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Thorne Vitamin D + K2 Liquid

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Thorne Vitamin D + K2 Liquid

A liquid D3 + K2 with a four-line label at 6 to 11 cents a day. A June 2026 lab test found no metals or PFAS but two fluorinated fungicide residues, neither a PFAS by the OECD definition. NSF lists a capsule, not this liquid.

Best for People who want to set the D3 dose drop by drop and want K2 as MK-4, and do not take warfarin or other blood thinners.

Our rating
Fair (3.4 of 5)
Price range
Mid-range
Size
Liquid dropper bottle, about 1,200 drops (600 servings of 2 drops)

approx. $34 for the bottle (about 600 servings of 2 drops)

See it on Thorne’s site → (opens in a new tab)

We are not affiliated with Thorne. This link goes to the maker’s own page, with no tracking code. How we're funded.

Also sold at Vitacost ($34.00), Amazon ($28.90 with Subscribe & Save) .

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    Reviews are personal experiences, not research, and they never change our quality ratings. Every review is read by our team before it appears.

    How we evaluated it

    How it scores Our rating, metric by metric Fair, 3.4 of 5
    1. Ingredients 25% of the rating 4 of 5

      Two actives in MCT oil with mixed tocopherols as a preservative; no flavor, sweetener, color or flow agent.

    2. Independent testing 35% of the rating 3 of 5

      An independent June 2026 lab test of this exact product found no metals or PFAS and the lowest phthalates of 11, but two fluorinated fungicide residues (neither a PFAS by the OECD definition); the NSF listing is for the capsule, not the liquid.

    3. Evidence 15% of the rating 2 of 5

      D3 at 1,000 to 3,000 IU fits the guidelines, but 200 mcg of MK-4 is far below the doses our K2 page cites for that form and the page says the pair works better together than apart.

    4. Trust 10% of the rating 3 of 5

      Thorne settled a 2014 lead case for $250,000 and has two unresolved 2025 lead notices on other products; buyers report nausea on the liquid; it does not name a certifier.

    5. Value 15% of the rating 5 of 5

      $34 for 600 servings is $0.06 a day at 1,000 IU and $0.11 at 2,000 IU, with K2 included.

    The rating, 3.4 of 5, is the weighted average of these scores. See how we rank vitamins & minerals and our standard.

    Where to buy Stores and the prices we saw 2 stores
    • Vitacost (opens in a new tab) approx. $34.00. The 1 fl oz (30 ml) bottle, in stock on 2026-10-23. Its description says “Contents Certified NSF”; we could not find NSF’s own listing for the liquid.
    • Amazon (opens in a new tab) approx. $28.90 with Subscribe & Save. The 1 fl oz, 600-serving bottle, sold by Pattern, a third-party seller (we could not confirm whether Thorne authorizes it), and shipped by Amazon. The one-time price did not show to our tools, so the price here is the Subscribe & Save one (15 percent off) on 2026-10-23.

    Prices as we saw them on October 23, 2026. They change often. These links carry no tracking code and earn us nothing.

    What’s in it Every ingredient, in label order 4 ingredients
    1. Vitamin D3 25 mcg (1,000 IU)
    2. Vitamin K2 (menatetrenone, MK-4) 200 mcg
    3. Mixed tocopherols
    4. Medium chain triglycerides
    Who tested it What each test found, and who paid for it 1 test
    • Independent Mamavation (two EPA-certified labs; the site earns affiliate income and took donations from Environmental Health News and readers) June 2026

      “Thorne Vitamin D + K2 (drops)”: lead, arsenic, cadmium and mercury not detected; 40 PFAS chemicals not detected; glyphosate not detected; phthalates 170 ppb (127 ppb DEHP, 41 ppb DIBP), the lowest of 11 products; two pesticide residues, bixafen 0.010 mg/kg and fluxapyroxad 0.022 mg/kg. Mamavation’s raw data sits behind a free sign-up. Open ↗ (opens in a new tab)

    Who paid, and why it matters
    • Independent The tester took no money from the maker for it: a consumer group, a journalist, a university or a regulator.
    • Paid certification An outside lab or certifier tested or listed it, and the maker paid for that.
    • Maker’s own test A lab report or certificate of analysis the maker commissioned and published.

    A certification is a floor, not a verdict: it checks what its program checks and nothing else. We weigh tests by someone with no stake in the result most.

