable Capsules

CodeageClinical91Dose fit56Popularity68$0.60/ serving

KAL, Ultra D-3, Unflavored, 250 mcg (10,000 IU), 90 Micro Tablets

KALClinical89Dose fit94Popularity30$0.15/ serving