Vitamin D3 1000 IU, 365 Tablets
by Bulk
Compare Prices
Bulk's Vitamin D3 1000 IU offers a full year's supply of cholecalciferol at the NHS-recommended daily dose, making it one of the most cost-effective options in the UK market. Best for UK residents seeking winter/year-round maintenance supplementation and Budget-conscious buyers wanting a no-frills daily supplement.
According to the AIScored 0–100 scoring system, Vitamin D3 1000 IU, 365 Tablets by Bulk scores 72.0/100, ranking #32 out of 35 products in Vitamin D (2026). Strongest category: Side Effects (93.0/100). Weakest: Certifications (28.0/100).
Is Vitamin D3 1000 IU, 365 Tablets worth buying?
“Bulk's Vitamin D3 is exceptional value at the NHS-recommended 1000 IU dose—365 tablets work out incredibly cheap per day, which is why it scores 72/100 despite being no-frills. The tablets are small and tasteless enough to take daily without thinking about them, and you're getting D3 rather than inferior D2.”
What Do Reviewers Say About Vitamin D3 1000 IU, 365 Tablets?
Sample excerpts from currently available source material used in this product analysis.
"Good value. Living in the North of England we do not get the same sun as other parts of the country, so we take these over the winter months, to ensure we are getting the amount of vitamin D we need. Buying this big bottle is so cost effect..."
"Vitamin D3 tablets. Good price, small tablets easy to swallow. Brings lots of benefits taking these supplements all year round."
"Great quality and an affordable price. I've been using vitamins from Bulk Powders for years and always find their quality and price perfect for my needs. Vitamin D is one of those vitamins we tend to be deficient in as we get older. We also..."
"Great value for quantity. Really great value for money with so many tablets in the container. I've read that some were unhappy with the large container as it is a waste and unnecessary. I do understand their point, but I think the brand was..."
"Important to get D3 and this is great value. With this current Covid-19 situation I was recommended to take Vitamin D3, so looked on Amazon and they had a deal great product great price."
How does Vitamin D3 1000 IU, 365 Tablets score?
Detailed score breakdown and key findings from our analysis of 15 reviews across 1 source.
Pros
- +Outstanding value — 365-tablet year supply at very low per-tablet cost
- +Small, tasteless tablets universally described as easy to swallow
- +Cholecalciferol (D3) is the superior, well-researched form vs D2
- +Matches NHS recommended daily amount — appropriate for general maintenance
- +Bulk is an established, reputable UK supplement brand with loyal long-term customers
Cons
- -Not vegan — D3 sourced from lanolin (animal-derived)
- -No third-party testing or quality certifications (e.g. Informed Sport)
- -1000 IU may be insufficient for people with confirmed deficiency (clinical doses are typically 2000–4000 IU)
- -Isolated Amazon fulfillment complaints: near-expiry stock and potentially tampered packaging reported
Best For
Watch Out
- !Check expiry date on arrival — at least one reviewer received stock expiring within 2 months
- !Inspect packaging seal — one report of compromised Amazon fulfillment
- !1000 IU is a maintenance dose only; get blood levels tested if deficiency is suspected and consider a higher-dose product
- !Not suitable for vegans — contains animal-derived D3
What is Vitamin D3 1000 IU, 365 Tablets?
Vitamin D3 1000 IU, 365 Tablets is a vitamin d product by Bulk in tablet form, scoring 72.0/100 on AIScored.
- • Bulk Vitamin D3 provides 1000 IU (25mcg) of Vitamin D3 per tablet for a full year supply.
- • Vitamin D contributes to normal immune function, supports the maintenance of normal bones, teeth, and muscle function.
- • One of the most affordable Vitamin D supplements available, with each tablet providing the NHS recommended daily amount.
- • Easy to swallow tablets.
What's Inside Vitamin D3 1000 IU, 365 Tablets?
Vitamin D3 1000 IU, 365 Tablets contains 1 active ingredient: Vitamin D3 (as Cholecalciferol).
Active Ingredients
- Vitamin D3 (as Cholecalciferol)
- 25mcg (1000 IU)
Is Vitamin D3 1000 IU, 365 Tablets Independently Tested?
No Third-Party Testing Visible
We could not find evidence of independent third-party testing for this product. This doesn't mean it's unsafe, but independent verification provides additional assurance.
How We Score Supplements
Our methodology analyses review data, ingredient science, and product information, then scores each product on a 0-100 scale across evidence-based categories:
Effectiveness
How well the product delivers its claimed benefits, based on reviews and ingredient evidence.
Ingredient Quality
Bioavailable forms, clinically effective dosages, clean label, minimal fillers.
Value for Money
Price relative to ingredient quality, dosage count, and effectiveness.
Side Effects Profile
Higher score = fewer side effects. 100 means virtually no adverse reactions reported.
Certifications & Testing
Third-party lab testing, GMP certification, and independent quality verification.
Overall Score
Weighted combination of all factors. Our bottom-line recommendation.
Price History (90 days)
Quick Facts
- Form
- Tablet
- Dose
- 1000 IU (25mcg)
- Serving
- 1 tablet
- Servings
- 365
- Vegan
- No
Frequently Asked Questions
Is Vitamin D3 1000 IU, 365 Tablets worth buying in 2026? ▼
What is the best price for Vitamin D3 1000 IU, 365 Tablets in the UK? ▼
What are the pros and cons of Vitamin D3 1000 IU, 365 Tablets? ▼
Is Vitamin D3 1000 IU, 365 Tablets third-party tested? ▼
What the Data Says About Vitamin D
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 research-backed summaries based on publicly available reviews and product information. This is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Affiliate links may earn us a commission at no extra cost to you.
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