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Vitamin D-3, High Potency, 5,000 IU, 240 Softgels vs Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK

Side-by-side comparison of scores, ingredients, prices and real customer feedback for Vitamin D-3, High Potency, 5,000 IU, 240 Softgels and Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK.

Last verified: 07 Apr 2026 · Based on 67 reviews

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82.0
Quick Answer

Vitamin D-3, High Potency, 5,000 IU, 240 Softgels scores 82.0/100 vs Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK at 80.0/100. Vitamin D-3, High Potency, 5,000 IU, 240 Softgels wins on effectiveness, ingredient quality, value for money. Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK is stronger on side effects and certifications.

How Do the Scores Compare?

Vitamin D-3, High Potency, ...
Nutravita Vitamin D3 4000 i...
Vitamin D-3, High Potency, 5,000 IU, 240 Softgels
Vitamin D-3, High Potency, ...
NOW Foods
 Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK
Nutravita Vitamin D3 4000 i...
Nutravita
Overall Score 82.0 80.0
Effectiveness 85.0/100
Best
 80.0/100
Ingredient Quality 83.0/100
Best
 77.0/100
Value for Money 91.0/100
Best
 90.0/100
Side Effects 87.0/100 88.0/100
Best
Certifications 52.0/100 62.0/100
Best
Best Price £11.93 iHerb → £8.99 Amazon UK →
Cheapest
Form None Softgel
Dose None 116 Grams
Third-Party Tested ✗ No ✗ No
Reviews Analysed 50 17

Vitamin D-3, High Potency, 5,000...

Pros

  • ✓Cholecalciferol (D3) in olive oil — correct form and fat-soluble delivery for meaningful absorption
  • ✓240 softgels at 5,000 IU is exceptional value; multiple reviewers explicitly note how long a single purchase lasts
  • ✓Tiny, tasteless, odourless softgels — easy to swallow, praised consistently across dozens of reviews
  • ✓Several reviewers confirm blood levels normalised after taking this at a doctor-recommended 5,000 IU dose

Cons

  • ✗Not vegan — bovine gelatin capsule shell rules it out for plant-based users
  • ✗No independent third-party purity or potency testing (no NSF, USP, or equivalent verification)
  • ✗5,000 IU is a therapeutic dose, not a maintenance dose — appropriate only with confirmed deficiency and blood monitoring
  • ✗No K2 included; several reviewers specifically flag that K2 should be taken separately to direct calcium properly

Best For

People with confirmed vitamin D deficiency via blood test, especially those prescribed 5,000 IU by a doctor Those in northern climates or low-sunlight regions needing reliable year-round supplementation Budget-conscious buyers wanting a clean, high-potency D3 without inflated branding costs
iHerb £11.93
View full review →

Nutravita Vitamin D3 4000 iu - 4...

Pros

  • ✓Small, easy-to-swallow softgels praised by virtually every reviewer, including those with tablet-swallowing difficulties
  • ✓Excellent value for money — 400 softgels lasts over a year at one-per-day dosing
  • ✓Clean formula with no fillers, bulking agents, or anti-caking agents — just D3, sunflower oil, and gelatin
  • ✓High 4000 IU dose meets medically recommended therapeutic levels for deficiency without needing multiple capsules

Cons

  • ✗Gelatin (bovine) capsule — not suitable for vegetarians or vegans
  • ✗No independent third-party certification (no USP, NSF, or equivalent)
  • ✗4000 IU exceeds general population guidelines; those without confirmed deficiency should consult a doctor before use
  • ✗Not recommended for under-18s per product labelling, limiting household sharing

Best For

UK residents with limited sun exposure during autumn and winter People diagnosed with or at risk of vitamin D deficiency Adults who struggle to swallow large tablets or capsules Those wanting a clean-label supplement with minimal additives Budget-conscious buyers seeking a long-lasting supply
Amazon UK £8.99
View full review →

What does the data say about Vitamin D-3, High Pote... vs Nutravita Vitamin D3 4...?

Vitamin D-3, High Potency, 5,000 IU, 240 Softgels Winner 82.0/100

5,000 IU of cholecalciferol delivered in an extra virgin olive oil base — the fat-soluble carrier is correct science, not a gimmick.

Effectiveness
Vitamin D-3, Hig..
85.0/100
Nutravita Vitami..
80.0/100
Ingredient Quality
Vitamin D-3, Hig..
83.0/100
Nutravita Vitami..
77.0/100
Value for Money
Vitamin D-3, Hig..
91.0/100
Nutravita Vitami..
90.0/100
Side Effects
Vitamin D-3, Hig..
87.0/100
Nutravita Vitami..
88.0/100
Certifications
Vitamin D-3, Hig..
52.0/100
Nutravita Vitami..
62.0/100

What are the key differences?