    What people ask Worries raised online and elsewhere, and what we found 7 questions
    What did the independent lab test find?
    Mamavation’s June 2026 vitamin D investigation (opens in a new tab) found no heavy metals, PFAS or glyphosate in Thorne’s liquid, and the lowest phthalates of the 11 products. It also found two pesticide residues (bixafen and fluxapyroxad), which put it in the “not our favorite” group. Every product tested had phthalates, and 7 of 11 had pesticides. We cannot see the raw data without an account, and the test covers a single sample of each product.
    Does fluxapyroxad count as a PFAS?
    Not by the usual definitions. Fluxapyroxad (C18H12F5N3O) is a fungicide whose fluorine sits in one difluoromethyl group (CHF2, which carries a hydrogen) and on a three-fluorine benzene ring (PubChem (opens in a new tab)); bixafen is built the same way (PubChem (opens in a new tab)). The OECD definition (opens in a new tab) counts a substance as a PFAS only if it has a fully fluorinated carbon, a CF3 or CF2 group with no hydrogen, chlorine, bromine or iodine on it. Neither compound has one, and Mamavation’s own test for 40 PFAS chemicals found none in this product. “Forever pesticide” is Mamavation’s label, and it does not say which definition it used. Fluxapyroxad is persistent in soil, with a typical half-life of 183 days in the Pesticide Properties DataBase (opens in a new tab), so we do not call it harmless, but our PFAS rule does not apply.
    How much fluxapyroxad is that?
    Very little. At 22 parts per billion, a 2-drop serving (about 0.05 mL of oil, going by 30 mL in about 1,200 drops) carries about one nanogram, by our arithmetic. The acceptable daily intake listed in the Pesticide Properties DataBase (opens in a new tab) is 0.02 mg per kg of body weight, about 1.4 million nanograms a day for a 70 kg adult. Mamavation tested one sample of one product, so this is a snapshot.
    Has anyone reported side effects from the liquid?
    Yes, a few anecdotes. One buyer on r/Supplements (opens in a new tab) (April 2026) reported dizziness and nausea after three days at 4 drops a day and wondered about the MCT oil; another post (opens in a new tab) (July 2026) reported headaches and nausea at up to three servings a day. We cannot confirm a cause. The label allows up to 6 drops a day.
    Is the K2 worth taking, and is MK-4 the right form?
    The evidence is thin. Our K2 page rests on one 3-year trial of 180 mcg of MK-7 and says artery protection is unproven. It describes MK-4 as short-lived and studied at 15 to 45 mg, against 200 mcg here, so we treat the K2 as a bonus, not a reason to buy.
    Does Thorne pay influencers and athletes to promote it?
    Yes. Thorne’s own ambassador page (opens in a new tab) says ambassadors earn a commission on every new customer who uses their link and receive free products. Its partners page (opens in a new tab) names athletes, a fitness coach and organizations such as the UFC, and states no terms. So a post saying “I use Thorne” may be paid.
    Has Thorne had lead or recall problems?
    Yes, in the past. Environmental Research Center v. Thorne Research settled in November 2014 for $250,000 over lead in dietary supplements, with warnings or reformulation and testing required (notice 2013-01044 (opens in a new tab)). A second 2014 notice named 13 Thorne products, none of them this one (2014-01211 (opens in a new tab)). In 2025 two new notices named Daily Greens Plus and Daily Electrolytes, with no settlement or judgment recorded (2025-02343 (opens in a new tab), 2025-03196 (opens in a new tab)). FDA records show two Class II recalls in 2014 of Captomer, a product sold as a supplement that FDA treated as an unapproved drug, closed in October 2014. We found no FDA warning letter.
    Why we chose it What put it on our list 4 points
    • The label is short and every amount is stated: vitamin D3 25 mcg (1,000 IU) and vitamin K2 as menatetrenone (MK-4) 200 mcg per serving of 2 drops, in medium-chain triglyceride oil preserved with mixed tocopherols. There are no flavors, sweeteners or colors.
    • It is cheap per day. At $34 for about 600 servings, 1,000 IU of D3 costs roughly $0.06 a day, and 2,000 IU (4 drops) about $0.11.
    • Mamavation sent this exact product to EPA-certified labs in June 2026. Lead, arsenic, cadmium and mercury were not detected, none of 40 PFAS chemicals was found, and its phthalates (170 ppb) were the lowest of the 11 vitamin D products tested. Mamavation still ranked it below its best picks because two pesticide residues were found.
    • Thorne’s page names the interaction plainly: vitamin K interferes with anticoagulant drugs such as Coumadin, and the two should not be used together.
    Trade-offs What to weigh before you buy 5 points
    • The June 2026 test found two pesticide residues: bixafen at 0.010 mg/kg and fluxapyroxad at 0.022 mg/kg, which are 10 and 22 parts per billion. Both are fluorinated fungicides. Mamavation calls fluxapyroxad a “PFAS forever pesticide”, but neither compound has the fully fluorinated carbon that the OECD definition of PFAS requires, and its own test for 40 PFAS chemicals found none. Our PFAS rule is not triggered, but pesticide residues in a supplement still cost points.
    • We have not confirmed independent certification for this product. Thorne’s page says it is “third-party tested and certified” without naming a certifier. NSF’s Certified for Sport database lists a “Thorne Vitamin D + K2” capsule (60 count, one lot), not the liquid.
    • K2 can interfere with warfarin (Coumadin) and similar blood thinners, and Thorne says to avoid using them together. Ask your prescriber first, or choose a vitamin D3-only product.
    • The label allows 2 drops up to three times a day. That is up to 3,000 IU of D3 and 600 mcg of K2 a day, close to the 4,000 IU upper limit for vitamin D.
    • The case for K2 is thin, and this is a different form from the one studied. Our K2 page describes one 3-year trial of 180 mcg of MK-7 a day and says protection of the arteries is unproven. It says MK-4 has a half-life of only about 1 to 2 hours and calls for multiple daily doses of 15 to 45 mg, against 200 mcg here.
    What to know Details worth knowing first

