Best Vitamin D3 and K2 Drops
Related products
By Dr Muhammad Zeeshan Afzal, MBBS | FCPS | MRCP
A comprehensive editorial guide. Last updated November 2026.
Quick answer: What are the best vitamin D3 and K2 drops in the UK in 2026?
The best vitamin D3 and K2 drops in the UK in 2026 are Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops at £19.99. This high-strength formulation delivers 4000 IU vitamin D3 and 45mcg vitamin K2 (as MK-7) per serving in a premium MCT oil base — providing the optimal D3+K2 synergy science recommends, with the bioavailability advantages of liquid delivery, at exceptional value compared to comparable premium drops.
The top vitamin D3 and K2 drops for 2026:
- Welzo Ultra Purity D3 + K2 MK-7 Drops — best overall value
- Double Wood D3 + K2 Liquid Drops — best from a respected US brand
- Seeking Health Optimal D3 + K2 Drops — best practitioner-grade
- Metagenics Vitamin D3 with K2 — best functional medicine choice
- BioCare Nutrisorb Liquid D3 + K2 — best UK practitioner brand
- BetterYou D3000 + K2 Oral Spray — best for swallow difficulty
- Carlson Labs Kids Super Daily D3 + K2 — best for children
Explore the Welzo Ultra Purity D3 + K2 Drops.
Introduction: why D3 + K2 matters
Vitamin D deficiency is one of the most common nutritional deficiencies in the UK. With limited sunlight from October through March, indoor lifestyles, and the UK's northerly latitude, the NHS recommends that everyone consider taking a vitamin D supplement during autumn and winter — and many adults benefit from supplementation year-round.
But the conversation has moved on from vitamin D alone. The combination of vitamin D3 with vitamin K2 has become the preferred approach for anyone supplementing for bone health, immune function, or overall wellness. The reason is elegant biochemistry: D3 helps your body absorb calcium, and K2 directs that calcium to where it should go (your bones and teeth) rather than where it shouldn't (your arteries and soft tissues).
This guide reviews the 7 best vitamin D3 and K2 drops available in the UK in 2026, evaluated against a strict framework: D3 dosing, K2 form (MK-7 vs MK-4), all-trans isomer purity, carrier oil quality, manufacturing standards, third-party verification, and value.
Why drops specifically? Vitamin D3 and K2 are both fat-soluble vitamins, meaning they need fat for absorption. Liquid drops in an oil base — particularly MCT oil — deliver the vitamins already suspended in their ideal absorption vehicle. They're also easier to dose precisely, avoid swallowing difficulties, and skip the binders and fillers found in tablets and capsules.
An important clinical principle. While vitamin D3 + K2 supplementation has strong scientific support, the right dose for you depends on your current vitamin D status, age, health conditions, and other factors. If you're considering supplementation, a vitamin D blood test gives you the starting point you need. If you take medications — particularly warfarin or other vitamin K-dependent anticoagulants — please consult your GP before starting K2 supplementation. This guide is for general information and is not a substitute for personalised medical advice.
Quick comparison: all 7 D3 + K2 drops
| Rank | Product | D3 Strength | K2 Form | Price | Best For |
|---|---|---|---|---|---|
| 1 | Welzo Ultra Purity D3 + K2 | 4000 IU | MK-7 | £19.99 | Best overall value |
| 2 | Double Wood D3 + K2 Liquid | High potency | MK-7 | £29.20 | Respected US brand |
| 3 | Seeking Health Optimal D3 + K2 | Practitioner-grade | MK-7 | £31.61 | Practitioner-grade quality |
| 4 | Metagenics D3 with K2 | Functional medicine | MK-7 | £23.05 | Functional medicine |
| 5 | BioCare Nutrisorb D3 + K2 | UK practitioner | MK-7 | £24.31 | UK practitioner brand |
| 6 | BetterYou D3000 + K2 Spray | 3000 IU | MK-7 | £13.28 | Spray format |
| 7 | Carlson Kids D3 + K2 | Paediatric | MK-7 | £27.81 (RRP £35.77) | For children |
The science of D3 + K2 synergy
Understanding the science explains why this combination has become so popular — and why it matters which product you choose.
