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4.98 from 43 reviews

Time to get serious about your D.

Clean, liquid D3 + K2 in organic olive oil. Three ingredients. Nothing else.

70% of Americans are low on vitamin D.1 See why it matters ↓

Shop D3X20% off + free shipping

$22.40/bottle on the 3-month plan · 75¢ a day

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D3X Vitamin D3 + K2 dropper bottle on dark slate with olive branches and a bowl of olive oil
Organic olive oilMade in USA

People who take it daily

Read all 43 reviews →
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“The first thing I noticed was how premium the bottle feels. It definitely doesn’t come across like a cheap supplement, and I really like that it comes in glass instead of plastic. The drops are super easy to use. I usually just add them to my smoothie. Would definitely recommend!”

Nick M.Verified buyer

“Thank you for the clear and concise packaging explaining the benefits of incorporating this into my daily routine. The easy-to-use dropper paired with the smooth liquid makes it worthwhile. Glad to be a returning customer!”

Samuel G.Verified buyer

“I ordered D3X a few weeks ago. My favorite thing about it is how when I mix it in my shake you cannot tell it’s there. Super easy!”

Lulu F.Verified buyer

Vitamin D isn't a trend. It's a necessity.

It's one of the most researched nutrients on earth, your body has receptors for it almost everywhere, and most Americans don't get enough. No one can patent it, so no one spends millions telling you to take it.

65,000+research papers on vitamin D, and counting12
1,000+genes vitamin D helps regulate13
Head to toeVitamin D receptors are found in nearly every tissue in your body3
70%of Americans are low on vitamin D1

All of that, for 75¢ a day.$22.40/bottle on the 3-month plan · free shipping · cancel anytime

Start the habit

A gap hiding in plain sight

Low vitamin D status is the most widespread nutritional gap worldwide,3 yet it slips past most people. It rarely gets tested, rarely gets talked about, and almost never gets fixed properly.

01
Why it happensIndoor lifestyles, poor diets, seasons, geography, sunscreen, and inconsistent sun exposure.
02
Why it's missedIt isn't routinely tested for, so many people don't connect how they feel to being low.
03
Why it mattersVitamin D acts more like a hormone than a vitamin, influencing gene-related processes throughout the body.3*

Built for one thing. Done right.

Plenty of brands sell vitamin D. Almost none are built for it. We make one product, so every decision goes into the bottle.

Feature
D3X
Regular vitamin D
Vitamin D
D3 (cholecalciferol)
Some use D2
K2
100 mcg MK-7 included
Usually none
Form
Liquid in organic olive oil
Pills or softgels, often in soybean oil
Ingredients
3: D3, K2 + olive oil
Often gelatin, glycerin or fillers
Bottle
Glass, 1 mL dropper
Often plastic
Quality
USA-made, cGMP, third-party tested
Varies by brand
Shop D3X See lab results →
Only three ingredients
01
Vitamin D3
2000 IU · Cholecalciferol

The form your body makes from sunlight. Raises and maintains vitamin D levels more effectively than D2.8*

02
Vitamin K2
100 mcg · MK-7

D3 helps you absorb calcium; K2 helps direct where it goes.9* MK-7 stays active longer than other forms.10

03
Organic olive oil
Organic · No seed oils

Vitamin D is fat-soluble, so it absorbs best with fat. Olive oil, not the seed oils most supplements rely on.

No dyes, sweeteners, fillers or proprietary blends.

D3X liquid Vitamin D3 + K2 bottle on a kitchen counter next to a mug of coffee and a bowl of olives

A habit that actually sticks

  1. 01
    1 mL, once a dayInto your coffee, shake, food, or straight under your tongue. Three seconds, works the same either way.
  2. 02
    Same time, every dayAnchor it to something you already do: morning coffee, pre-workout, breakfast.
  3. 03
    Keep it goingConsistency is where it works. Every box has a fold-out guide, you get reminders, and the subscription ships on its own. Skip or cancel anytime.
Start my subscription When and how to take it →

Worth asking

Straight answers on shipping, cancelling and dosing.