    Vitamin D3 is the form most people supplement, and our supplementation guide covers doses and testing. K2 is the add-on: our K2 page describes one trial in which MK-7 went with less bone loss in postmenopausal women, and says its effect on arteries is unproven. This product uses MK-4, a different form.

    The appeal here is the price per day, a very short label and a dropper that lets you set the dose. The doubts are the certifier listing we have not been able to confirm for the liquid, the warfarin interaction, and a June 2026 independent test that found no metals or PFAS but did find two pesticide residues.

    For what seals can and cannot tell you, see how to tell if a supplement is pure.

    What we checked Each claim, and how sure we are of it 7 checks
    Certificate of analysis
    No
    How Thorne Vitamin D + K2 Liquid measures up against our vitamins & minerals criteria
    What we checked What we found
    Third-party tested Maker’s claim Not confirmed as certified. Thorne’s page says the product has been “third-party tested and certified”, and its testing FAQ describes the NSF Contents Certified mark in general terms, but neither names a certifier for this liquid. NSF Certified for Sport lists a Thorne Vitamin D + K2 capsule, not this liquid. Mamavation, which is independent of Thorne, tested the liquid in June 2026. Vitacost’s description of the liquid says “Contents Certified NSF”, but we could not find NSF’s own listing.
    Independent lab test Verified Mamavation, June 2026: no lead, arsenic, cadmium, mercury, PFAS or glyphosate; phthalates 170 ppb; bixafen 0.010 mg/kg and fluxapyroxad 0.022 mg/kg.
    A certificate of analysis Not verified None on Thorne’s page. Thorne says it tests each ingredient for identity, purity and potency, including heavy metals, pesticides and microbes, and publishes no results.
    The right form Maker’s claim Vitamin D3 25 mcg (1,000 IU) and vitamin K2 as menatetrenone (MK-4) 200 mcg per 2 drops.
    A plain label Maker’s claim Two active ingredients with amounts, and two named other ingredients. No proprietary blend.
    Disclosed extras Maker’s claim Medium-chain triglycerides and mixed tocopherols. Thorne lists it as gluten-free, dairy-free and soy-free.
    K2 and blood thinners Maker’s claim Thorne’s warning: vitamin K interferes with anticoagulants such as Coumadin, so concurrent use should be avoided.
    What the labels mean
    • Verified We opened an independent record that confirms it: a certifier’s listing, a regulator’s list or a lab report. It is linked under Sources.
    • Maker’s claim The maker says so on its own page or label. We read it but found no independent record.
    • Not verified We looked and could not confirm it, or the maker does not say. Treat it as unknown.
    Sources Where our facts come from 19 sources
    1. Thorne Vitamin D + K2 Liquid product page. Maker’s page. Price, label amounts, directions, testing statements and warning as seen 2026-10-23. Open ↗ (opens in a new tab)
    2. Mamavation: Vitamin D supplements tested for pesticides, lead, PFAS and phthalates (8 June 2026). Test report. Eleven products sent to EPA-certified labs; Thorne Vitamin D + K2 (drops) is one. Mamavation earns affiliate income and took donations from Environmental Health News and readers; raw data needs a free account. Open ↗ (opens in a new tab)
    3. NSF Certified for Sport listing: Thorne Vitamin D + K2 (capsule, 60 count). Certifier or regulator listing. A capsule with one lot (417489). Not the liquid on this page. Open ↗ (opens in a new tab)
    4. Vitacost: Thorne Vitamin D + K2, 1 fl oz (30 ml). Independent source. A store listing (UPC 693749500018) that copies the label: medium chain triglyceride oil and mixed tocopherols. $34.00 and in stock on 2026-10-23. Its description says “Contents Certified NSF”. Open ↗ (opens in a new tab)
