Best Vitamin D3, K2 and Magnesium Supplements: Compared

Our first choice for a straightforward vitamin D3, K2 and magnesium combination is DoNotAge Pure Vitamin D3, K2 & Magnesium, provided its 5,000 IU D3 strength fits your supplement plan. It combines D3, MK-7 and magnesium L-threonate in one daily capsule without asking you to assemble three separate products.

The best choice still depends on what you need the capsule to do. A combined nutritional product, a lower-dose D3 routine and a stand-alone magnesium regimen are different purchases. This guide compares current manufacturer labels and explains how to choose between them.

We have an affiliate relationship with DoNotAge and may earn a commission from qualifying purchases through our links. The comparison is based on formulation, label information and relevant ingredient research; we have not independently laboratory-tested these products or conducted a head-to-head clinical trial.

The shortlist: compare the exact formula

Labels were checked against manufacturer information available on 17 October 2026. Choose the exact variant: two bottles with similar names can have different strengths. DoNotAge, Dr. Berg, Life Extension

1. DoNotAge: our first option for the named combination

The appeal is clear: D3, MK-7 and L-threonate in one capsule, with a named amount of each. For someone already planning an appropriate 5,000 IU D3 regimen, that can make the routine simpler and reduce the need to manage separate bottles.

The current manufacturer listing gives 125 micrograms D3, 120 micrograms MK-7 and 250 mg L-threonate. Its instruction is one capsule with the last meal of the day. The public page also describes manufacturing/quality assurances and offers different pack and purchase options.

Why we put it first

Our priority for this guide is the exact three-ingredient combination in a simple capsule. DoNotAge fits that brief directly, identifies the relevant K2 and magnesium forms, and makes the routine easy to understand. This is a formulation-fit recommendation; it is not a claim that the finished product has beaten every competitor in a clinical trial.

The dose checks that matter

The D3 strength should fit your plan. It is above the general adult upper intake level of 4,000 IU, so it should not be treated as a universal low-dose maintenance amount.

Read the magnesium amount as compound weight. It is not a full 250 mg elemental-magnesium serving, and it is not equivalent to the gram-level stand-alone L-threonate regimens in sleep or cognition trials. That distinction lets you use the product for its actual purpose rather than expecting it to replace every separate magnesium regimen.

The current page states that the product is not suitable for vegans. A vegetable-cellulose capsule describes the shell, not necessarily the origin of all contents.

Our full DoNotAge D3, K2 & Magnesium review explains the 5/5 editorial recommendation, exact label amounts, current pack pricing and the research behind the formula.

View DoNotAge's current product and label. Code BB10 is supplied for a discount; check current eligibility and the final total for your market.

2. Dr. Berg: compare the strength and additional ingredients

Dr. Berg currently lists both 5,000 IU and 10,000 IU versions. The associated K2 and magnesium amounts differ, so a review that quotes one version while linking the other creates a misleading comparison.

The 5,000 IU version lists 50 micrograms MK-7 and 12.5 mg magnesium as citrate. The 10,000 IU version lists 100 micrograms MK-7 and 25 mg magnesium. The labels also include B6, zinc, MCT material and ox bile.

Those additions may be relevant to a buyer specifically seeking that formulation. They also add ingredients that should be included when checking other supplements and dietary suitability. The 10,000 IU strength is not automatically a better product because the D3 number is larger.

If the goal is a simple D3/MK-7/L-threonate combination, DoNotAge remains our first selection. If comparing the Dr. Berg options, use the exact current label and the reason for choosing that higher or more complex formulation.

3. Life Extension: a different D/K/iodine product

Life Extension's D and K with Sea-Iodine provides 5,000 IU D3, 1,000 micrograms K1, 1,000 micrograms MK-4, 100 micrograms MK-7 and 1,000 micrograms iodine per capsule.

The total vitamin K number should therefore not be read as 2,100 micrograms MK-7. It combines different K forms. Magnesium is not listed as an active nutrient, so the product does not replace the exact three-ingredient formulation considered here.

Iodine adds another decision, particularly for someone with a thyroid condition or an existing iodine-containing product. A buyer who specifically wants that D/K/iodine approach should assess it on those terms rather than comparing only the shared D3 number.

4. When separate products are the better fit

Separate products are useful if you need a lower D3 amount, need to change one nutrient independently, or want a substantial stand-alone magnesium dose without multiplying vitamin D.

They also make it easier to identify which ingredient is associated with a new symptom. The tradeoff is a more complicated routine and several labels to review.

Do not increase the number of combination capsules to imitate a stand-alone L-threonate study. Four DoNotAge capsules, for example, would multiply D3 to 20,000 IU while increasing all other ingredients. That is why dose flexibility can matter more than the apparent convenience of a larger capsule count.

Elemental magnesium: how to compare fairly

An elemental-magnesium declaration and a compound-weight declaration are different measurements. The magnesium citrate amounts in a Supplement Facts table should not be compared directly with the full mass of L-threonate compound.

In a 2026 Magtein trial, 2,000 mg compound supplied 145 mg elemental magnesium. That ratio illustrates the distinction, but does not verify the exact composition of every other L-threonate product. Ask for the relevant product specification if the elemental amount is unclear.

The dosage calculation guide provides worked examples. A good comparison uses the daily serving, elemental amount and intended outcome together.

What counts as useful quality evidence?

Look for product identity, actual potency, relevant contaminant testing and a clear link between the report and the purchased batch. A general GMP or quality-assurance statement describes a manufacturing or company commitment; it is different from a lot-specific assay.

For a certificate of analysis, check the product name, batch identifier, date, laboratory or testing party, test methods and what was actually measured. A result for one ingredient or a different lot cannot answer every question about the bottle being purchased.

DoNotAge's public quality assurances are part of the manufacturer's information. Ask the company for current batch-specific documentation if that is required for your decision. We do not convert a marketing assurance into a claim of independent testing that we have not verified.

Price, pack size and cost per day

Compare final price divided by the number of daily servings. Include shipping, taxes where applicable, subscriptions and whether a discount actually applies. A 366-capsule pack and a smaller bottle should be compared by servings, not just the checkout total.

For illustration, a 60-serving bottle costing $24 works out to $0.40 per serving. If an eligible 10% discount applied, $21.60 divided by 60 would be $0.36. These figures demonstrate the calculation; they are not a promise of a particular pack's current checkout price.

The manufacturer's page may show a “from” price or regional offer. Confirm the selected pack, currency and purchase type before calculating value. A low cost per capsule is only useful after the dose is suitable.

A decision checklist that avoids common shopping mistakes

1. Establish the intended D3 dose and include other D-containing products.
2. Confirm the K2 form and review vitamin K antagonist treatment.
3. Identify elemental magnesium and the amount per actual daily serving.
4. Check whether the desired outcome was studied with a comparable formulation and dose.
5. Review extra ingredients, dietary suitability and batch documentation.
6. Compare the final cost per appropriate daily serving.

For the named D3/MK-7/L-threonate combination, DoNotAge is our first option when its dose profile fits. For flexible dosing, select the ingredients independently. Use the main guide, dosage worksheet and safety guide to settle those questions before buying.

Research and sources

Explore the D3, K2 and magnesium research data center for study summaries, population and formulation details, limitations and original publication links. Source links throughout this guide point to the relevant evidence or official guidance.