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Vitamin D Cofactors Supplement

5 Vitamin D Cofactors Supplement To Avoid Calcium Toxicity

by Eric Sales De Andrade, April 6th 2021

Reading Time: 7 minutes

You’ve done a blood test, checked your Vitamin D levels and found that you’re deficient and decided to take supplements.

Or you decided to take Vitamin D supplements to “stay safe” during the winter months.

Maybe you researched Vitamin D on various forums or Facebook groups and came across Vitamin D Cofactors supplement.

People talk about how you need Vitamin K, Magnesium and Boron to better absorb Vitamin D and avoid toxicity, but seems confusing, right?

How much do you take? Tablets, Capsules, Liquid — what strength?

Good news,

I’ve spoken with the experts and found the top 5 Vitamin D Cofactors supplements that will improve absorption and reduce toxicity.

The Problem With Vitamin D Supplements

When your body produces its own Vitamin D from sunlight, it is self-regulating.

This means it only produces the Vitamin D it needs and stores any excess as fat. (Vitamin D is a fat-soluble vitamin).

The body also maintains healthy levels of Calcium and magnesium levels. So all good.

However, with a Vitamin D supplement, the body loses the ability to maintain healthy levels of calcium and magnesium.

Vitamin D’s job is to provide calcium to meet the body’s needs and with high doses of Vitamin D supplements, there’s no control over where this calcium ends up.

Excess calcium in the blood (called calcification) may result in calcium deposits in arteries, brain, kidneys and other tissues contributing to heart disease and kidney failure.

Food farmed using modern agricultural practices contain only 20% of the magnesium than it did 70–100 years ago.

So you need enough magnesium to balance the excess calcium and avoid the risks associated with it.

What Are Vitamin D Cofactors?

Vitamin D Cofactors are complementary vitamins and minerals that help the body use and absorb Vitamin D while regulating the level of calcium.

High Strength Vitamin D supplements may cause a spike in calcium level leading to kidney or heart disease and Cofactors like Vitamin K2, Magnesium, Boron, Zinc and Vitamin A help regulate this and avoid calcium toxicity.

 Next, we’ll dive into each of the Vitamin D Cofactors and how much of each you need to take every day to correct a Vitamin D deficiency.

To understand what does ug mean in Vitamin D check out our other article which also contains a FREE ug to IU Calculator.

Vitamin K2 — MK7

Vitamin K2 is one of the most important Vitamin D cofactors supplement.

You’ll see a lot of Vitamin D supplements that include — D3 & K2.

Let’s look at the science behind vitamin d3 and k2 benefits and why Vitamin K2 is important.

The Science (K2)

Vitamin K2 helps keep calcium in the bones and teeth and away from critical tissues and arteries.

Its 2 main functions are:

1) Promoting calcification of bones

Vitamin K activates a protein called osteocalcin that promotes the accumulation of calcium in the bones and teeth.

2) Reducing calcification of soft tissues

Vitamin K activates a matrix GLA protein, that prevents calcium from building up and accumulating in soft tissues, such as blood vessels and kidneys.

It exists in 2 main groups

  • K1 (phylloquinone) — Found in plants like kale and spinach.
  • K2 (menaquinone) — Found in fermented foods like natto beans.

The two most important forms of Vitamin K2 are MK4 and MK7.

Vitamin K2 MK7 derived from bacteria is more likely to reach the bones and liver.

Where It’s Found? (K2)

  • Fermented foods like Natto Beans, Kefir or Yoghurt (K2)
  • Hard Cheeses and Edam (K2)
  • Kale, Spinach, Brocolli, Iceberg Lettuce, Cauliflower, and Cabbage (K1)


How Much To Take? (K2)

Dr Steven Lin, a world-leading functional dentist, TEDx speaker and author of International Best Seller “The Dental Diet” says

Taking a Vitamin D3 supplement without K2 can have disastrous effects, as Vitamin D creates need for Vitamin K2 in the body.

As a guide, you should take 45mcg of Vitamin K2 per 1000 IU of Vitamin D3.

Take 90–100 µg of K2 NK7 for 2000 IU (international units) of Vitamin D or 500 µg for a 5000 IU dose of Vitamin D.

How much Vitamin D to take depends on what your levels are right now.

Take a blood test and find out, your GP may put you on a booster dose like 30k IU or 50k IU for a week, then a maintenance dose of 2k or 4k per day.

Vitamin D Cofactors Supplement


The Science (Mg)

Magnesium is a critical mineral for your body’s well-being.

It’s needed for hundreds of biochemical reactions like protein formation, energy creation and muscle maintenance.

It also helps

  • Reduce migraines, headaches and cramps
  • Prevent sleep disorders
  • Provides insulin function for Type 2 Diabetes.
  • Prevents bone fracture

Similar to Vitamin K2, Magnesium helps remove excess calcium from the blood vessels and kidneys and maintains healthy bone health.

High levels of Vitamin D can cause depletion of Magnesium and thereby result in all sorts of health problems including an impact on your sexual health.

Vitamin D and premature ejaculation have long been a subject of study and studies found low Vitamin D contributed to premature ejaculation.

It’s highly recommended to take Vitamin D, Magnesium and Zinc together for the most optimum sexual and overall health.

Foods high in Magnesium include

Where It’s Found? (Mg)

  • Dark chocolate
  • Avocados
  • Nuts and Seeds
  • Whole grains
  • Bananas
  • Leafy vegetables (like Kale and Spinach).

How Much To Take? (Mg)

The NHS website recommends a Magnesium intake of 300mg/day for adult men and 270mg/day for adult women.

