Ingredient evidence
Vitamin D and K2
The one supplement UK public health actively recommends, plus a partner nutrient with a plausible rationale and thinner evidence than its marketing suggests.
Also sold as: vitamin D3, cholecalciferol, MK-7, menaquinone.
Our read of the evidence
Good evidence
Multiple decent human trials point the same way.
Vitamin D is a genuine UK public health recommendation. K2 is reasonable, optional and oversold.
Why vitamin D is different from every other supplement
The UK sits too far north for skin to make vitamin D from sunlight between roughly October and March. This is not a wellness claim, it is geography, and it is why UK health advice recommends everyone consider a daily 10 microgram supplement over winter, and year-round for people who cover up, have darker skin, or spend little time outdoors.
Deficiency matters. Severe deficiency causes bone pain and muscle weakness, and low status is common in exactly the groups this site serves. What vitamin D does not do is the long list of things it has been trialled for and failed: large trials have not shown that supplementing prevents cancer, cardiovascular disease or depression in people who are not deficient.
In pregnancy, vitamin D is specifically recommended throughout, and it is included in the UK Healthy Start vitamin scheme.
Does K2 actually add anything?
Vitamin K2 activates proteins that help deposit calcium in bone and discourage it from settling in arteries. That mechanism is real, and it is why combination products exist. What is missing is convincing evidence that adding K2 to a normal vitamin D dose changes fracture or cardiovascular outcomes in people eating an ordinary diet.
The practical position: if a D3+K2 product costs much the same as D3 alone, there is little reason not to take it. If it costs three times more, you are paying for a mechanism rather than a proven outcome. Anyone on warfarin must not take K2 without medical advice, because vitamin K directly opposes how warfarin works.
How to take it.
- Typical dose
- 10 micrograms (400 IU) vitamin D daily; K2 as MK-7 typically 75-100 micrograms
- Form
- D3 (cholecalciferol) is better than D2; vegan D3 from lichen is available
- Timing
- Daily, with a meal containing some fat
- Worth knowing
- The UK safe upper level for adults is 100 micrograms (4,000 IU) a day. Higher doses should only be taken on the basis of a blood test and clinical advice.
What it will not do.
- It will not improve mood or energy if your levels are already adequate
- It will not prevent cancer or heart disease
- It will not build bone on its own without weight-bearing exercise and enough calcium and protein
Who should avoid it.
- You take warfarin - do not take K2 without your anticoagulation clinic's agreement
- You have high blood calcium, sarcoidosis or kidney stones, unless supervised
- You are already taking prescribed high-dose vitamin D
Raise with a prescriber
- Vitamin K2 opposes warfarin and can destabilise INR control
- Some diuretics and steroids affect calcium handling - flag it if you take them
- Do not stack multiple products each containing vitamin D without adding up the total
Products containing vitamin d and k2.
Everything below is stocked in the UK. Compare on the active dose and the cost per day rather than the size of the pack.
| Product | Key actives | Form | Price | Per day | Best for |
|---|---|---|---|---|---|
| Daily Multi Nutrient for WomenWild Nutrition | Iron, Vitamin D3, Vitamin K2, B-complex | Capsule | £30/month | £2.00 | Daily foundational nutrition, Women in their reproductive years, Anyone starting from scratch |
| Peri-BoostMPowder | Sage, Maca, B-complex, Magnesium, Vitamin D3 | Powder | £55/month | £1.83 | Perimenopause, Hot flushes, Perimenopausal fatigue |
| Wild Nutrition Food-Grown Vitamin DWild Nutrition | Vitamin D | Capsule | £21.00 | 70p | UK winter, Low sun exposure |
| Wild Nutrition Menopause ComplexWild Nutrition | Magnesium, Vitamin D, B vitamins, Botanicals | Capsule | £42.00 | £1.40 | Broken sleep, Night-time cramps, UK winter |
| Wild Nutrition Women's Daily Multi NutrientWild Nutrition | Multivitamin, Iron, Vitamin D | Capsule | £44.00 | £1.47 | UK winter, Low sun exposure, Confirmed low ferritin |
| DR.VEGAN Vitamin D3 & K2DR.VEGAN | Vitamin D3, Vitamin K2 MK-7 | Capsule | £12.99 | 22p | UK winter, Low sun exposure |
| Bare Biology Beam & Balance Vitamin D3 with K2 SprayBare Biology | Vitamin D3, Vitamin K2 | Spray | £21.95 | - | UK winter, Low sun exposure |
| ARTAH Essential D3/K2ARTAH | Vitamin D3, Vitamin K2 MK-7 | Capsule | £26.00 | 43p | UK winter, Low sun exposure |
| Together Health Vitamin D3 and K2Together Health | Vitamin D3, Vitamin K2 | Capsule | £15.95 | 53p | UK winter, Low sun exposure |
| Viridian Vitamin D3 & K2Viridian Nutrition | Vitamin D3, Vitamin K2 | Capsule | £31.85 | 35p | UK winter, Low sun exposure |
Prices are the brand's UK list price at the time of writing and change often. Cost per day is calculated from pack size and the label's daily serving, and is shown only where both are published.
Common questions.
How much vitamin D should I take in the UK?
10 micrograms (400 IU) daily, at minimum from October through March, and year-round if you have darker skin, cover up, or are rarely outdoors.
Do I need K2 with vitamin D?
It is optional. The mechanism is plausible and the risk is low, but there is no strong outcome evidence that it is necessary. Never take it if you are on warfarin.
Can you take too much vitamin D?
Yes. Sustained high doses raise blood calcium and can damage the kidneys. Stay at or under 100 micrograms (4,000 IU) daily unless a clinician has tested you and advised otherwise.
Is vitamin D important in perimenopause?
It matters for bone health, which becomes more important as oestrogen falls. It is a supporting player alongside resistance training, protein and calcium, not a treatment for menopausal symptoms.
Where this comes from.
A supplement is not clinical care.
If symptoms are affecting your work, your sleep or your relationships, the useful next step is an assessment rather than another purchase. Our check-in takes three minutes and points you to the right kind of clinician.
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Food supplements are not medicines and are not intended to diagnose, treat or cure any condition. They should not replace a varied diet or prescribed treatment. If you are pregnant, breastfeeding, taking medication or managing a diagnosed condition, check with a pharmacist or clinician before starting anything on this page. We do not accept payment for inclusion or placement. Where a link earns us a commission we say so on the product page. Last reviewed 27 August 2026.