• Vitamins and Supplements
• Menopause
• Osteoporosis

The Benefits of Taking Vitamins D3, K2, and Calcium Together

Medically reviewed and edited by Kerri Louati, MS, RD, LD, CDE

Published: August 14, 2025
Updated: November 04, 2025
4 mins

As we age, maintaining strong bones and overall wellness becomes increasingly important. This is especially true for women navigating menopause, when hormonal changes can accelerate bone loss and increase the risk of osteoporosis. Vitamins play a critical role in supporting these needs, with certain nutrients working best in combination. 

As we age, maintaining strong bones and overall wellness becomes increasingly important. This is especially true for women navigating menopause, when hormonal changes can accelerate bone loss and increase the risk of osteoporosis. Vitamins and minerals play a critical role in supporting these needs, with certain nutrients working best in combination. 

One of the best-studied nutrient combos for bone health is vitamin D3, K2, and calcium. Together, they help your body absorb calcium better, get it into your bones, and keep it from building up in places it shouldn’t, like your arteries.

What is Vitamin D3?

Vitamin D3 – or cholecalciferol – is the form of vitamin D produced in the skin after exposure to ultraviolet B (UVB) sunlight and the form most commonly used in supplements. Once vitamin D is made in the body or absorbed from food, the liver and kidneys convert it into its active form, calcitriol. In this form, it acts like a hormone, helping regulate calcium levels, support bone health, and influence immune function and other important cellular processes. 

Although vitamin D3 is best known for its role in supporting calcium absorption and bone strength, its influence extends far beyond skeletal health. It plays a crucial part in immune regulation, inflammation control, muscle function, and mood balance. Research links low vitamin D levels to fatigue, mood changes, and increased risk for infections. 

Because estrogen enhances vitamin D receptor activity and supports calcium utilization, declining estrogen levels during menopause may reduce the body’s ability to use vitamin D efficiently. Ensuring adequate vitamin D3 intake, through sunlight, diet, or supplementation, helps counter these changes, supporting bone integrity, immune resilience, and overall health.

What is Vitamin K2?

Vitamin K2 is a fat-soluble vitamin that plays a key role in bone formation and cardiovascular health. It helps activate proteins such as osteocalcin and matrix GLA protein, which guide calcium into the bone matrix and prevent it from accumulating in blood vessel walls. In doing so, K2 supports healthy bone mineralization while maintaining flexible, clear arteries.

While often overshadowed by vitamin D, K2 is equally important for long-term skeletal strength and heart health. Adequate intake helps reduce the risk of bone loss and arterial calcification (hardening of the arteries) as we age, making K2 an essential component of comprehensive bone and cardiovascular support.

What is Calcium?

Calcium is the most abundant mineral in the body and forms the foundation of strong bones and teeth. It also supports critical functions such as muscle contraction, nerve signaling, and maintaining a steady heartbeat. When calcium intake or absorption is insufficient, the body draws calcium from bone stores to keep blood levels stable, which can gradually reduce bone strength over time.

For women during and after menopause, maintaining healthy calcium levels is essential to help offset age-related changes in bone density and support long-term skeletal health. Adequate intake from both food and high-quality supplements can help preserve bone structure, promote muscle and nerve function, and contribute to overall wellness as the body’s natural hormone balance shifts with age.

Why Should You Take D3, K2, and Calcium Together?

Taking vitamin D3, K2, and calcium together creates a powerful synergy that supports bone, cardiovascular, and overall metabolic health. Vitamin D3 enhances calcium absorption from food and supplements, while calcium provides the essential mineral that strengthens bones and teeth. Vitamin K2 works in tandem with D3 by guiding calcium into bone tissue, where it belongs, and preventing it from accumulating in arteries or soft tissues. This coordination ensures that calcium is efficiently absorbed, properly utilized, and safely regulated throughout the body.

For women navigating menopause and beyond, when declining estrogen levels accelerate bone loss, this combination can be especially beneficial. It supports bone density, helps maintain skeletal integrity, and reduces the risk of fractures. By optimizing calcium metabolism, D3 and K2 also support muscle function, cardiovascular health, and metabolic balance as you age.