However, if you take Vitamin D supplements (particularly high doses, greater than 2000 IU) it’s recommended to take at least 500 mg of Magnesium per day.

If you feel you’re not eating enough leafy greens and food sources, it’s always best to take a Magnesium supplement.

Important Note: With magnesium supplements, check for elemental magnesium and not a compound like Magnesium Citrate.

As the latter may only contain 15 or 20% Magnesium as an element. You need to make sure you’re getting actual elemental magnesium instead of a compound.


Boron is an important element found naturally in green leafy vegetables like Kale and Spinach.

The Science (B)

Some key health benefits of Boron include

  • Reduces inflammation
  • Balances hormones (testosterone and estrogen)
  • Improves gum and teeth health
  • Fastens wound healing process
  • Prevents the chance of a Vitamin D deficiency

Let’s talk about the last point, as it’s most relevant.

Boron increases the half-life of Vitamin D and Estrogen levels in your blood.

According to Healthline,

The half-life is the amount of time it takes for a substance to break down to half its starting amount.

This means it prolongs the amount of time Vitamin D stays in your body in its most useful form.

It also plays an important role in bone and joint health.

Estrogen is a hormone that is important for bone health and a lack of it could lead to bone loss and osteoporosis.

By increase the half-life of Estrogen, Boron may help prevent osteoporosis.

Boron also activates a mineral activity called “osteoblasts” (a type of cells that helps rebuild bones).

Where It’s Found? (B)

  • Almonds
  • Beans
  • Chickpeas
  • Brazil Nuts
  • Bananas
  • Apples
  • Coffee
  • Milk
  • Potatoes

How Much To Take? (B)

While there is no specified recommended daily dose for Boron, you should be able to get most of it from the food above.

If you don’t eat much of the above, you need to get at least 3–6 mg of Boron per day via a supplement.

Omega 3

You may have heard of people taking fish oil, cod liver oil or even algae oil (the new vegan trend).


Because it’s high in Omega 3.

The Science (Omega 3)

Omega 3 is an essential fatty acid that plays an important role in improving

  • Heart health
  • Eye health
  • Brain health
  • Fight depression and anxiety
  • Reduce liver fat
  • Improves bone strength

Omega 3 improves bone strength by boosting the absorption of calcium in your bones, leading to a reduced chance of osteoporosis.

It also helps reduce the chances of arthritis.

The main forms of Omega 3 are 1) ALA and 2) DHA and EPA.

ALA is the form that’s found in foods like walnuts while EPA and DHA are found in fish oil and is the more bioavailable form.

Where It’s Found? (Omega 3)

Foods high in Omega 3 include

  • Oily fish like Mackerel, Salmon, Herring, Sardines, caviar and anchovies
  • Flaxseeds
  • Chia seeds
  • Walnuts
  • Soybeans

How Much To Take? (Omega 3)

The World Health Organization and other bodies recommend at least 500mg of Omega 3 per day for healthy adults.

If you don’t eat much of the above food, it’s best to take an Omega 3 supplement.

Vitamin A

Vitamin A is a group of fat-soluble vitamins that play a key role in many body processes and functions.

The Science (A)

There are 2 types of Vitamin A — preformed vitamin A and provitamin A.

Preformed Vitamin A is the active variant that your body can use as it is.

It’s found in meat, chicken, fish, dairy and includes the compounds retinal, retinoic acid and retinol.

Provitamin A is the inactive variant found in plants and includes compounds alpha-carotene, beta-carotene and beta-cryptoxanthin.

The inactive form of Vitamin A is converted to the active form by the body and used.

Some important benefits of Vitamin A include

  • Healthy vision and protection from night blindness
  • Aids proper growth and development
  • Protects the Immune System
  • Supports Bone Health

People with low Vitamin A levels are at a higher risk of bone fracture than people with healthy levels.

Where It’s Found? (A)

  • Liver (beef, lamb)
  • Salmon, Bluefin tuna
  • Goat cheese, cheddar, blue cheese
  • Hardboiled eggs
  • Carrots
  • Kale
  • Sweet Potato
  • Red pepper
  • Spinach

Here’s a list of 20 Foods That Are High in Vitamin A.

How Much To Take? (A)

The NHS recommends a daily intake of vitamin A for adults aged 19 to 64 need is:

  • 700 µg a day for men
  • 600 µg a day for women

You should get it all from food and the body stores excess Vitamin A as fat so you don’t need to consume it every day.

Picture of a carrot

Bringing It All Together (Vitamin D Cofactors Supplement Table)

I thought it would be helpful to include a Vitamin D Cofactor Table that you can save and review whenever you need it.

Vitamin D CoFactorWhere It's Found?How Much To Take?
Vitamin K2 (MK7)• Fermented foods like Natto
• Green feafy Vegetables
45 µg per 1000 IU of Vitamin D3
Magnesium• Dark chocolate
• Avocados
• Nuts and seeds
• Leafy vegetables
300-500 mg per day
Boron• Almonds
• Beans
• Chickpeas
• Bananas and apples
3-6 mg per day
Omega 3• Oily fish
• Flaxseeds
• Chia seeds
• Walnuts
500 mg per day
Vitamin A• Liver
• Oily fish
• Carrots, kale, spinach
700 µg a day for men
600 µg a day for women


With these Vitamin D Cofactors supplement, you’ll reduce any risk of Vitamin D toxicity from high dose supplements and give your body the best support it needs.

Take good care of yourself, because you’re worth it.

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