How to Choose a Vitamin D3 and K2 Supplement
By Shop All Sports Research Supplements | Sports Research | Published: 2026-10-19
Category: How-to Guides
Learn how to pick the right vitamin D3 and K2 supplement with clear decision rules on dosage, form, and benefits for bone and heart health.
Quick Answer
To choose a vitamin D3 and K2 supplement, start by checking the dosage of both nutrients, decide between gummies and capsules based on your preference, and ensure the product uses well-absorbed forms like vitamin K2 as MK-7.
Why D3 and K2 Work Together
Vitamin D3 helps your body absorb calcium from food, but without vitamin K2, that calcium may not reach your bones and teeth. K2 activates proteins that help direct calcium to where it's needed, supporting bone health and cardiovascular function.
When shopping for a supplement, look for products that pair these two nutrients in a balanced ratio. A common approach is to choose a supplement with a higher D3 dose relative to K2, but the exact ratio depends on your individual needs.
Understanding Dosage: MCG vs IU
Vitamin D3 is often labeled in international units (IU), while vitamin K2 is typically listed in micrograms (mcg). Many supplements now show D3 in mcg as well, which can be confusing. For example, 125 mcg of D3 equals 5,000 IU, a common high-strength dose.
For K2, a typical daily dose ranges from 90 to 200 mcg. When comparing products, ensure you're comparing like-for-like units, and consider your current vitamin D status if you have recent blood work.
Gummies vs Capsules: What Matters
Both gummies and capsules can deliver effective doses of D3 and K2, but they differ in convenience and additives. Gummies are a good option if you dislike swallowing pills, but they often contain added sugars and may have a lower nutrient dose per serving.
Capsules are typically more compact and may allow for higher doses without extra ingredients. However, if you prefer a tasty, chewable option, a quality gummy like the Sports Research D3 + K2 gummies can fit your routine.
Always check the serving size—some gummies require two or more per serving, which affects the cost per day and the total supply.
Decision Rules for Choosing D3 + K2
- Check the D3 dose: Look for a D3 dose that matches your needs. If you're deficient or have low sun exposure, a higher dose like 125 mcg (5,000 IU) may be appropriate. If you're just maintaining levels, 25-50 mcg (1,000-2,000 IU) might suffice. Consider getting a blood test to know your baseline vitamin D level.
- Verify the K2 form: Choose a supplement that uses vitamin K2 as MK-7, which is more bioavailable and longer-acting than MK-4. The label should specify the form; if it doesn't, contact the manufacturer. If the form isn't listed, it's a red flag—choose a transparent brand.
- Match the form to your routine: If you struggle with pills, go for gummies. If you prefer no added sugar or need a higher dose per pill, choose capsules. Also check the number of servings per container to ensure it fits your budget and usage. Calculate the cost per day by dividing the price by the number of servings.
Product Spotlight
- 125 MCG D3 / 100 MCG K2 / 60 Gummies: Each serving of Sports Research Vitamin D3 and K2 gummies provides 125 mcg of vitamin D3 and 100 mcg of vitamin K2 in a 60-gummy bottle. This one-month supply offers a convenient way to get a high-strength D3 dose paired with a standard K2 amount, ideal for daily use.
125 MCG D3 / 100 MCG K2 / 60 Gummies
Who Should Consider This Supplement
Best for
- People with low vitamin D levels who want to support bone health
- Those who prefer a convenient gummy format for daily supplementation
Not for
- Individuals taking blood thinners or with certain medical conditions should consult a doctor before adding K2
- People who need a very high K2 dose (above 200 mcg) may need a separate supplement
