Vitamin D3 and K2 in Australia: what’s in each product, graded by a pharmacist

Written by Cassie Sanghvi, registered pharmacist
Founder of Clean Green Safe

Vitamin D3 and K2 combinations have become one of the most popular pairings on the pharmacy shelf. If you’re wondering whether one is worth adding to your routine, or which one to choose, it helps to know exactly what’s in each bottle and how it compares to what you need.

I’m a registered pharmacist, and I’ve graded the vitamin D3 and K2 products in our database. For each one I’ve checked the label against the TGA register and worked out how much of each vitamin you get a day at the dose on the pack.

Before you start: vitamin K and blood thinners

If you take warfarin, please talk to your GP or pharmacist before taking any product with vitamin K, including K2. Vitamin K works directly against warfarin, so even a small daily amount can change how well your medicine works. This doesn’t apply in the same way to newer blood thinners, but it’s still worth checking.

What are vitamin D3 and K2?

• Vitamin D3 (colecalciferol) helps your body absorb calcium. Many Australians, especially those who spend little time outdoors, have low vitamin D levels, which a simple blood test can check.
• Vitamin K is needed for normal blood clotting. K1 (phytomenadione) comes mostly from leafy greens. K2 (menaquinone) comes from fermented foods and some animal foods. Supplements usually use a form called menaquinone-7, or MK-7.
• The two are often sold together because both are involved in how your body handles calcium. A combined product is convenient, but you don’t need both to benefit from either one.

How much do you need a day?

Most vitamin D3 and K2 products give you 25 mcg (1,000 IU) of vitamin D a day. That’s well above the everyday target but comfortably under the 80 mcg upper limit, and it’s a common dose when a blood test shows your levels are low. There’s no upper limit set for vitamin K, but that doesn’t mean more is better. It simply means there isn’t enough evidence to set one.

The vitamin D3 and K2 products we’ve graded

All three earn an A. They’re clearly labelled, listed on the TGA register, and stay well under the vitamin D upper limit. The main differences are the amount of K2, and whether you’d like calcium included.

Do you need calcium with it?

Go Healthy’s product adds 260 mg of calcium, about a quarter of the 1,000 mg daily target for most adults. Most Australians get a good share of their calcium from food, especially dairy, so it’s worth looking at your diet before adding a calcium supplement. If you already take calcium separately, a product without it avoids doubling up.

Already taking a multivitamin?

Many multivitamins already contain vitamin D and vitamin K, usually as K1 rather than K2. Adding a D3 and K2 product on top can push your total vitamin D higher than you might expect. It’s worth adding up what’s in everything you take before buying something new.

Getting the most from your vitamin D3 and K2

• Both vitamins dissolve in fat, so take them with a meal that contains some fat, such as breakfast with eggs, yoghurt or avocado.
• Pick a time you’ll remember every day. Keeping the bottle beside your breakfast things is an easy reminder.
• If you’re taking vitamin D because a blood test showed low levels, ask your GP when to have it checked again.

Questions people often ask

This article is general information and isn’t a substitute for advice from your own GP or pharmacist, who can take your health history, medicines and blood results into account.

ABOUT THE AUTHOR

Cassie Sanghvi, registered pharmacist

Cassie Sanghvi is a registered pharmacist, a parent and the founder of Clean Green Safe. With a background in Australian supplement regulation across the TGA, FSANZ and NHMRC, she built Clean Green Safe to help people understand what’s really in their supplements, and how it all adds up across everything they take.