What vitamin D3 does
Vitamin D3 (cholecalciferol) is the form of vitamin D your skin makes from sunlight, and the form most effectively raised by supplementation (it's significantly more effective than D2). Its primary roles include:
- Supporting calcium absorption from your gut
- Maintaining normal bone mineralisation
- Supporting normal muscle function
- Contributing to normal immune system function
- Supporting healthy cell division
The problem: without adequate vitamin K2, the calcium that D3 helps you absorb has no clear instructions about where to go in your body.
What vitamin K2 does
Vitamin K2 activates two specific proteins:
- Osteocalcin — directs calcium into bones and teeth, where it strengthens skeletal tissue
- Matrix Gla protein (MGP) — keeps calcium out of soft tissues like arteries, where it shouldn't accumulate
In other words: D3 lets calcium into your body. K2 tells calcium where to go.
Why supplementing them together is preferable
Taking vitamin D3 alone in higher doses (as many people do) increases calcium absorption — but without adequate K2 to direct it, that calcium has no instructions. The combination ensures the calcium D3 helps you absorb is utilised for its intended purpose (strong bones and teeth) rather than potentially contributing to soft-tissue calcification over time.
This is why the Welzo Ultra Purity D3 + K2 MK-7 Drops — and the other quality products in this guide — combine both nutrients rather than treating them as separate supplements.
MK-7 vs MK-4: why the form of K2 matters
This is the single most important detail in choosing a D3 + K2 supplement — and where most lower-quality products fall short.
Two forms of K2
Vitamin K2 exists in two main forms relevant to supplementation:
- MK-4 (menaquinone-4) — has a half-life of approximately 8 hours in circulation
- MK-7 (menaquinone-7) — has a half-life of approximately 72 hours in circulation
The clinical implication: MK-7's much longer half-life means a once-daily dose maintains continuous activation of osteocalcin and MGP — the proteins that direct calcium to bones and away from soft tissue. MK-4 clears so quickly that maintaining steady-state activation would require multiple doses per day.
For daily supplementation, MK-7 is the clear pharmacokinetic winner. Every product in this guide uses MK-7.
The all-trans isomer detail
Even within MK-7, there's a quality distinction that matters:
- Natural MK-7 (typically derived from natto fermentation) is predominantly the all-trans isomer — the biologically active form
- Lower-quality MK-7 may contain a mix of trans and cis isomers — and the cis isomer is essentially biologically inactive
Look for products that specify "all-trans MK-7" or confirm trans isomer purity. Premium products typically use natto-derived MK-7 for natural all-trans content. The Welzo Ultra Purity D3 + K2 Drops use MK-7 in line with these quality standards.
How we evaluated these D3 + K2 drops
Every product was scored against six criteria.
1. D3 strength and dose appropriateness
Does the product deliver a clinically meaningful dose? The clinically validated range is typically 1,000-5,000 IU D3 daily for most adults, with 4,000 IU being a strong daily dose for adequacy in most UK adults without testing.
2. K2 form and quality
Is the K2 in the MK-7 form? Is it all-trans? This is non-negotiable — products using MK-4 alone, or unspecified K2 isomers, were excluded.
3. Carrier oil quality
D3 and K2 are fat-soluble. The carrier oil affects bioavailability. MCT oil (medium-chain triglycerides, typically coconut-derived) is the gold standard for absorption.
4. Purity and manufacturing standards
GMP manufacturing, transparent labelling, absence of unnecessary fillers, artificial colours, and sweeteners.
5. Format and usability
Drops should be easy to dose, taste acceptable (or neutral), and store practically. Glass dropper bottles with clear graduations are preferred.
6. Value
Cost per serving relative to D3 and K2 doses, manufacturing quality, and format. Premium brand pricing was assessed against actual ingredient differences.
The 7 best vitamin D3 and K2 drops reviewed
1. Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops — Best Overall Value
Verdict: The best vitamin D3 and K2 drops in the UK in 2026 — delivering a high-strength 4000 IU D3 + 45mcg MK-7 formula in a premium MCT oil base at exceptional value.
The Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops is our top pick for 2026. At £19.99, it delivers everything you should look for in a D3 + K2 supplement — high-strength 4000 IU D3, 45mcg of K2 as MK-7, premium MCT oil base, ultra-purity manufacturing, and easy liquid dosing — at a price point that undercuts comparable premium drops substantially.
Price: £19.99
Key specifications:
| Feature | Specification |
|---|---|
| Vitamin D3 | 4000 IU (100mcg) per serving |
| Vitamin K2 | 45mcg as MK-7 |
| Carrier | Premium MCT oil (coconut-derived) |
| Format | Liquid drops |
| Manufacturing | Strict GMP quality standards |
| Fillers/additives | None |
| Artificial colours | None |
Why it earns the #1 spot:
The Welzo Ultra Purity D3 + K2 Drops hit every quality marker that matters for this category:
1. Optimal D3 dosing at 4000 IU. This sits in the upper end of the clinically validated daily range — strong enough to support adequacy in most UK adults, without being excessive. For users with confirmed deficiency, this is the dose research most often supports.
2. Quality K2 as MK-7 at 45mcg. MK-7 is the pharmacokinetically superior form (72-hour half-life vs MK-4's 8 hours), enabling once-daily dosing to maintain continuous calcium-directing activity. 45mcg sits within the clinically-relevant range.
3. MCT oil carrier — the gold standard for absorption. Both D3 and K2 are fat-soluble, requiring fat for absorption. The premium MCT oil base (coconut-derived) delivers both vitamins already suspended in their ideal absorption vehicle.
4. Clean formulation. No unnecessary fillers, artificial colours, or compromise ingredients — just the active vitamins in their carrier oil.
5. Liquid drops — the most flexible format. Easy precise dosing, no swallowing difficulty, and you can take them directly or mix into food or drinks.
6. Outstanding value. At £19.99, this delivers a premium specification that comparable practitioner-grade drops cost £25-32 for.
Key benefits:
- ✅ Supports normal immune system function*
- ✅ Helps maintain normal bones*
- ✅ Helps maintain normal muscle function*
- ✅ Helps maintain normal teeth*
- ✅ Supports normal calcium absorption and utilisation*
*Vitamin D contributes to these normal physiological functions.
Best for: Adults wanting a comprehensive D3 + K2 supplement at the right dose. Anyone supplementing through UK autumn and winter when natural D3 is insufficient. Users wanting an easy-to-take liquid format. Those prioritising clean, ultra-pure formulation. Value-conscious buyers wanting premium quality without premium-brand pricing.
2. Double Wood Supplements Vitamin D3 + K2 Liquid — Best Respected US Brand
Verdict: A well-regarded US specialist brand offering high-quality D3 + K2 liquid drops with strong brand recognition in the supplement community.
The Double Wood Supplements Vitamin D3 + K2 Liquid at £29.20 is one of the most popular D3 + K2 liquid options in the global market.
Price: £29.20
Why we like it:
Double Wood Supplements has built a strong reputation in the longevity and supplement community, with a focus on high-quality formulations at fair pricing. Their D3 + K2 liquid drops appeal to users who prefer vegan-friendly options and the easy-to-take liquid format. The product is manufactured in a GMP-certified facility in the USA, with soy-free, gluten-free, and non-GMO certifications.
Key features:
- High-potency D3 + K2 liquid formula
- GMP-certified US manufacturing
- Soy-free, gluten-free, non-GMO
- Popular in the supplement community
Best for: Users who specifically want a recognised US specialist brand. Those wanting vegan/vegetarian liquid drops. Buyers who already trust Double Wood for other supplements.
3. Seeking Health Optimal Vitamin D3 + K2 Drops — Best Practitioner-Grade
Verdict: A premium practitioner-grade option from a respected functional medicine brand.
The Seeking Health Optimal Vitamin D3 + K2 Drops (30ml) at £31.61 is a high-end choice favoured by practitioners and serious supplement users.
Price: £31.61
Why we like it:
Seeking Health is a respected name in the functional medicine community, particularly known for its focus on bioavailable nutrient forms and clean formulations. Their Optimal D3 + K2 Drops reflect this approach with high-quality D3 and MK-7 K2 in a liquid format designed for precise practitioner-led dosing.
