You eat well. You take the calcium. You do the walking. And still, somewhere in the back of your mind, you wonder whether all that calcium is actually landing where you want it. Vitamin K2 helps activate the proteins that regulate where calcium ends up in your body, which is why it sits naturally alongside vitamin D3 in a daily formula. D3 helps you absorb calcium. K2 helps direct traffic. Two tiny nutrients, one very large job.
Most people have never heard of it, because K2 is scarce in food and quiet in the body. It does not make you feel anything on Tuesday afternoon. It works on the long timeline: bone structure, artery walls, the stuff you want to still have working in twenty years. Hoola includes 5 mcg of menaquinone 7 per gram, 50 mcg per 10 g serve, and the number is published on a public register anyone can read.
Key takeaways
- Vitamin K is a family of fat-soluble compounds. It splits into K1 (phylloquinone), made by plants, and K2 (menaquinones). The most important menaquinones are MK-4 and MK-7. MK-7 is one of the most studied forms, with greater bioavailability, and it stays in the body longer.
- The scientific interest in K2 centres on bone and cardiovascular health. It plays a role in bone mineralisation and in maintaining normal bone structure. Vitamin K inadequacy may inactivate several vitamin K-dependent proteins that inhibit the formation of calcium precipitates in vessels.
- K2 activates the calcium-binding actions of matrix GLA protein and osteocalcin, two proteins that help build and maintain bones. That is why it belongs next to vitamin D3, which supports calcium absorption, bone strength, muscle and immune function.
- Hoola publishes 5 mcg of menaquinone 7 per gram and 50 mcg per 10 g serve. Look up AUST L 508472 on the public ARTG register and check the figure yourself.
- K2 is less common in the diet than K1, sitting mainly in fermented foods and certain animal products. In the average diet, about 90% of the vitamin K consumed is K1.
What is vitamin K2, and how is it different from K1?
Vitamin K2 is the menaquinone branch of the vitamin K family, and it differs from K1 in where it comes from and what it does once it is in you.
Vitamin K is not one vitamin. It is a family of fat-soluble compounds sharing a common core structure. That family exists to chemically modify a small group of proteins with calcium-binding properties, known as vitamin K dependent proteins, or Gla proteins. Two main forms matter in the diet: K1 (phylloquinone) and K2 (menaquinones).
K1 is synthesised by plants and is the predominant form in the diet. K2 is the group of compounds called menaquinones, running from MK-4 to MK-13. The naming is less mysterious than it looks. Menaquinones differ in length from 1 to 13 repeats of 5-carbon units in the side chain of the molecule. Each form is designated menaquinone-n, or MK-n, where n is the number of those 5-carbon units. So MK-7 has seven of them.
Of the menaquinones, MK-4 and MK-7 are the most important. MK-7 is one of the most studied, with greater bioavailability, and it remains in the body for longer. That is the form Hoola uses.
Both are fat-soluble, both belong to the same family, and both feed the same enzymatic machinery. They simply work differently in your body and come from different food sources. Hoola sits at the intersection of calm and capability, and this is the quiet, structural end of that: no buzz, no spike, just the parts of you that need to hold up over years.
Why does vitamin K2 matter for your bones and heart?
Because K2 is linked to bone mineralisation and to keeping calcium out of places it should not be.
Vitamin K was discovered in 1929 as an essential nutrient for blood coagulation, the scientific term for blood clotting. The name traces back to the German word Koagulation, reflecting that role in helping blood clot normally. Both K1 and K2 support healthy blood clotting, which prevents excessive bleeding and bruising when blood vessels are injured. K1 is mainly involved in supporting normal blood coagulation.
Then researchers found vitamin K-dependent proteins doing work well beyond coagulation, and identified the different isoforms of vitamin K. That shift specifically highlighted vitamin K2 as a crucial cardiovascular health nutrient. Vitamin K2 has since been the subject of growing scientific interest, particularly in relation to bone and cardiovascular health.
On the bone side, K2 plays a role in bone mineralisation and is involved in maintaining normal bone structure. On the vascular side, vitamin K inadequacy may inactivate several vitamin K-dependent proteins that inhibit the formation of calcium precipitates in vessels. Calcium in bone is the point. Calcium in a vessel wall is a problem.
Think of it as maintenance rather than performance. We do not chase intensity or burnout at Hoola. We support regulated energy, clear thinking and capability that lasts, and lasting includes the skeleton and the circulatory system carrying you around while you do it.
How does vitamin K2 work with calcium and vitamin D3?
D3 helps you absorb calcium. K2 helps activate the proteins that regulate where that calcium ends up.