Forms and Dosage Options

Vitamin D3, K2, and calcium work best when taken in bioavailable, properly balanced forms that the body can easily absorb and utilize.

Vitamin D3, or cholecalciferol, is the preferred form of vitamin D. It is commonly available as capsules, softgels, or liquid drops. Most adults benefit from 1,000 to 4,000 IU daily for maintenance, although higher doses may be used short-term under practitioner supervision to correct deficiencies. Because it is fat-soluble, D3 should be taken with a meal containing healthy fats to optimize absorption.

Vitamin K2 is available in two well-studied forms: MK-4 and MK-7. Both support the activation of proteins that help direct calcium into bones and reduce its accumulation in arteries. While MK-7 tends to sustain measurable blood levels at lower nutritional doses, MK-4 has been used clinically at higher doses for bone support as well. A common supplemental range for K2 is 100–200 mcg daily, taken alongside vitamin D3 with a meal that includes healthy fats to enhance absorption and synergy.

Calcium is easiest for the body to use when it comes from whole-food sources, like algae-based calcium or microcrystalline hydroxyapatite concentrate (MCHC), which naturally include other minerals that support bone health. If whole-food sources aren’t available, synthetic options like calcium malate or calcium citrate can be used. When taking these supplements, it’s important to get enough vitamin K2 to help your body use calcium effectively. Most adults do best with a total of 700 to 1,200 mg of calcium per day from food and supplements, split into smaller doses for better absorption.

Combination D3, K2, and calcium formulas are available in capsules, softgels, powders, or liquids. Liquid emulsions are especially helpful for those with absorption challenges. Because optimal dosing depends on factors like age, hormone status, diet, and sun exposure, it is best to work with a qualified practitioner and monitor nutrient levels through lab testing for vitamin D and calcium status.

Dietary Sources of D3, K2, and Calcium

While supplementation is often necessary to achieve optimal levels, incorporating foods rich in vitamin D3, K2, and calcium provides a strong nutritional foundation.

Vitamin D3 is found in small amounts in fatty fish such as salmon, sardines, and mackerel, as well as in egg yolks and fortified foods. While these foods contribute to maintaining baseline vitamin D levels, the most effective and natural source of vitamin D is sunlight exposure, which stimulates vitamin D production in the skin. Because dietary sources alone rarely provide enough to achieve optimal levels, most people benefit from regular sun exposure and, when needed, supplementation to reach and maintain healthy vitamin D status.

Vitamin K2 is naturally produced by certain bacteria during fermentation. The richest food source is natto, a traditional Japanese fermented soybean dish, but smaller amounts are found in cheeses, kefir, and yogurt, especially those made from grass-fed dairy.

Calcium is abundant in both plant and animal foods, including leafy greens such as kale and bok choy, almonds, sesame seeds, sardines with bones, dairy products and fortified foods (like plant based milks). Choosing mineral-rich, whole-food calcium sources complements supplementation and supports strong bones and muscle function.

Combining a diet that includes these nutrient-dense foods with a well-formulated D3, K2, and calcium supplement provides comprehensive support for bone density, muscle strength, cardiovascular health, and overall vitality.

Where Can I Learn More About Menopause Remedies?

If you’re concerned about menopause symptoms or want to know more about remedies for menopause relief beyond vitamins and supplements, LifeMD is here to help.

With personalized hormone therapy, expert guidance, and support that fits your life, getting back to balance is more accessible than ever.

Join the waitlist today and take the first step toward feeling like you again.

Kerri Louati, MS, RD, LD, CDE

Kerri Louati, MS, RD, LDN, CDE, is a registered dietitian and certified diabetes educator specializing in nutrition, integrative medicine, functional laboratory interpretations, and functional medicine. She is also the Director of Women's Health Clinical Operations at LifeMD. She previously served as the Director of Nutrition and Coaching with the telehealth platform Optimal Human Health MD.

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