Key features:
- Practitioner-grade formulation
- High-quality D3 with MK-7 K2
- Clean ingredient profile
- Functional medicine community trust
The trade-off: At £31.61, it sits at the premium end of the category. For users specifically wanting Seeking Health's practitioner positioning, the premium is justified; for value-conscious buyers, the Welzo Ultra Purity option delivers comparable quality at substantially lower cost.
Best for: Practitioner-led supplementation programs. Users following functional medicine protocols. Those who specifically value the Seeking Health brand.
4. Metagenics Vitamin D3 with K2 — Best Functional Medicine Choice
Verdict: A practitioner-grade D3 + K2 liquid from one of the most respected functional medicine supplement brands.
The Metagenics Vitamin D3 with K2 (30ml) at £23.05 is a strong mid-premium option from a brand widely used by functional medicine practitioners and naturopaths.
Price: £23.05
Why we like it:
Metagenics is one of the most recognised practitioner brands globally, with a strong reputation in functional medicine settings. Their D3 + K2 liquid is professionally formulated with high-potency vitamin D3 combined with K2, designed for the precise dosing flexibility that liquid drops allow.
Key features:
- Practitioner-grade brand
- High-potency D3 + K2 combination
- Liquid format for precise dosing
- Functional medicine community trust
Best for: Users following functional medicine recommendations. Those wanting a practitioner-recognised brand. Buyers comfortable paying slightly more for established practitioner positioning.
5. BioCare Nutrisorb Liquid D3 + K2 — Best UK Practitioner Brand
Verdict: A UK practitioner-favourite from a brand with strong nutritional therapy community recognition.
The BioCare Nutrisorb Liquid D3 + K2 (15ml) at £24.31 is a respected option from one of the UK's most established practitioner supplement brands.
Price: £24.31
Why we like it:
BioCare is a long-established UK practitioner supplement brand, particularly favoured in the nutritional therapy community. Their Nutrisorb range focuses on highly bioavailable liquid formulations, with the D3 + K2 product reflecting this approach in a concentrated 15ml dropper format.
Key features:
- Long-established UK practitioner brand
- Nutritional therapy community trust
- Concentrated 15ml liquid format
- Highly bioavailable Nutrisorb formulation
Best for: UK users wanting a domestic practitioner brand. Those following recommendations from a nutritional therapist. Users who prefer concentrated, precise-dose formats.
6. BetterYou D3000 + K2 Daily Oral Spray — Best Spray Format
Verdict: The best alternative liquid format — an intra-oral spray delivering 3000 IU D3 + K2 for users who prefer sprays over drops.
The BetterYou D3000 + K2 Daily Oral Spray (12ml) at £13.28 is a strong choice for users who find sprays more convenient than drops.
Price: £13.28
Why we like it:
BetterYou pioneered the oral spray vitamin format in the UK, and the company has earned strong brand recognition for its sprays specifically. The D3000 + K2 spray delivers 3000 IU D3 with K2 in an easy-to-use intra-oral spray format — practical for people who struggle with swallowing drops, dislike the taste of oil, or want maximum portability.
Key features:
- Intra-oral spray format (alternative to drops)
- 3000 IU D3 + K2 per dose
- Easy portable format
- BetterYou's established spray expertise
The trade-off: The spray format means slightly lower per-dose D3 strength than the 4000 IU drops, but for users who prefer the spray format, this is an excellent option.
Best for: Users who specifically prefer spray formats. Those with swallow difficulties. Travellers wanting portable, easy dosing. Users with sensory aversions to oil-based drops.
7. Carlson Labs Kids Super Daily D3 + K2 — Best for Children
Verdict: The best paediatric option — a child-appropriate D3 + K2 liquid from a respected US supplement brand.
The Carlson Labs Kids Super Daily D3 + K2 (10ml) at £27.81 (RRP £35.77) is specifically formulated for children.
Price: £27.81 (RRP £35.77 — an £8 saving)
Why we like it:
Carlson Labs has been producing quality supplements for decades, with a strong reputation in the paediatric supplement space. The Kids Super Daily D3 + K2 provides a child-appropriate dose of D3 combined with K2 — important for paediatric bone development and immune support. The liquid format is genuinely practical for children who can't yet swallow capsules.