    5. Amazon: Thorne Vitamin D + K2 Liquid with a metered dispenser, 600 servings. Independent source. A store listing: ships from Amazon, sold by Pattern. The Subscribe & Save price was $28.90 (15 percent off) on 2026-10-23. Open ↗ (opens in a new tab)
    6. A New OECD Definition for Per- and Polyfluoroalkyl Substances (Environmental Science & Technology, 2021). Independent source. Written by staff of the OECD, ECHA, US EPA and others. The PubMed record has no abstract; the definition it sets out (a fully fluorinated CF3 or CF2 carbon with no H, Cl, Br or I attached) is quoted in the Vermont testimony below. Open ↗ (opens in a new tab)
    7. Testimony of Kyla Bennett (PEER) on Vermont bill S.197, 9 February 2024. Independent source. Quotes the OECD definition word for word and says most US states use a “one fully fluorinated carbon” test. PEER is an advocacy group that wants fluorinated pesticides treated as PFAS. Open ↗ (opens in a new tab)
    8. PubChem: fluxapyroxad. Independent source. Structure and formula C18H12F5N3O: a CHF2 group and three fluorines on a benzene ring, no CF3 or CF2 group. Open ↗ (opens in a new tab)
    9. PubChem: bixafen. Independent source. Structure and formula C18H12Cl2F3N3O: a CHF2 group and one fluorine on a benzene ring, no CF3 or CF2 group. Open ↗ (opens in a new tab)
    10. Pesticide Properties DataBase (University of Hertfordshire): fluxapyroxad. Independent source. A fungicide. Acceptable daily intake 0.02 mg per kg of body weight; typical soil half-life 183 days, labelled persistent. Open ↗ (opens in a new tab)
    11. Thorne Ambassadors. Maker’s page. Says ambassadors earn commission on referrals and receive free products. Open ↗ (opens in a new tab)
    12. Thorne Partners. Maker’s page. Lists athletes, a fitness coach and organizations including the UFC; no terms stated. Open ↗ (opens in a new tab)
    13. California Attorney General Prop 65 notice 2013-01044 (Thorne Research). Certifier or regulator listing. Lead in dietary supplements. Complaint filed 2014-03-17; settlement 2014-11-20, $250,000 in total payments; judgment 2015-01-28. Open ↗ (opens in a new tab)
    14. California Attorney General Prop 65 notice 2014-01211 (Thorne Research). Certifier or regulator listing. Lead or cadmium in 13 named Thorne products, none of them this one. No complaint or settlement is recorded. Open ↗ (opens in a new tab)
    15. California Attorney General Prop 65 notice 2025-02343 (Thorne Research). Certifier or regulator listing. Lead in Thorne Daily Greens Plus. No complaint, settlement or judgment recorded as of 2026-10-23. Open ↗ (opens in a new tab)
    16. California Attorney General Prop 65 notice 2025-03196 (Thorne Research). Certifier or regulator listing. Lead in Thorne Daily Electrolytes Drink Mix, Watermelon. No complaint, settlement or judgment recorded as of 2026-10-23. Open ↗ (opens in a new tab)
    17. openFDA drug enforcement records for Thorne. Certifier or regulator listing. Two Class II recalls begun 2014-06-12 of Captomer, sold as a supplement but made from DMSA, the active ingredient of an approved drug, so FDA treated it as an unapproved drug; both terminated 2014-10-15. Open ↗ (opens in a new tab)
    18. Reddit r/Supplements: Thorne Vitamin D3 K2 side effects (April 2026). Independent source. One buyer’s report of dizziness and nausea. Anecdote. Open ↗ (opens in a new tab)
    19. Reddit r/Supplements: Thorne Vitamin D + K2 liquid experiences? (July 2026). Independent source. One buyer’s report of headaches and nausea. Anecdote. Open ↗ (opens in a new tab)
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