Here is the mechanism in plain terms. Vitamin K acts as the switch. It carries out the post-translational modification of glutamate residues into gamma-carboxyglutamate residues, the step that builds working proteins like prothrombin. Two of the proteins carrying those carboxyglutamate residues are osteocalcin, or bone Gla protein, produced by the osteoblasts, and matrix Gla protein, or MGP. Vitamin K2 activates the calcium-binding actions of both, and they help build and maintain bones. Once the Gla residues are in place, and with calcium ions present, these proteins bind to the surface membrane phospholipids of platelets and endothelial cells, forming membrane-bound complexes with other cofactors.
Un-switched proteins cannot bind calcium. Switched proteins can. That is the whole story.
K2 has an advantage in this role. It has a long half-life and activity outside the liver, compared with the shorter half-life of the dietary form vitamin K1. Bones and arteries are outside the liver.
This is also the reason we do not sell 27 separate bottles. Hoola is designed as a single, balanced daily dose, not a collection of separate supplements, and the value sits in how the ingredients work together. Vitamin D3 supports calcium absorption, bone strength, muscle and immune function. Vitamin K2 supports bone and cardiovascular health. Manganese supports bone formation. Built in Australia, backed by science, formulated so the pieces line up.
How much vitamin K2 is in Hoola, and where can you check it?
5 mcg of menaquinone 7 per gram, and 50 mcg per 10 g serve. That is 0.05 mg of vitamin K2 a day.
You do not have to take our word for it. Hoola is a Listed Medicine on the Australian Register of Therapeutic Goods, AUST L 508472, with an ARTG start date of 8 August 2025 and Hoola Australia Pty Ltd as sponsor. The certificate lists all 27 active ingredients with exact quantities per gram. Anyone can look up AUST L 508472 on the public register and check every number. It is manufactured in Australia by BJP Laboratories Pty Ltd in Yatala, QLD, with Australian laboratory testing.
No proprietary blends. Every ingredient is delivered at a clinically efficacious dose, and every quantity is published. Every per-serve figure is the per-gram figure times ten, and both are published. Hoola uses active and bioavailable forms wherever possible, in line with Australian quality manufacturing standards.
| Active (as listed on the ARTG) | Per gram | Per 10 g serve | Supports |
|---|---|---|---|
| Withania somnifera (KSM-66 Ashwagandha), root extract | 750 mg/g dry equivalent | 7,500 mg dry equivalent | helps support the body's natural stress response |
| Bacopa monnieri (BacoMind), whole plant extract standardised | 600 mg/g dry equivalent | 6,000 mg dry equivalent | supports memory, recall and retention |
| Ganoderma lucidum (Reishi), fruiting body extract | 400 mg/g dry equivalent | 4,000 mg dry equivalent | supports healthy sleep patterns and relaxation without sedation |
| Panax ginseng (Korean ginseng), root extract | 300 mg/g dry equivalent | 3,000 mg dry equivalent | supports natural energy levels and helps reduce occasional tiredness |
| Alpinia galanga (enXtra), rhizome extract | 300 mg/g dry equivalent | 3,000 mg dry equivalent | supports mental alertness, attention and sustained focus |
| Cordyceps sinensis, fruiting body extract | 300 mg/g dry equivalent | 3,000 mg dry equivalent | supports natural energy production and helps reduce occasional tiredness and fatigue |
| Magnesium ascorbate monohydrate (vitamin C source) | 11.21 mg/g | 112.1 mg | supports normal immune function |
| Caffeine | 10 mg/g | 100 mg | supports mental alertness, reaction time and focus |
| Manganese amino acid chelate | 5 mg/g | 50 mg | supports bone formation |
| Zinc citrate dihydrate | 3.89 mg/g | 38.9 mg | supports immune function, skin health, taste and smell |
| Calcium pantothenate (vitamin B5) | 3.28 mg/g | 32.8 mg | support normal energy metabolism and the conversion of food into usable energy |
| Nicotinamide (vitamin B3) | 3 mg/g | 30 mg | support healthy skin, hair and nails (biotin, B2, B3) |
| d-alpha-tocopheryl acid succinate (vitamin E) | 2 mg/g | 20 mg | help prevent dietary vitamin and mineral deficiency |
| Pyridoxal 5-phosphate monohydrate (vitamin B6) | 1.57 mg/g | 15.7 mg | support healthy red blood cell formation (B6, B12, folate) |
| Riboflavin sodium phosphate (vitamin B2) | 1.37 mg/g | 13.7 mg | support healthy skin, hair and nails (biotin, B2, B3) |
| Thiamine nitrate (vitamin B1) | 1.23 mg/g | 12.3 mg | support normal energy metabolism and the conversion of food into usable energy |
| Betacarotene (Lyc-O-Beta) | 0.3 mg/g | 3 mg | supports vision, skin and immune function |
