NOW Foods Vitamin D-3 5,000 IU vs Nutravita Vitamin D3

Q: Which is better, NOW Foods Vitamin D-3 5,000 IU or Nutravita Vitamin D3?

NOW Foods Vitamin D-3 5,000 IU scores 82/100 while Nutravita Vitamin D3 scores 80/100 in our analysis. NOW Foods Vitamin D-3 5,000 IU is the higher-rated product overall.

Q: Is NOW Foods Vitamin D-3 5,000 IU worth the price compared to Nutravita Vitamin D3?

NOW Foods Vitamin D-3 5,000 IU scores 90.0/100 for value, while Nutravita Vitamin D3 scores 90.0/100. Both offer comparable value for money.

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

Of 35 vitamin D products in our database, only 1 carries third-party certification. That means 97% of the vitamin D supplements sold in the UK have no independent verification of what's actually in the bottle. UK regulations don't require third-party testing for supplements, so most brands skip it to save money. If certification matters to you, NOW Foods and Thorne are the brands scoring highest in our rankings, with overall scores of 85-87/100.

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

Our data shows that Thorne Vitamin D + K2 Liquid is the only combination D3+K2 product scoring 87/100 in our database of 35 vitamin D supplements, tying with two NOW Foods D3-only products for the top spot. Clinical research suggests K2 helps direct calcium to bones rather than arteries, which may matter at doses above 4000 IU daily. If you already eat K2-rich foods like natto, hard cheese, or egg yolks, a standalone D3 product may be sufficient.

Side-by-side comparison of scores, ingredients, prices and real customer feedback for NOW Foods Vitamin D-3 5,000 IU and Nutravita Vitamin D3.

Last verified: 28 Mar 2026 · Based on 67 reviews

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82.0

Score Summary

NOW Foods Vitamin D-3 5,000 IU scores 82.0/100 vs Nutravita Vitamin D3 at 80.0/100. NOW Foods Vitamin D-3 5,000 IU wins on effectiveness, ingredient quality. Nutravita Vitamin D3 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, ... NOW Foods	Nutravita Vitamin D3 4000 i... Nutravita
Overall Score	82.0	80.0
Effectiveness	86.0/100 Best	80.0/100
Ingredient Quality	83.0/100 Best	77.0/100
Value for Money	90.0/100 Best	90.0/100 Best
Side Effects	87.0/100	88.0/100 Best
Certifications	58.0/100	62.0/100 Best
Best Price	£6.74 iHerb → Cheapest	£8.99 Amazon UK →
Form	None	Softgel
Dose	None	116 Grams
Third-Party Tested	✗ No	✗ No
Reviews Analysed	50	17

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

Pros

✓D3 (cholecalciferol) in an olive oil and safflower oil base — the most bioavailable form, in the most appropriate delivery medium for a fat-soluble vitamin
✓Multiple reviewers confirmed blood test levels returning to normal after consistent use, including doctor-prescribed cases of significant deficiency
✓Small softgels praised consistently as easy to swallow, tasteless, and gentle on the stomach
✓5,000 IU therapeutic dose in a single capsule — practical for deficiency correction without splitting doses

Cons

✗Not third-party tested — no independent lab has verified potency or purity; specs confirm this
✗Not vegan or vegetarian: bovine gelatin capsule
✗5,000 IU exceeds standard maintenance levels and is not appropriate for unsupervised long-term use without periodic blood monitoring
✗Does not include K2, which several reviewers note is needed for proper calcium routing — requires a separate purchase

Best For

Adults with confirmed vitamin D deficiency, especially those prescribed 5,000 IU by a doctor People in low-sunlight climates or spending most of the year indoors Budget-conscious buyers wanting a clean single-ingredient D3 without unnecessary additives Those who already take a separate K2 supplement and want a standalone high-dose D3

iHerb £6.74

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 →

Score Breakdown: NOW Foods Vitamin D-3 5,000 IU vs Nutravita Vitamin D3

NOW Foods Vitamin D-3 5,000 IU Winner 82.0/100

5,000 IU of cholecalciferol per softgel puts this firmly in therapeutic territory — a dose multiple reviewers had validated by blood tests showing deficiency fully corrected.

Effectiveness

Vitamin D-3, Hig..

86.0/100

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..

90.0/100

Nutravita Vitami..

90.0/100

Side Effects

Vitamin D-3, Hig..

87.0/100

Nutravita Vitami..

88.0/100

Certifications

Vitamin D-3, Hig..

58.0/100

Nutravita Vitami..

62.0/100

What are the key differences?

NOW Foods Vitamin D-3 5,000 IU is best for: Adults with confirmed vitamin D deficiency, especially those prescribed 5,000 IU by a doctor, People in low-sunlight climates or spending most of the year indoors

Nutravita Vitamin D3 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, NOW Foods Vitamin D-3 5,000 IU or Nutravita Vitamin D3? ▼

NOW Foods Vitamin D-3 5,000 IU scores 82.0/100 overall while Nutravita Vitamin D3 scores 80.0/100. NOW Foods Vitamin D-3 5,000 IU comes out ahead, scoring higher on effectiveness (86.0 vs 80.0). NOW Foods Vitamin D-3 5,000 IU is best suited for Adults with confirmed vitamin D deficiency, especially those prescribed 5,000 IU by a doctor and People in low-sunlight climates or spending most of the year indoors. Nutravita Vitamin D3 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 NOW Foods Vitamin D-3 5,000 IU worth the price compared to Nutravita Vitamin D3? ▼

NOW Foods Vitamin D-3 5,000 IU costs £6.74 while Nutravita Vitamin D3 is £8.99. For value, NOW Foods Vitamin D-3 5,000 IU scores 90.0/100 vs Nutravita Vitamin D3's 90.0/100. Both offer similar value for money.

Which has fewer side effects? ▼

NOW Foods Vitamin D-3 5,000 IU scores 87.0/100 for side effects (higher means fewer reported issues) while Nutravita Vitamin D3 scores 88.0/100. Reviewers report fewer side effects with Nutravita Vitamin D3. For certification and testing, NOW Foods Vitamin D-3 5,000 IU scores 58.0/100 vs Nutravita Vitamin D3's 62.0/100. Always consult a healthcare professional before starting any supplement.

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Vitamin D-3, High Potency, 2,000 IU, 240 Softgels

vs Vitamin D-3, High Potency, 5,000 IU, 120 Softgels

Vitamin D-3, High Potency, 2,000 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

View all Vitamin D comparisons →

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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