Vitamin D-3, High Poten.. is best for: People with confirmed vitamin D deficiency via blood test, especially those prescribed 5,000 IU by a doctor, Those in northern climates or low-sunlight regions needing reliable year-round supplementation
Nutravita Vitamin D3 40.. is best for: UK residents with limited sun exposure during autumn and winter, People diagnosed with or at risk of vitamin D deficiency

Frequently Asked Questions

Which is better, Vitamin D-3, High Potency, 5,000 IU, 240 Softgels or Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK? ▼
Vitamin D-3, High Potency, 5,000 IU, 240 Softgels scores 82.0/100 overall while Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK scores 80.0/100. Vitamin D-3, High Potency, 5,000 IU, 240 Softgels comes out ahead, scoring higher on effectiveness (85.0 vs 80.0). Vitamin D-3, High Potency, 5,0 is best suited for People with confirmed vitamin D deficiency via blood test, especially those prescribed 5,000 IU by a doctor and Those in northern climates or low-sunlight regions needing reliable year-round supplementation. Nutravita Vitamin D3 4000 iu - is better for UK residents with limited sun exposure during autumn and winter and People diagnosed with or at risk of vitamin D deficiency.
Is Vitamin D-3, High Potency, 5,000 IU, 240 Softgels worth the price compared to Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK? ▼
Vitamin D-3, High Potency, 5,000 IU, 240 Softgels costs £11.93 while Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK is £8.99. For value, Vitamin D-3, High Potency, 5,000 IU, 240 Softgels scores 91.0/100 vs Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK's 90.0/100. Vitamin D-3, High Potency, 5,000 IU, 240 Softgels delivers better value relative to its quality.
Which has fewer side effects? ▼
Vitamin D-3, High Potency, 5,000 IU, 240 Softgels scores 87.0/100 for side effects (higher means fewer reported issues) while Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK scores 88.0/100. Reviewers report fewer side effects with Nutravita Vitamin D3 4000 iu - 400 High Strength Easy to Swallow Premium Softgels - Over A Year's Supply - Max Strength Vitamin D3 Cholecalciferol Supplement - Manufactured in The UK. For certification and testing, Vitamin D-3, High Po scores 52.0/100 vs Nutravita Vitamin D3's 62.0/100. Always consult a healthcare professional before starting any supplement.

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What the Data Says

Why do 97% of UK vitamin D supplements lack third-party certification?

Only 1 out of 35 vitamin D products we scored has independent certification. That's 97% without any third-party verification of purity, potency, or label accuracy.

This is worse than most supplement categories. The reason is simple: UK law doesn't require it, and testing costs money. Most vitamin D brands sell on price alone, especially in the D3-only space where the raw ingredient is cheap. Certification adds cost that budget brands won't absorb.

What does this mean for you? Without third-party testing, you're trusting the manufacturer's label claims. A 2021 study in Nutrients found that vitamin D supplements varied from 52% to 135% of their labelled dose. That's a problem if you're relying on a specific daily intake.

Among the 35 products we scored, the top performers are all from brands with strong manufacturing track records: NOW Foods D3 5000 IU and Thorne Vitamin D + K2 both score 87/100 overall. Thorne holds the highest certification score in the category at 85/100. If independent testing matters to you, that's the product to look at.

Do you need vitamin K2 with high-dose vitamin D?

Probably yes at high doses, and our data backs the pairing. Thorne Vitamin D + K2 Liquid is the only D3+K2 combo product in our 35-product database that scores 87/100 overall, matching the top-ranked D3-only options from NOW Foods. It also holds the highest certification score in the category at 85/100.

Here's the science behind it. Vitamin D increases calcium absorption from food. Vitamin K2 activates proteins that direct that calcium into bones and teeth, keeping it out of your arteries and soft tissue. At standard doses (1000-2000 IU daily), most people get enough K2 from diet to handle the extra calcium. At 4000-5000 IU daily, the calcium load increases enough that K2 becomes a more serious consideration.

The Endocrine Society doesn't yet include K2 in its vitamin D guidelines. But a growing body of research, including a 2019 meta-analysis in International Journal of Molecular Sciences, shows the D3+K2 combination improves bone mineral density more than D3 alone.

If you eat K2-rich foods regularly (natto, hard cheese, egg yolks, chicken liver), a standalone D3 product like NOW Foods D3 5000 IU 360 Softgels (87/100) is a solid choice. If your diet is low in K2, or you're taking 4000+ IU of D3 daily, Thorne D + K2 covers both bases in one product.

Disclaimer: AIScored provides data-driven comparisons based on publicly available reviews. This is not medical advice. Affiliate links may earn us a commission at no extra cost to you.

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