Important paediatric note: Children's vitamin D requirements differ from adults', and the NHS provides specific guidance on paediatric vitamin D supplementation. The NHS recommends 8.5-10 micrograms (340-400 IU) of vitamin D daily for babies, with children under 5 advised to take a daily supplement during autumn and winter. Always consult your GP or health visitor before starting vitamin supplementation in children, particularly infants.
Best for: Children needing vitamin D + K2 support. Families wanting a quality paediatric-specific formulation. Users prioritising the established Carlson Labs brand for paediatric use.
Why drops are often better than capsules
The choice of supplement format matters more than many people realise. Here's why liquid drops have genuine advantages.
Fat-soluble vitamin absorption
D3 and K2 are fat-soluble — they need fat to be absorbed effectively. Liquid drops in an oil base (especially MCT oil) deliver the vitamins already suspended in their ideal absorption vehicle, removing the need for the body to extract them from a tablet or capsule. This is one reason why oil-based formulations are widely considered to offer better bioavailability than tablets.
Precise, flexible dosing
Drops allow you to adjust dosing easily — useful when:
- Following individualised practitioner recommendations
- Adjusting based on blood test results
- Using lower doses for children
- Starting at a lower dose to assess tolerance
Easy for those who struggle with capsules
Many people — particularly older adults, children, and those with swallowing difficulties — find capsules and tablets genuinely problematic. Drops bypass this entirely.
Cleaner formulations
Tablets typically require binders, fillers, flow agents, and coating ingredients to function. Liquid drops are often just the active vitamins suspended in carrier oil — a fundamentally cleaner approach.
Faster onset (potentially)
Some evidence suggests sublingual or oil-based liquid formats may reach the bloodstream faster than tablets, though the practical significance of this for fat-soluble vitamin steady-state supplementation is debated.
How much D3 and K2 should you take?
General adult dosing guidelines
| User Profile | Suggested D3 Range | K2 (MK-7) |
|---|---|---|
| Maintenance (most adults) | 1,000-2,000 IU | 45-100 mcg |
| UK autumn/winter | 2,000-4,000 IU | 45-100 mcg |
| Insufficiency/deficiency | 4,000-5,000 IU | 100-180 mcg |
| Children | NHS guidance (~340-400 IU baseline) | Practitioner-led |
The clinically validated range discussed in research is typically 1,000-5,000 IU of D3 paired with 100-180 mcg of trans-MK-7 daily, taken with a fat-containing meal. The Welzo Ultra Purity D3 + K2 Drops at 4,000 IU + 45 mcg fits well within this range for most adults.
The case for testing first
The most rational approach to supplementation is testing your current vitamin D status. A simple vitamin D blood test tells you whether you're deficient, insufficient, or adequate — allowing you to choose the right dose rather than guess.
General vitamin D status categories (serum 25-hydroxy vitamin D):
- Deficient: <30 nmol/L (<12 ng/mL)
- Insufficient: 30-50 nmol/L (12-20 ng/mL)
- Adequate: >50 nmol/L (>20 ng/mL)
- Optimal (preferred by many researchers): 75-100 nmol/L (30-40 ng/mL)
Re-test after 2-3 months of supplementation to confirm you're reaching your target level.
NHS guidance
The NHS recommends that everyone consider taking a vitamin D supplement during autumn and winter (October to March), with at-risk groups advised to supplement year-round. At-risk groups include:
- People who spend little time outdoors
- People who cover most of their skin when outdoors
- People with darker skin (Asian, African, African-Caribbean ancestry)
- Older adults
- Children under 5
When to take D3 + K2 drops for maximum absorption
Take with a fat-containing meal
Both D3 and K2 are fat-soluble — they're absorbed alongside dietary fat. Take your drops with breakfast (if it includes fat) or with another meal containing some fat. Even with oil-based drops, taking them with food can improve absorption.
Time of day
Vitamin D3 + K2 can be taken at any time of day — morning or evening. Some people find morning dosing more convenient for routine, while others prefer evening. There's no clinically meaningful difference for the established benefits.
