How does DoseRank decide what ranks #1?

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.

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.

DOSERANKEVIDENCE-BASED SUPPLEMENTS

Improve vitamin A status

DOSERANKEVIDENCE-BASED SUPPLEMENTS

Best Supplements for Vitamin A status — 2494 Ranked | DOSERANK

Top decision cards

Best products for vitamin a status

Ranking by · Composite outcome score

Best overall — the composite outcome score.

Top pick · DoseRank

Why this ranks #1 for vitamin a status

NOW Foods, Cod Liver Oil, 650 mg, 250 Softgels

NOW Foods$0.05 / serving4.7 · 2,757Available now

Also helps with

Night vision or dark adaptation

Immune function

Respiratory infection incidence

Why this ranks here

Evidence fitRetinyl Palmitate and Cod Liver Oil are the strongest evidence signals for this outcome.
Dose fit2 of 2 dosed ingredients land in the studied range. Retinyl Palmitate at 750 mcg (calculated) lands inside the studied 700-3000 mcg window.
Price / serving$0.05 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.

The numbers

750 mcg (calculated)In rangeinside the studied 700-3000 mcg window

650 mgIn rangeinside the studied 500-3000 mg window

6.8 mcg

Compare top 3 Product data Open at retailer

The rest of the ranking · DoseRank

Top 10 ranked products

Natural Factors, Super Cod Liver Oil, 90 Softgels

Natural FactorsClinical97Dose fit70Popularity68$0.10/ serving

NOW Foods, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

NOW FoodsClinical89Dose fit75Popularity99$0.05/ serving

NOW Foods, Vitamin A, 7,500 mcg (25,000 IU), 250 Softgels

NOW FoodsClinical89Dose fit91Popularity91$0.06/ serving

NOW Foods, Vitamin A&D, 100 Softgels

NOW FoodsClinical89Dose fit90Popularity91$0.05/ serving

Solgar, Dry Vitamin A, 100 Tablets

SolgarClinical89Dose fit75Popularity91$0.07/ serving

Bluebonnet Nutrition, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

Bluebonnet NutritionClinical89Dose fit90Popularity91$0.08/ serving

Natural Factors, Vitamin A, 3,000 mcg (10,000 IU), 180 Softgels

Natural FactorsClinical89Dose fit90Popularity80$0.03/ serving

21st Century, Vitamin A, 3,000 mcg (10,000 IU), 110 Softgels

21st CenturyClinical89Dose fit90Popularity84$0.05/ serving

21st Century, One Daily, Women's, 100 Tablets

21st CenturyClinical89Dose fit70Popularity99$0.07/ serving

Top decision cards

Best products for vitamin a status

Ranking by · Composite outcome score

Best overall — the composite outcome score.

Top pick · DoseRank

Why this ranks #1 for vitamin a status

NOW Foods, Cod Liver Oil, 650 mg, 250 Softgels

NOW Foods$0.05 / serving4.7 · 2,757Available now

Also helps with

Night vision or dark adaptation

Immune function

Respiratory infection incidence

Why this ranks here

Evidence fitRetinyl Palmitate and Cod Liver Oil are the strongest evidence signals for this outcome.
Dose fit2 of 2 dosed ingredients land in the studied range. Retinyl Palmitate at 750 mcg (calculated) lands inside the studied 700-3000 mcg window.
Price / serving$0.05 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.

The numbers

750 mcg (calculated)In rangeinside the studied 700-3000 mcg window

650 mgIn rangeinside the studied 500-3000 mg window

6.8 mcg

Compare top 3 Product data Open at retailer

The rest of the ranking · DoseRank

Top 10 ranked products

Natural Factors, Super Cod Liver Oil, 90 Softgels

Natural FactorsClinical97Dose fit70Popularity68$0.10/ serving

NOW Foods, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

NOW FoodsClinical89Dose fit75Popularity99$0.05/ serving

NOW Foods, Vitamin A, 7,500 mcg (25,000 IU), 250 Softgels

NOW FoodsClinical89Dose fit91Popularity91$0.06/ serving

NOW Foods, Vitamin A&D, 100 Softgels

NOW FoodsClinical89Dose fit90Popularity91$0.05/ serving

Solgar, Dry Vitamin A, 100 Tablets

SolgarClinical89Dose fit75Popularity91$0.07/ serving

Bluebonnet Nutrition, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

Bluebonnet NutritionClinical89Dose fit90Popularity91$0.08/ serving

Natural Factors, Vitamin A, 3,000 mcg (10,000 IU), 180 Softgels

Natural FactorsClinical89Dose fit90Popularity80$0.03/ serving

21st Century, Vitamin A, 3,000 mcg (10,000 IU), 110 Softgels

21st CenturyClinical89Dose fit90Popularity84$0.05/ serving

21st Century, One Daily, Women's, 100 Tablets

21st CenturyClinical89Dose fit70Popularity99$0.07/ serving

Improve vitamin A status

Improve vitamin A status

Which ingredient types matter for vitamin a statusOpen to see which ingredient types matter for vitamin a status

Vitamins

Fatty Acids & Lipids

Glandulars & Animal-Derived Extracts

Antioxidants & Bioactive Compounds

Best products for vitamin a status

NOW Foods, Cod Liver Oil, 650 mg, 250 Softgels

Natural Factors, Super Cod Liver Oil, 90 Softgels

NOW Foods, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

NOW Foods, Vitamin A, 7,500 mcg (25,000 IU), 250 Softgels

NOW Foods, Vitamin A&D, 100 Softgels

Solgar, Dry Vitamin A, 100 Tablets

Bluebonnet Nutrition, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

Natural Factors, Vitamin A, 3,000 mcg (10,000 IU), 180 Softgels

21st Century, Vitamin A, 3,000 mcg (10,000 IU), 110 Softgels

21st Century, One Daily, Women's, 100 Tablets

What every metric means

Compare the top 3, side by side

Not sure which is right for you?

Get a personal report

Frequently asked

Which ingredient types matter for vitamin a statusOpen to see which ingredient types matter for vitamin a status

Vitamins

Fatty Acids & Lipids

Glandulars & Animal-Derived Extracts

Antioxidants & Bioactive Compounds

Best products for vitamin a status

NOW Foods, Cod Liver Oil, 650 mg, 250 Softgels

Natural Factors, Super Cod Liver Oil, 90 Softgels

NOW Foods, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

NOW Foods, Vitamin A, 7,500 mcg (25,000 IU), 250 Softgels

NOW Foods, Vitamin A&D, 100 Softgels

Solgar, Dry Vitamin A, 100 Tablets

Bluebonnet Nutrition, Vitamin A, 3,000 mcg (10,000 IU), 100 Softgels

Natural Factors, Vitamin A, 3,000 mcg (10,000 IU), 180 Softgels

21st Century, Vitamin A, 3,000 mcg (10,000 IU), 110 Softgels

21st Century, One Daily, Women's, 100 Tablets

Compare the top 3, side by side