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Protein WorksVitamins

Vitamin D3 + K2 360 Brand New, 360 tablets

£17.99 for 360 tablets at Protein Works. That works out at 1p per 1,000 IU, which ranks it 12th of the 207 vitamin D3 products we price across 20 UK retailers.

What it really costs, per 1,000 IU1pOne 1,000 IU dose is our comparison unit for vitamin D3. It is not a recommendation.
A day1p
A week9p
A month37p
A year£4.56

At one 1,000 IU dose a day, this pack lasts 3.9 years. A month is 30 days, so twelve of them is not quite a year.

How we worked it out

Vitamin D3

  • Servings: 360 ÷ 1 per serving = 360
  • In the pack: 360 × 4,000 IU = 1,440,000 IU
  • £17.99 ÷ 1,440,000 IU × 1,000 IU = 1.25p per 1,000 IU
  • A week 1.25p × 7 = 9p · a month × 30 = 37p · a year × 365 = £4.56
  • Amount per serving: stated on the label.

Vitamin K2

  • Servings: 360 ÷ 1 per serving = 360
  • In the pack: 360 × 100 µg = 36 mg
  • £17.99 ÷ 36 mg × 100 µg = 5p per 100 µg
  • A week 5p × 7 = 35p · a month × 30 = £1.50 · a year × 365 = £18.24
  • Amount per serving: stated on the label.

The standard dose is a comparison unit, not a recommendation. Always confirm the price on the retailer's site. How we compare everything.

Cheaper vitamin D3

All 207, ranked →
Vitamin D3 Tablets 4,000iuSimply Supplements · 4,000 IU a serving · 29p a month · a pack lasts 3.9 years1p£13.99View at Simply Supplements (opens in a new tab)
Vitamin D-3 5,000 IUHealf · 5,000 IU a serving · 30p a month · a pack lasts 3.3 years1p£11.81View at Healf (opens in a new tab)
Vitamin D3 + K2 540 Brand NewProtein Works · 4,000 IU a serving · 33p a month · a pack lasts 5.9 years1p£23.99View at Protein Works (opens in a new tab)
VitaBrightVitamin D3 4000IUVitaBright · 4,000 IU a serving · 35p a month · a pack lasts 4.7 years1p£19.99View at VitaBright (opens in a new tab)
VitaBrightVitamin D3 TabletsVitaBright · 4,000 IU a serving · 35p a month · a pack lasts 4.7 years1p£19.99View at VitaBright (opens in a new tab)
This productProtein Works · 4,000 IU a serving · 37p a month · a pack lasts 3.9 years1pshown above

Switching to the Simply Supplements pack saves 8p a month at the same 1,000 IU dose.

Ranked purely by price per 1,000 IU. 439 combination products also contain vitamin D3.

Cheaper vitamin K2 MK-7

All 68, ranked →
ZipVitVitamin D3 & K2ZipVit · 100 µg a serving · 82p a month · a pack lasts 1 year3p£9.99View at ZipVit (opens in a new tab)
ZipVitVitamin K2 MK-7 200mcgZipVit · 200 µg a serving · £1.25 a month · a pack lasts 12 months4p£14.99View at ZipVit (opens in a new tab)
Vitamin K2 TabletsBulk · 75 µg a serving · £1.33 a month · a pack lasts 2 months4p£2.99View at Bulk (opens in a new tab)
ZipVitVitamin K2 MK-7 200mcgZipVit · 200 µg a serving · £1.33 a month · a pack lasts 6 months4p£7.99View at ZipVit (opens in a new tab)
Vitamin D3 + K2 540 Brand NewProtein Works · 100 µg a serving · £1.33 a month · a pack lasts 1.5 years4p£23.99View at Protein Works (opens in a new tab)
This productProtein Works · 100 µg a serving · £1.50 a month · a pack lasts 12 months5pshown above

Switching to the ZipVit pack saves 68p a month at the same 100 µg dose.

Ranked purely by price per 100 µg. 52 combination products also contain vitamin K2.

On the label

Vitamin D3 · Vitamin D3
4,000 IU per serving (stated on the label)
Vitamin K2 · MK-7
100 µg per serving (stated on the label)
Pack
360 tablets · 360 servings · 1 tablet(s) a serving
Cost per serving
5p (360 servings in the pack)
More label details
Barcode
5061062525608
Sold by
Protein Works
What the listing says
“Per 1 Tablet” · “[Vitamin D3 ; 100µg ; 2000%]” · “confirmed from the retailer's own product page, not this listing's text: form id d3; amount per serving 100.0; amount unit mcg; amount refers to elemental; units per serving 1.0; pack units 360; pack unit type tablet”
Ingredients

Microcrystalline Cellulose, Vitamin D3 (Cholecalciferol), Vitamin K2 Menaquinone-7, Anti-Caking Agent (Magnesium Stearate).

From the Protein Works listing. Check the pack itself if you have an allergy: labels mark allergens in bold.

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One 1,000 IU dose is our comparison unit, not a recommendation.

Price history

No price change since 23 September 2026. Checked on 2 days, most recently 9 October 2026.

Price at every check
£17.99Protein Works
First recorded
£17.9923 Sept
Checked on
2 dayssince 23 Sept
Pack price at each check.
  1. First checked at Protein Works: £17.99

Questions about this product

How much does Protein Works Vitamin D3 + K2 360 Brand New cost per 1,000 IU?

1p per 1,000 IU, from £17.99 for 360 tablets at Protein Works, checked on 9 October 2026.

Is it the cheapest vitamin D3 in the UK?

No, it is 12th of 207. High-Strength Vitamin D3 Tablets at WeightWorld works out at 1p per 1,000 IU.

How long does one pack last?

3.9 years at one 1,000 IU dose. The pack holds 1,440,000 IU in total.

How much does Protein Works Vitamin D3 + K2 360 Brand New cost per 100 µg?

5p per 100 µg, from £17.99 for 360 tablets at Protein Works, checked on 9 October 2026.

Is it the cheapest vitamin K2 MK-7 in the UK?

No, it is 10th of 68. Vitamin D3 2000IU + K2 (MK-7) Tablets at WeightWorld works out at 2p per 100 µg.

How long does one pack last?

12 months at one 100 µg dose. The pack holds 36 mg in total.

About Protein Works

Founded 2012 · Liverpool, England · Part of Lactalis

Protein Works is a British nutrition company founded in 2012 by Mark Coxhead, Nick Smith and Karl Jacobie. It is based at PW Campus in Speke, Liverpool, which opened in 2025 and replaced several sites in Runcorn.

All 149 Protein Works products, priced per doseVisit Protein Works (opens in a new tab)

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