D3X bottle on a sunlit windowsill with an olive leaf
Can I cancel anytime?
Yes, anytime, in two clicks from your account. Pause, skip, or cancel. No fees, no calls.
When does it ship?
All orders ship free in the US. Orders placed by noon Eastern on a business day ship the same day; later orders ship the next business day. You'll get tracking by email.
How do I take it?
One full dropper (1 mL) daily. Take directly by mouth, or add to coffee, a protein shake, smoothie, yogurt, or food. Same time each day. Reassess at 8 to 12 weeks.*
Why D3 and K2 together?
D3 helps your body absorb calcium; K2 helps direct where that calcium goes, supporting proper distribution and balance.9* We use K2 as MK-7 because it stays active longer than other forms,10 making it a better fit for consistent daily use.
Is 2,000 IU the right amount?
2,000 IU is a common daily amount for adults and sits well under the 4,000 IU daily upper limit for adults set by the National Academies. If you already take vitamin D, are pregnant or nursing, or take medication, check with your doctor first.
How is D3X different from other vitamin D supplements?
Three things. What's in the bottle: an olive oil base, a glass bottle, three ingredients, with no seed oils, fillers, sweeteners, or proprietary blends. What we make: one product. Vitamin D is the entire company, not a line item among hundreds. What happens after you buy: a fold-out guide in every box, reminders, and a subscription timed to your routine.
Can you get enough vitamin D from sunlight alone?
Sunlight is a natural source of vitamin D3, produced by the skin in response to UVB exposure.* However, time of day, season, skin tone, location, clothing, sunscreen, and time spent indoors can limit how much your body produces.11* Many people use a supplement like D3X to support their levels consistently through the year.*
What are common signs of low vitamin D?
Low vitamin D levels may be associated with general fatigue, reduced motivation, or changes in mood or focus in some individuals.* These experiences are nonspecific and can result from many factors. Talk to a healthcare provider to understand your individual needs.
How is D3X different from a multivitamin?
Multivitamins spread small amounts across dozens of ingredients. D3X focuses on the one thing most people are actually missing, in a liquid format built for daily consistency, not pill fatigue.
D3X liquid vitamin D3 + K2
4.98 from 43 reviews

Time to get serious about your D.

3-MonthBest value3 bottles at once · $67.20 every 90 days
$30.20$22.40/bottle
Monthly1 bottle/month · cancel anytime
$35.00$27.20/bottle
One-timeSingle bottle, no commitment
$39.00$31.20/bottle
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Sources & research

Every health claim on this page is backed by peer-reviewed research.

All research →
ResearchBest Vitamin D for Seniors: What Changes After 60, and What to Take
ResearchVitamin D 2,000 IU vs 5,000 IU: Which Should You Take?
ResearchBest Vitamin D Supplement for Women: What to Look For at 30, 40, 50 and Beyond
View all sources13
  1. 1
    Vitamin D deficiency and insufficiency among US adults: prevalence, predictors and clinical implicationsBritish Journal of Nutrition · 2018View study
  2. 2
    What do we know about spending related to public health in the U.S. and comparable countries?Peterson-KFF Health System Tracker · 2020View source
  3. 3
    Vitamin D DeficiencyHolick MF · New England Journal of Medicine · 2007View study
  4. 4
    Vitamin D Supplementation and Sleep: A Systematic Review and Meta-Analysis of Intervention StudiesAbboud · Nutrients · 2022View study
  5. 5
    The effect of vitamin D supplementation on depression: a systematic review and dose-response meta-analysis of randomized controlled trialsMikulska et al. · 2024 · 31 trials, 24,189 participantsView study
  6. 6
    Effect of vitamin D supplementation on upper and lower limb muscle strength and muscle power in athletes: A meta-analysisZhang et al. · PLOS ONE · 2019View study
  7. 7
    A Systematic Review and Meta-Analysis of The Effect of Low Vitamin D on CognitionGoodwill & Szoeke · Journal of the American Geriatrics Society · 2017View study
  8. 8
    Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysisTripkovic et al. · American Journal of Clinical Nutrition · 2012View study
  9. 9
    Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam StudyGeleijnse et al. · Journal of Nutrition · 2004View study
  10. 10
    MK-7 and Its Effects on Bone Quality and StrengthSato et al. · Nutrients · 2020View study
  11. 11
    Sunlight and Vitamin D: A global perspective for healthWacker & Holick · Dermato-Endocrinology · 2013View study
  12. 12
    Mapping the landscape of vitamin D in cancer studies: a systematic global investigationBibliometric review · 2025 · counts over 65,000 PubMed publications on vitamin D by June 2022View study
  13. 13
    Vitamin D: A Micronutrient Regulating GenesCarlberg C · Current Pharmaceutical Design · 2019View study