Bio-Avail D3/K2

3-6 month supply

A Highly Absorbable Blend of Vitamins D3 and K2

Bio-Avail D3/K2

3-6 month supply

A Highly Absorbable Blend of Vitamins D3 and K2

Restore optimal D3 and K2 levels with this clean, easy-to-absorb, liquid formula.

  • Supercharge your immune, metabolic, cardiovascular, and bone health

  • Flexible dosing: 1,000 IU of D3 and 120 mcg of K2 per one-drop serving

  • Only 3 ingredients: MCT oil, D3, and K2. No artificial fillers or junk!

  • High-potency formula (600 servings per bottle!) saves you money and time.

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60-day Returns


Overcome Vitamin D Inadequacy (>90% of Americans)

Support immune function, heart and metabolic health, mood, cognitive function, strong bones


Protect Your Bones and Heart

Experience the synergistic benefits of D3 and K2 for cardiovascular and bone health.


Fine-Tune Your Daily Dose

With 1,000 IU of D3 and 120 mcg of K2 per drop, our flexible liquid formula makes it easy to get exactly the amount you need.


Affordable and Efficient D3/K2 Benefits

Our high-potency formula provides a clean source of D3/K2 at less than 6 cents per serving.

Powerful Nutrients & Vitamins

Vitamin D3

Vitamin D3

1,000 IU of vitamin D3 in a highly absorbable, liquid form. Avoid seasonal fluctuations of vitamin D levels and optimize your intake no matter where you live or what time of year it is. 

Vitamin K2

Vitamin K2

120 mcg of vitamin K2 in MK-4 form. Get the full benefits of vitamin K2 by taking one of the most effective forms.



MCT oil is a perfect carrier for D3 and K2 because it is rapidly absorbed and is a great energy source. It has a clean, neutral taste with no sweeteners, artificial flavors, binders, or fillers.

Signs You Need Bio-Avail D3/K2

Frequent colds & flu

Low mood

Weak bones

Metabolic difficulties

Brain fog, poor memory

Cardiovascular risk

What You'll Feel Using Bio-Avail D3/K2

  • Better immune function

  • Stronger bones

  • Sharper mind

  • Elevated mood

  • Healthier metabolism

  • Improved cardiovascular function

  • Greater longevity

60-Day Money Back Guarantee

60-Day Money Back Guarantee

We're confident you'll love our products, but if you're not completely satisfied, we offer a 60-day, 100% money-back guarantee on all purchases. Simply contact us for a full refund, no questions asked. Buy with confidence knowing you're covered by our guarantee.

The Adapt Naturals Standard

The Adapt Naturals Standard

In our increasingly toxic world, the last thing you want to worry about is a lot of artificial junk in your supplements. Adapt Naturals supplements are made with the cleanest possible ingredients, without gluten or GMOs. Our products are manufactured in a U.S. facility that meets the NSF’s rigorous GMP regulatory standards.

Third Party Lab-Tested

Third Party Lab-Tested

At Adapt Naturals, all of our products are third-party tested and validated, and we are always happy to share these results with customers. We want you to have full confidence that you’re getting exactly what you think you are with each purchase.

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Real Stories of Health and Happiness

  • "Great price for a high quality vitamin D that will last a VERY long time."

    —Lauren, Verified
  • “I really like the fact that these two vitamins are combined in liquid form.”

    —Dianne, Verified
  • “This is so easy to take daily!”

    —Michelle, Verified

Discover the Bio-Avail D3/K2 Advantage

Natural, whole-food
Synthetic, fillers
Maximally absorbable
Low absorption
Health Focus
Addresses root causes
Addresses symptoms
Clinical Background
15 years in-clinic
Not typically
Supports soil health
Disregards soil health
Single-use plastics
Functional Medicine expert

Meet Chris Kresser, your
Trusted Health & Wellness Guide

Founder & Functional Medicine Clinician

  • Globally renowned expert with over 15 years of experience
  • Dedicated to helping people improve their health by addressing modern challenges and nutrient gaps

Author & Educator

  • Treated thousands of patients
  • Trained more than 2,000 healthcare professionals
  • Gained valuable insights into functional medicine and nutrition

Why choose Bio-Avail D3/K2?

Our modern diets often fall short of providing the optimal amounts of essential nutrients our bodies need to function at their best. With the Bio-Avail D3/K2, you can overcome nutrient deficiency and support your overall health and well-being. We've done the research, so you don't have to!