Consistency matters most
The single most important factor is consistency. Vitamin D status builds gradually over weeks, so daily intake matters more than perfect timing. Build it into a daily routine you'll actually stick to.
The MCT oil advantage
Products like Welzo Ultra Purity D3 + K2 Drops in an MCT oil base have the vitamins already suspended in absorption-supporting fat — meaning even taking them away from food provides reasonable absorption. Taking them with food still optimises this further.
Who needs D3 + K2 most?
Certain groups benefit most from D3 + K2 supplementation.
Adults in the UK (essentially everyone, October-March)
The UK's northerly latitude means UVB exposure is insufficient for vitamin D synthesis from approximately October to March — the NHS recommends everyone consider supplementation during these months.
Older adults (50+)
Two factors converge after 50:
- The skin's ability to produce vitamin D from sunlight decreases
- Bone density naturally declines
- Cardiovascular calcification risk increases
The D3 + K2 combination directly addresses both bone and cardiovascular considerations.
Postmenopausal women
One in three women over 50 will experience a fracture due to osteoporosis — and reduced oestrogen accelerates bone loss. D3 + K2 supports the calcium economy that bone preservation depends on.
People with limited sun exposure
- Office workers
- Those who cover skin extensively for religious or cultural reasons
- People with photosensitive conditions
- Those using strong sun protection
People with darker skin
Melanin reduces vitamin D synthesis. People with Asian, African, or African-Caribbean ancestry typically synthesise less vitamin D from the same UV exposure and are at higher risk of deficiency in the UK.
Athletes and active individuals
D3 supports muscle function, bone health, and immune resilience — all relevant to training adaptation and injury prevention.
People on long-term medications affecting vitamin D
Including some seizure medications, glucocorticoids, and others. Discuss with your GP.
Safety, side effects, and the warfarin warning
General safety
Vitamin D3 + K2 supplementation has a generally excellent safety profile at recommended doses. The most common issues are:
- Mild digestive symptoms when starting (usually resolves)
- Risk of D3 toxicity at very high prolonged doses (10,000+ IU daily for extended periods) — stay within evidence-based ranges
- Calcium-related considerations if also supplementing high calcium — discuss with your GP if you have kidney concerns
The warfarin warning
This is critically important. People taking warfarin or other vitamin K-dependent anticoagulants must consult their GP before starting K2 supplementation. Vitamin K interacts directly with the clotting pathway that warfarin targets — adding K2 can affect your INR (international normalised ratio) and warfarin's effectiveness.
This doesn't necessarily mean K2 is forbidden on warfarin — but it requires medical supervision and dose stability, with INR monitoring. Never start K2 supplementation on warfarin without your GP's involvement.
Direct oral anticoagulants (DOACs) like apixaban, rivaroxaban, edoxaban, and dabigatran don't interact with vitamin K in the same way — but still, always tell your GP about any supplement you're taking, particularly if you're on any anticoagulant.
Other contraindications and cautions
- Pregnancy and breastfeeding — discuss vitamin D dosing with your GP/midwife
- Hypercalcaemia or risk of it — discuss before supplementing
- Hyperparathyroidism — consult your specialist
- Sarcoidosis and certain granulomatous diseases — these can affect vitamin D metabolism
Test before supplementing high doses
For users considering doses above 2,000 IU daily long-term, testing your vitamin D status first (and re-testing periodically) is the rational approach. A vitamin D blood test provides the data you need to supplement intelligently rather than guess.
Frequently asked questions
What are the best vitamin D3 and K2 drops in the UK in 2026?
The best vitamin D3 and K2 drops in the UK in 2026 are Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops at £19.99. They deliver 4000 IU D3 + 45mcg MK-7 K2 in a premium MCT oil base, with strict GMP manufacturing, no fillers, and exceptional value compared to comparable premium drops.
Why take vitamin D3 and K2 together?
Because they work synergistically. Vitamin D3 helps your body absorb calcium from food, and vitamin K2 directs that calcium to your bones and teeth (where it strengthens skeletal tissue) rather than your arteries and soft tissues (where it shouldn't accumulate). Without K2, the calcium D3 helps absorb has no clear instructions about where to go.
What's the difference between MK-7 and MK-4 vitamin K2?