| Biotin | 300 mcg/g | 3,000 mcg | support healthy skin, hair and nails (biotin, B2, B3) |
| Levomefolate glucosamine (folate) | 89 mcg/g | 890 mcg | support healthy red blood cell formation (B6, B12, folate) |
| Chromium picolinate | 40 mcg/g | 400 mcg | supports healthy blood glucose within the normal range |
| Potassium iodide | 20 mcg/g | 200 mcg | supports thyroid hormone production |
| Selenomethionine | 15 mcg/g | 150 mcg | supports thyroid hormone metabolism and antioxidant defences |
| Phytomenadione (vitamin K1) | 9 mcg/g | 90 mcg | help prevent dietary vitamin and mineral deficiency |
| Molybdenum trioxide | 8 mcg/g | 80 mcg | cofactor for detoxification enzymes |
| Mecobalamin (vitamin B12) | 5 mcg/g | 50 mcg | support healthy red blood cell formation (B6, B12, folate) |
| Menaquinone 7 (vitamin K2) | 5 mcg/g | 50 mcg | supports bone and cardiovascular health |
| Colecalciferol (vitamin D3, Vitashine) | 2.5 mcg/g | 25 mcg | supports calcium absorption, bone strength, muscle and immune function |
Both K forms are in there. Vitamin K1 at 9 mcg/g and 90 mcg per serve, which is 0.09 mg. Vitamin K2 at 5 mcg/g and 50 mcg per serve, which is 0.05 mg. Vitamin D3 at 2.5 mcg/g and 25 mcg per serve, which is 0.025 mg, or 1,000 IU.
How do you get more vitamin K2 day to day?
Fermented foods and certain animal products, or a daily formula that includes it. There is not much middle ground.
The dietary problem is real. K2 is less common in the diet than K1. In the average diet, about 90% of the vitamin K consumed is K1. K1 is easy to find. It comes from plant sources like leafy greens and blueberries, and sits primarily in green leafy vegetables such as spinach, kale and broccoli. Salad handles your K1.
K2 is a different supply chain. Most menaquinones are synthesised by human intestinal microbiota and found in fermented foods and in animal products. Natto, cheese, some animal foods. If none of that is a regular fixture, your K2 intake is largely down to your gut bacteria.
On amounts, there is not yet a recommended intake set specifically for vitamin K2. Scientists studying its effects suggest the benefits come with a daily intake of between 10 and 45 micrograms.
The Hoola version is simple. Mix one 10 g scoop into 300-400 ml of cold water each morning. That is the whole ritual. There is no half serve, no double serve and no weekly total: one 10 g scoop a day. It is vegan, no sugar, gluten free, naturally flavoured, with no artificial fillers. Consistency over intensity, always. Most of our customers feel the biggest benefits with consistency, and K2 in particular is a long-game nutrient. See what is in a scoop.
Frequently asked questions
How do vitamins K1 and K2 work in the body?
Both feed the same enzyme, then part ways. The entire vitamin K family assists vitamin K-dependent carboxylase, the enzyme required to make proteins involved in blood clotting, bone metabolism and other functions. Despite that shared function, K1 and K2 have different origins in nature and take on distinct roles in the body. K2 has a long half-life and activity outside the liver, while the dietary form K1 has a shorter half-life. K1 is often filtered out of your blood within a matter of hours, whereas K2 has the potential to be longer-lasting.
Does vitamin K2 help with bone health?
Yes. Vitamin K2 supports bone and cardiovascular health. There is substantial evidence from controlled studies that K2 may provide major benefits for bone health. A 2022 meta-analysis of 16 studies in 6,425 postmenopausal women found that those taking vitamin K2 supplements had a positive effect on bone mineralisation and increased bone strength. Vitamin K insufficiency can disrupt bone mineralisation. The picture is not uniform. Intervention trials have been inconclusive on whether supplemental vitamin K, K1 or K2, further reduces bone loss in adults who already have enough calcium and vitamin D.
Is vitamin K2 good for heart health?
Yes. Research into vitamin K-dependent proteins beyond coagulation, along with the identification of the different vitamin K isoforms, has specifically highlighted vitamin K2 as a crucial cardiovascular health nutrient. Vitamin K is believed to help by preventing calcium from being deposited in your arteries. One study of 244 healthy post-menopausal Dutch women aged 55 to 65 showed substantial benefits in inhibiting age-related stiffening of arteries, with increased pulse wave velocity in the placebo group but not in the MK-7 group. A 1-year follow-up placebo-controlled, randomised clinical trial also showed cardiovascular benefit after K2 supplementation in both genders. Hoola is formulated to maintain and support cardiovascular system health and function.
