Vitamin D3 4000 IU & Vitamin K2 MK-7

Why D3 and K2 Belong Together

Vitamin D deficiency is staggeringly common, particularly in northern latitudes. Research consistently shows that a significant percentage of adults in the UK and northern US states have suboptimal vitamin D levels, especially during winter months. For anyone training hard, this matters because vitamin D plays a direct role in muscle function, recovery, testosterone production, and immune health.

Nutravita combines 4000 IU of vitamin D3 with 100mcg of vitamin K2 in the MK-7 form. The K2 inclusion is not just a marketing add-on — it serves a genuine purpose. Vitamin D increases calcium absorption, and vitamin K2 directs that calcium into bones rather than allowing it to deposit in arteries and soft tissues. They work synergistically.

Quality and Sourcing

Nutravita manufactures in the UK under GMP (Good Manufacturing Practice) conditions and submits each batch to third-party testing. The D3 is derived from lanolin (sheep wool oil), which is the standard for non-vegan D3 supplements. The K2 uses the MK-7 form, which has a longer half-life and better bioavailability than the cheaper MK-4 form used by some competitors.

Dosage and Practical Use

At 4000 IU per tablet, this is a sensible dose for most adults who are not already supplementing through fortified foods. It is above the RDA (which many researchers argue is set too low) but well within the safe upper limit. One tablet per day with a meal containing some fat is all that is needed — vitamin D is fat-soluble and absorbs better with dietary fat.

Who Needs This?

Anyone who trains indoors regularly, lives above the 37th parallel, or does not get consistent sun exposure should seriously consider D3 supplementation. It is one of the few vitamins where the evidence for supplementation in deficient populations is genuinely strong.

The Bottom Line

At roughly 6p per day for a 180-tablet bottle, this is one of the cheapest and most impactful supplements you can add to your stack. Nutravita delivers a well-dosed, properly formulated D3+K2 combination without premium pricing.