Pre-order: one or more items in this bundle are on pre-order. We'll dispatch your bundle as soon as all items are in stock (due in stock early November 2026).
Two winter staples, Vitamin D3 + K2 and Dual Vitamin C, together for less.
What's in the bundle
- Vitamin D3 4,000 IU + K2: vitamin D3 100µg (4,000 IU) with vitamin K2 (MK-7) 100µg per capsule. Vegetarian capsule.
- Dual Vitamin C: 500mg vitamin C (625% NRV) per capsule, as 250mg ascorbic acid and 250mg calcium ascorbate, plus 25mg citrus bioflavonoids and 10mg zinc (100% NRV) as bisglycinate. 1 or 2 capsules daily. Vegan capsule.
Key benefits
- Vitamin D contributes to the maintenance of normal bones, teeth and muscle function.
- Vitamin D contributes to the normal function of the immune system.
- Vitamin K contributes to the maintenance of normal bones and to normal blood clotting.
- Vitamin C contributes to the normal function of the immune system and the reduction of tiredness and fatigue.
- Vitamin C contributes to normal collagen formation for the normal function of skin.
- Vitamin C contributes to the protection of cells from oxidative stress and increases iron absorption.
- Zinc contributes to the normal function of the immune system.
Why Dr Marks?
Formulated by practising UK GPs, using active forms absorbed more effectively (bioavailable) where it matters, safely dosed for everyday use (formulated within UK EVM and European guidance levels) when used as directed, and bundled so you can save compared with buying each product separately.
Directions
- Vitamin D3 4,000 IU + K2: One capsule daily with food.
- Dual Vitamin C: 1 or 2 capsules daily with food and water (no more than 2 capsules a day).
Do not exceed the recommended dose of any product. Dual Vitamin C is suitable for vegans and vegetarians (MCT powder on acacia gum carrier); Vitamin D3 + K2 is suitable for vegetarians (not suitable for vegans, as D3 is sourced from sheep's wool lanolin). Made in a factory that also handles milk, egg, fish and crustaceans.
Cautions & interactions
- Do not take alongside other vitamin D supplements or multivitamins containing vitamin D. 100µg (4,000 IU) is the maximum daily amount of vitamin D for adults.
- If you are pregnant, breastfeeding, taking any prescribed medication (including blood-thinning medication) or under medical supervision, please consult your doctor or pharmacist before use. Leave 2–4 hours between taking mineral supplements and regular medication.
- Dual Vitamin C contains 10mg zinc per capsule (20mg in 2 capsules); keep total zinc from supplements at or below 25mg a day.
- Contains citrus (bioflavonoids).
Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Keep out of reach of children.
A GP’s View on Supplement Timelines
Consistent Daily Use: What Happens in the Body
Many supplement brands print fixed charts promising rapid changes in a set number of days. As practising UK GPs, we prefer an honest approach: food supplements are designed for supporting your daily nutritional intake alongside a balanced diet, where nutrients work quietly and consistently in the background as part of your everyday routine.
Days 1–7
Daily routine & digestive comfort
Take 1 capsule a day with a main meal and water. Taking your capsule with food is gentler on the stomach and helps fat-soluble vitamins absorb normally.
Weeks 2–6
Steady daily nutritional intake
Consistent daily intake helps top up your diet every day rather than in sporadic bursts. Water-soluble nutrients (such as B vitamins and vitamin C) are used daily and aren’t stored in large amounts, while fat-soluble nutrients (such as vitamin D) build up gradually with steady daily intake.
Weeks 8–12 (1–2 pouches)
Long-term maintenance & routine review
Nutritional supplements work gradually alongside your normal diet — we recommend reviewing your routine after 3 months of consistent daily use. For everyday dietary top-ups, steady ongoing habits matter most.
Not sure which one you need? Take the free 60-Second GP Nutrient Check
60 seconds, results straight away. No email needed.
Dr Marc CrutchleyMBChB MRCGP MSc BSc (Hons), Co-founder
Dr Mark WilshereMBChB MRCGP DCH BSc (Hons), Co-founder
GP-Formulated in the UK✓ GMC-Registered Practising UK GPs · 40+ Years Combined Experience
Meet the GPs behind Dr Marks
Formulated by Dr Marc Crutchley and Dr Mark Wilshere, practising UK GPs.
With over 40 years of combined clinical experience as GMC-registered UK GPs, we formulate every Dr Marks supplement using nutrient forms absorbed more effectively (bioavailable) at meaningful daily doses — in clean plant-based capsules (HPMC) with zero synthetic tablet binders or glazes.
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