Which foods contain vitamin K2?
Vitamin K2 sits mainly in animal products, fermented foods and some kinds of cheese. Most menaquinones are synthesised by human intestinal microbiota and found in fermented foods and in animal products. Relatively large amounts of menaquinones turn up in some cheeses. Most K2 sources are animal-based, though eel offers a seafood alternative.
How much vitamin K2 is in natto?
One tablespoon of natto contains 150 micrograms of vitamin K2, about twice the recommended intake. Natto is a Japanese dish made from fermented soybeans, and it holds considerable amounts of K2. One tablespoon. That is the highest-yield food option on the list, and it is also the most acquired taste.
Do fermented foods contain vitamin K2?
Yes, though the amount varies. Bacteria can synthesise the family of compounds called menaquinones, while the only important molecular form of vitamin K in plants is phylloquinone. That is why fermentation matters: the bacteria do the work. The quantity of K2 in fermented foods such as soft cheese and sauerkraut may vary according to the bacterial strains used in the fermentation.
Does cheese contain vitamin K2?
Yes. Vitamin K2 is more common in animal products, fermented foods and some kinds of cheese. Relatively large amounts of menaquinones can be found in some cheeses. Amounts vary between cheeses, since the quantity in fermented foods such as soft cheese depends on the bacterial strains used in the fermentation.
Do eggs contain vitamin K2?
Yes, eggs sit in the animal foods category where K2 is found. Vitamin K2 is found in certain animal and fermented foods and is vital for calcium metabolism and possibly cardiovascular health. Animals can synthesise MK-4 from menadione, a synthetic form of vitamin K found in poultry and swine feed.
How does vitamin K2 relate to calcium in the body?
K2 does not supply calcium. It manages it. Vitamin K2 contributes to the activation of vitamin K dependent proteins involved in the regulation and utilisation of calcium in the body. It plays a central role in calcium metabolism, calcium being the main mineral found in your bones and teeth. Two of those activated proteins are matrix GLA protein and osteocalcin, which help build and maintain bones.
Can you take vitamin K2 and vitamin D together?
Yes, and there is a logic to pairing them. Vitamin D3 supports calcium absorption, bone strength, muscle and immune function. Vitamin K2 helps activate the proteins that regulate where calcium ends up in your body. One handles the intake, the other handles the destination. Hoola includes both in a single daily dose: colecalciferol (vitamin D3, Vitashine) at 2.5 mcg/g and 25 mcg per 10 g serve, and menaquinone 7 at 5 mcg/g and 50 mcg per 10 g serve. There is no half serve, no double serve and no weekly total. One 10 g scoop a day.
Does vitamin K2 need to be taken with food?
Vitamin K is a fat-soluble vitamin, which means K vitamins dissolve in fats and oils. With Hoola, the process is fixed: mix one 10 g scoop into 300-400 ml of cold water each morning. Take it in the morning or early afternoon, and avoid it close to bedtime because of the caffeine.
What does vitamin K2 do for the body?
K2 is a fat-soluble vitamin that regulates multiple processes in the human body through the activation of vitamin K2-dependent proteins. Two of those proteins, matrix Gla and osteocalcin, play a prominent role in the function of the cardiovascular and skeletal systems. Through mechanisms that are still poorly understood, K2 also plays a significant role in the health of the digestive system, which can affect other bodily systems.
Can vitamin K2 insufficiency be measured?
Indirectly, by looking at the proteins that vitamin K is meant to switch on. The glutamate-containing, under-carboxylated precursors of the vitamin K-dependent proteins are sometimes referred to as proteins induced by vitamin K absence, or PIVKA. The glutamate precursor of prothrombin is called PIVKA-II. Vitamin K2 insufficiency is less common than vitamin K1 insufficiency, but it can occur, especially in people with poor diets or digestive complications from certain medications.
What can low vitamin K2 intake look like?
It usually starts at the plate. Poor dietary intake, particularly low consumption of vitamin K2-rich foods such as fermented foods and some animal products, can lead to insufficiency. Loading up on greens does not fully cover it, either. Some vitamin K1 can be converted into K2 by gut bacteria, but this process is limited and varies between individuals. Vitamin K insufficiency can also disrupt bone mineralisation.
What does taking vitamin K2 every day do?
Daily intake keeps activated levels steady rather than producing anything you feel. There is not yet a recommended intake set specifically for vitamin K2. Scientists studying its effects suggest the benefits come with a daily intake of between 10 and 45 micrograms. K2 is absorbed by your body more slowly than vitamin K1, which is part of what makes a daily habit sensible. That is how we build Hoola: one scoop, every morning, consistency doing the work. Read more from us.