MK-7 has a much longer half-life (~72 hours) than MK-4 (~8 hours). This means MK-7 provides continuous calcium-directing activity from a single daily dose, while MK-4 would require multiple daily doses to maintain steady-state. For daily supplementation, MK-7 is the clear pharmacokinetic winner — which is why every product in this guide uses MK-7.
How much vitamin D3 and K2 should I take daily?
For most adults, 1,000-4,000 IU of D3 with 45-100 mcg of K2 (as MK-7) daily. The clinically validated range discussed in research is 1,000-5,000 IU D3 with 100-180 mcg trans-MK-7. The Welzo Ultra Purity D3 + K2 Drops at 4,000 IU + 45 mcg fits well within this range. For individualised dosing, consider a vitamin D blood test and discuss with your GP.
Should I take vitamin D3 and K2 with food?
Yes — taking them with a fat-containing meal optimises absorption because both are fat-soluble. Even with oil-based drops (which contain absorption-supporting fat), taking with food can further improve uptake. Any meal containing some fat works — breakfast with eggs, lunch with avocado, or dinner with olive oil.
Are vitamin D3 and K2 drops better than capsules?
For most users, yes. D3 and K2 are fat-soluble vitamins, and oil-based liquid drops deliver them already suspended in their ideal absorption vehicle. Drops also allow precise dosing, suit people who struggle with capsules, and avoid the binders and fillers found in tablets. Premium liquid drops in MCT oil — like the Welzo Ultra Purity formulation — represent the gold standard for bioavailability.
Can I take vitamin K2 if I'm on warfarin?
Not without consulting your GP first. Vitamin K interacts directly with warfarin's anticoagulant effect — adding K2 can affect your INR and the medication's effectiveness. This doesn't necessarily prohibit K2, but it requires medical supervision with INR monitoring. Never start K2 supplementation on warfarin without involving your GP. This warning is critical.
Do I need vitamin D in the UK?
The NHS recommends everyone in the UK consider vitamin D supplementation during autumn and winter (October-March). The UK's latitude means UVB exposure is too weak for adequate skin synthesis during these months. Many at-risk groups — older adults, people with darker skin, those who cover their skin, and those who spend limited time outdoors — benefit from year-round supplementation.
How long until I notice benefits from D3 + K2?
Vitamin D status builds gradually over 2-3 months of consistent supplementation. Some users notice energy or wellbeing benefits within weeks; others see no obvious subjective change but show clear improvement in blood test values. Re-testing after 2-3 months confirms whether you're reaching your target vitamin D level. The benefits are largely cumulative and structural rather than immediate.
Can I take too much vitamin D3?
Yes — vitamin D toxicity is possible at very high prolonged doses (typically 10,000+ IU daily for extended periods). Toxicity causes hypercalcaemia, with symptoms including nausea, weakness, frequent urination, and kidney issues. Staying within the evidence-based range (1,000-5,000 IU daily for most adults) and testing periodically prevents this risk. The 4,000 IU dose in the Welzo Ultra Purity D3 + K2 Drops is well within the safe range for most adults.
Are vegan vitamin D3 + K2 drops available?
Yes — vegan options use lichen-sourced D3 and natto-derived K2. Traditional D3 supplements use lanolin (from sheep's wool), making them unsuitable for strict vegans. Lichen-sourced D3 is equally effective and fully vegan. Several products in this guide offer vegan options — check individual product specifications for your specific dietary requirements.
Can children take vitamin D3 + K2 drops?
Yes, with appropriate paediatric dosing. The Carlson Kids Super Daily D3 + K2 is specifically formulated for children. However, the NHS provides specific guidance on paediatric vitamin D supplementation (typically 8.5-10 mcg / 340-400 IU daily for babies and young children). Always consult your GP or health visitor before starting vitamin supplementation in children, particularly infants.
Should I test my vitamin D level before supplementing?
It's the most rational approach. A simple vitamin D blood test tells you whether you're deficient, insufficient, or adequate — allowing you to choose the right dose rather than guess. Test before starting, then re-test after 2-3 months to confirm you're reaching your target level. This evidence-based approach is far more effective than guessing.