Formulated to Replicate Optimal Ancestral Diets

Changes in dietary patterns, declining soil quality, and a growing toxic burden have made it increasingly difficult to obtain adequate nutrients from our daily food intake. Most Americans don’t get enough vitamin D and K2—with potentially serious consequences. With just a few drops of Bio-Avail D3/K2 daily, you’ll never have to worry about falling short of these critical nutrients again!

Harness Years of In-Clinic Experience and Ancestral Wisdom

Backed by Adapt Naturals' 15 years of in-clinic experience and dedicated to creating supplements that make a meaningful difference, Bio-Avail Omega+ combines cutting-edge research with insights from ancestral wisdom to bring you a premium-quality supplement.

Bio-Avail D3/K2

Unlock Your Optimal Health

Upgrade Your Wellness with Bio-Avail D3/K2—Lifelong Health, Simplified

Get Healthier & Happier - Try Now

Good For You—And the Planet

You can’t have healthy humans without a healthy planet. That’s why Adapt Naturals is working toward zero plastic and landfill waste in our supply chain.

Starting in the fall of 2023, we’re transitioning our packaging to 100% compostable, stand-up pouches. They’re made from cellulose (wood pulp) and are free of PLA, BPA, PFAS, phthalates, and other harmful chemicals. They’re printed with non-toxic, compostable ink. The pouches are so clean and biodegradable that you can put them in your backyard or curbside compost bin! 

Our sustainable packaging initiative will prevent over 120,000 plastic bottles from ending up in a landfill or the oceans. Thank you for being part of the solution and helping Adapt Naturals protect the beauty of our natural environment!

Your Questions Answered

Take one to five drops per day with or without food as directed by your healthcare provider. The optimal dosage will depend on your individual needs and whether you take vitamin D3 and/or K2 in other products.

We suggest consulting with your healthcare provider to determine your optimal dose of vitamins D3 and K2. Bio-Avail Multi contains 2,000 IU of vitamin D3 and 50 mcg of vitamin K2. Bio-Avail D3/K2 contains 1,000 IU of vitamin D3 and 120 mcg of K2 per serving/drop. This makes achieving your optimal dose of both nutrients easy according to your healthcare provider’s recommendations.

The shelf life is two years.

The MCT oil is derived from coconuts. This product is not suitable for people who are allergic to coconuts.

No, it is not vegan. The vitamin D3 is sourced from lanolin, which comes from the glands of wool-bearing animals.

Customer Reviews

Based on 26 reviews
Amber Barber

Love the ease of taking this product. I love that it is in glass. Feeling great!!

Hi Amber, We are glad to know you are loving our D3/K2. Thank you for leaving us a review and for supporting our brand!

Victor Cortes
Changed my!

A few months ago, I was diagnosed with hyperparathyroidism. My doctor suggested I start taking D3. I started taking Bio-Avail D3/K2, and within 6 weeks, my calcium levels decreased. My doctor was surprised and impressed. I still need to address the root cause of hyperparathyroidism, but Bio-Avail D3/K2 is helping me. Thank you!

Hi Victor, We are pleased to hear you are seeing improvements in your hyperparathyroidism since taking our D3/K2. We hope you will experience other benefits. Thank you for sharing your experience!

Maria Simpson
Bio-Avail D3/k2 - Great Combination

My husband and I have been taking Bio-Avail D3/K2 for several years. It is especially helpful during the winter months when we can't get enough sunshine and our Vit D levels get a bit low. Also, my dentist suggested I take a few extra drops than what is indicated on the bottle since I will be having a dental implant done. She said this would help the implant heal better since it is inserted into the bone. I also love how easy it is to take and that Adapt Naturals are clean products!

Hi Maria, Thank you for supporting Adapt Naturals. We are happy you found our D3/K2 supplement and its working well for you. We are truely greatful we could create an Adapt Natural line of supplements that supports the wellbeing of our customers. We appreciate your review!

Syndie Johnson
Loving it!

I have always known the benefits of taking a vitamin D supplement but now that it is in a liquid form with K2 make this so convenient. Highly recommend!

Hi Syndie, Thank you for reviewing our D3/K2. We hope you receive all the great benefits this product has to offer. Best of Health!

Jill J
It works!

I have definitely noticed a difference in how I feel!
The pain in my lower back is so much better and I an added bonus I am sleeping better.

Hi Jill,, We're glad you are noticing a reduction in back pain and improvements in your sleep since taking our D3/K2 supplement. Thank you for leaving us a review and for supporting our brand!