Thorne Vitamin D + K2
A liquid D3 + K2 combination that skips the softgel: 1,000 IU D3 and 200mcg K2 (MK-4) per two-drop serving, in an MCT-oil base, third-party tested.
Vitamin D and K2 are often taken together for a simple reason, and Thorne packs both into a liquid that sidesteps the main annoyance of D supplements: swallowing yet another softgel.
Vitamin D increases how much calcium your body absorbs, and vitamin K2 helps direct that calcium toward bone rather than soft tissue, which is why the two are so often paired. Thorne combines them in a liquid: two drops deliver 1,000 IU (25mcg) of vitamin D3 and 200mcg of vitamin K2 as MK-4, in a base of MCT oil so the fat-soluble vitamins absorb properly. A single 1 fl oz bottle holds around 600 servings, so it lasts a long time and the per-day cost is trivial.
Thorne states the product is third-party tested for label accuracy and purity. Note that, unlike Thorne's creatine and magnesium, this liquid is not in the NSF Certified for Sport registry, so a drug-tested athlete who needs that specific certification should choose a certified vitamin D SKU instead.
At $34 it is an inexpensive, low-friction way to cover the vitamin D and K2 most people under-consume, especially in low-sun months, though your dose should be guided by your actual vitamin D bloodwork rather than a default.
Anyone who wants an easy, liquid way to cover vitamin D and K2, especially in low-sun months, and who dislikes swallowing softgels.
You need an NSF Certified for Sport vitamin D (this SKU is not certified), or your bloodwork already shows a high vitamin D level.
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Thorne Vitamin D + K2 Liquid cross-shops across several editorial surfaces - the full brand catalog, the buyer-intent tags this item carries, the price band it qualifies for, and any execution playbook that uses it, plus the in-depth guides that cover it.
Thorne Vitamin D + K2 Liquid - buyer FAQ
How much vitamin D and K2 per serving?
Two drops deliver 1,000 IU (25mcg) of vitamin D3 and 200mcg of vitamin K2 as MK-4. Note the dose is per two-drop serving, not per drop. 1,000 IU is a sensible maintenance dose for many adults, but the right amount depends on your blood level, so test before assuming you need more.
Why take vitamin D with K2?
Vitamin D increases how much calcium your body absorbs, and vitamin K2 helps direct that calcium into bone rather than soft tissue. The two are commonly paired for this reason. Thorne uses the MK-4 form of K2 in an MCT-oil base so both fat-soluble vitamins absorb well.
Is this Thorne D + K2 liquid NSF Certified for Sport?
No. This specific liquid is not listed in the NSF Certified for Sport registry. Thorne states it is third-party tested for label accuracy and purity, which is a quality check but not the same as the independent NSF-for-Sport banned-substance certification. If you are a drug-tested athlete who needs the NSF-for-Sport seal on your vitamin D, choose a Thorne SKU that explicitly carries it.
Is liquid better than capsules for vitamin D?
Not inherently, but it is more convenient for some people: no softgel to swallow, easy to adjust the dose, and the MCT-oil base supports absorption of the fat-soluble vitamins. The main practical advantage is compliance, since a long-lasting liquid is easy to keep taking. Let your bloodwork, not the format, set your dose. Nothing here is medical advice.