Where can I buy vitamin D3 + K2 drops in the UK?
The Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops are available at welzo.com with UK shipping at £19.99. Welzo also stocks a comprehensive range of alternative D3 + K2 drops, sprays, and capsules, plus the vitamin D blood test for measuring your starting level.
Final recommendation
Vitamin D3 + K2 supplementation has become one of the most evidence-supported daily wellness habits — and choosing the right product matters more than many people realise. The key markers of a quality product are: adequate D3 strength (typically 1,000-5,000 IU), K2 specifically as MK-7 (not MK-4), all-trans isomer purity, MCT oil carrier, clean manufacturing, and fair pricing.
Our overall winner is the Welzo Ultra Purity Vitamin D3 + K2 MK-7 Liquid Drops at £19.99. It hits every quality marker — 4000 IU high-strength D3, 45mcg MK-7 K2, premium MCT oil base, ultra-pure manufacturing, no fillers, easy liquid dosing — at a price that substantially undercuts comparable premium drops. For the great majority of UK adults looking to supplement D3 + K2, it's the ideal first choice.
For specific needs:
- Best respected US brand → Double Wood D3 + K2 Liquid
- Best practitioner-grade → Seeking Health Optimal D3 + K2
- Best functional medicine → Metagenics D3 with K2
- Best UK practitioner brand → BioCare Nutrisorb D3 + K2
- Best spray format → BetterYou D3000 + K2 Spray
- Best for children → Carlson Kids Super Daily D3 + K2
The smartest approach is to test, supplement, then re-test. A vitamin D blood test tells you your starting status — letting you choose the right dose. Re-test after 2-3 months to confirm you're reaching your target level. This evidence-based approach is far more effective than guessing.
Important reminders:
- If you take warfarin, consult your GP before starting K2 supplementation
- If you have any chronic medical condition, discuss supplementation with your GP first
- Take with a fat-containing meal for optimal absorption
- Consistency matters more than perfect timing — build it into a daily routine
Explore the Welzo Ultra Purity D3 + K2 Drops.
About the author
Dr Muhammad Zeeshan Afzal, MBBS | FCPS | MRCP is a practising medical doctor with extensive training and experience in cardiovascular medicine and clinical nutrition. He holds an FCPS degree from the College of Physicians and Surgeons of Pakistan and has successfully completed both Part 1 and Part 2 of the MRCP examinations from the Royal College of Physicians and Surgeons.
Dr Afzal is an independent product reviewer and content creator. He is not part of any product company's medical team. His evaluation methodology prioritises real-world clinical outcomes, label clarity, dosing transparency, and adherence to evidence-based standards.
This article is for general information and is not a substitute for personalised medical advice. Vitamin D3 + K2 supports normal physiological functions; these statements have not been evaluated by regulatory agencies and supplements are not intended to diagnose, treat, cure, or prevent any disease. People taking warfarin or other vitamin K-dependent anticoagulants must consult their GP before starting K2 supplementation. Pregnant or breastfeeding women, people with hypercalcaemia, hyperparathyroidism, or sarcoidosis, and those with chronic medical conditions should consult their GP before supplementing. Children's vitamin D requirements differ from adults' — follow NHS guidance and consult your GP or health visitor before starting paediatric supplementation. Dr Muhammad Zeeshan Afzal is a practising medical doctor writing in an editorial capacity as an independent product reviewer and content creator. He has no commercial affiliation with any of the brands reviewed in this guide.
References
- Schurgers LJ, Teunissen KJ, Hamulyák K, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007;109(8):3279-3283.
- Sato T, Schurgers LJ, Uenishi K. Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women. Nutr J. 2012;11:93.
- Holick MF. The vitamin D deficiency pandemic: Approaches for diagnosis, treatment and prevention. Rev Endocr Metab Disord. 2017;18(2):153-165.
- van Ballegooijen AJ, Pilz S, Tomaschitz A, et al. The Synergistic Interplay between Vitamins D and K for Bone and Cardiovascular Health. Int J Endocrinol. 2017;2017:7454376.
- Public Health England. SACN vitamin D and health report. 2016. (NHS guidance on vitamin D supplementation, autumn/winter recommendations)
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