Vitamin D3 (Cholecalciferol): What It Is, Dose & Research

[ 01 ] Key Facts

Dose in element3	element3 Rise: 10mcg
Form	Cholecalciferol (D3) — the bioactive form identical to what skin produces from sunlight; superior to ergocalciferol (D2)
Signs you may need more	Fatigue, low mood (especially seasonal), frequent illness, bone or muscle pain, slow wound healing
Safe range	Upper intake level is typically 4,000 IU/day (100mcg). Blood levels of 25(OH)D above 50 nmol/L are considered sufficient; 75–125 nmol/L is optimal.

Food sources

Oily fish (salmon, mackerel)
Egg yolks
Fortified dairy
Cod liver oil

[ 02 ] Rationale

Why this ingredient is in element3

Vitamin D3 is not technically a vitamin — it is a hormone precursor. Once converted to its active form (calcitriol) through hydroxylation in the liver and kidneys, it binds to vitamin D receptors (VDRs) found in virtually every cell type in the body, influencing the expression of over 200 genes. This is why vitamin D deficiency has such wide-ranging consequences: it doesn’t just affect bones. It affects immune function, hormonal balance, mood regulation, inflammatory responses, and cellular health.

New Zealand has a significant vitamin D deficiency problem. Despite the country’s outdoor culture, UV intensity is insufficient for adequate D3 synthesis during autumn and winter months (April–September) across most of the country, and sunscreen use during summer further limits production. Vitamin D insufficiency is common in New Zealand, particularly through winter, with women at particular risk due to less outdoor skin exposure and higher rates of sunscreen use.

The cholecalciferol (D3) form in element3 Rise is the same molecule the body produces from sunlight, and research consistently shows it is more effective at raising and maintaining blood levels of 25(OH)D than ergocalciferol (D2), which is the plant-derived form found in some supplements and fortified foods.

Within the element3 Rise formula, D3 has a critical partnership with Vitamin K2 MK-7. Vitamin D3 enhances calcium absorption from the gut, while K2 directs that calcium to bones and teeth rather than allowing it to deposit in arteries and soft tissues. This D3/K2 pairing is one of the most well-established synergies in nutritional science — taking D3 without K2 can lead to calcium being absorbed efficiently but deposited in the wrong places. element3 Rise includes both, ensuring calcium goes where it’s needed.

D3 also interacts with the immune system at a fundamental level. It supports the innate immune response (helping macrophages and neutrophils function effectively) while supporting the adaptive immune system’s normal regulation. This dual action — enhanced defence paired with balanced response — is why D3 is consistently associated with immune resilience rather than simple immune stimulation.

[ 03 ] At 35+

Relevant at 35+

Vitamin D’s relevance intensifies after 35 on multiple fronts. Bone density begins to decline from the mid-30s, accelerating sharply during perimenopause as oestrogen’s bone-protective effects diminish. Vitamin D3 is essential for the calcium absorption that maintains bone mineral density, which is why a steady D3 intake matters more through this stage.

The hormonal shifts of perimenopause also amplify D3’s mood-related significance. Vitamin D receptors are found throughout the brain, which is part of why D3 status is of interest for mood. Keeping intake steady is a simple foundation to hold through this stage.

This is why D3 sits in element3 Rise. For New Zealand women navigating hormonal change and our seasonal UV variation, a consistent daily intake addresses a genuine and well-documented gap.

[ 04 ] Your Questions

Your Questions

What is vitamin D3?

Vitamin D3 (cholecalciferol) is a fat-soluble vitamin that functions as a prohormone — once ingested or produced in the skin from UVB sunlight exposure, it is converted by the liver to 25-hydroxyvitamin D (the storage form measured in blood tests), and then by the kidneys to 1,25-dihydroxyvitamin D (calcitriol), the biologically active hormone. In this hormone-like capacity, vitamin D3 regulates calcium and phosphorus absorption, modulates immune function, influences gene expression in virtually every tissue type, and supports mood regulation via its effects on serotonin synthesis.

What are the benefits of taking vitamin D3?

Vitamin D3 supports normal bone health through its role in calcium and phosphorus absorption, normal immune function, and normal muscle function. New Zealand's lower winter sunlight and indoor lifestyles make vitamin D insufficiency common, even in a country known for sunshine.

What are the benefits of vitamin D3 in the element³ protocol?

In element3 Rise, vitamin D3 at 10mcg (cholecalciferol) supports the hormonal, immune, and bone health benefits of the formula. Its most critical synergy is with Vitamin K2 MK-7: D3 increases calcium absorption from the gut, and K2 ensures that calcium is directed to bones rather than depositing in soft tissue and arteries. Without adequate K2, the calcium that D3 helps absorb can accumulate in the wrong places. element3 Rise delivers both together in the morning formula, reflecting how they function interdependently in the body’s calcium economy.

What is the recommended daily intake of vitamin D3?

The adequate intake for vitamin D in New Zealand is 5mcg (200 IU) per day for adults aged 19–50, rising to 10mcg (400 IU) for adults aged 51–70. element3 Rise provides 10mcg (400 IU) per serve. The upper safe intake level is 100mcg (4,000 IU) per day. Individual needs vary considerably with sun exposure, season and skin tone — blood testing for 25(OH)D is the most reliable way to determine what's right for you, and optimal levels are considered 75–125 nmol/L.

What food provides vitamin D3?

Vitamin D3 is found in relatively few foods: oily fish (salmon, mackerel, sardines, herring), egg yolks, beef liver, and cod liver oil are the primary sources. Some dairy products and plant milks are fortified with vitamin D, though often at low levels. The vast majority of human vitamin D historically came from sunlight synthesis in skin rather than diet. In New Zealand, adequate skin synthesis is possible in summer but impractical in winter months or for people who work indoors, use sunscreen, or have darker skin tones, making supplementation a practical necessity for many women.

Are there any vitamin D3 side effects?

At the dose in element3 Rise, vitamin D3 is safe and well-tolerated. Vitamin D toxicity (hypervitaminosis D) only occurs from sustained supplementation well above the upper intake level of 100mcg (4,000 IU) per day, and manifests as hypercalcaemia: nausea, weakness, frequent urination, and in severe cases kidney damage. This is not a risk from dietary or standard supplemental doses. Because vitamin D is fat-soluble and accumulates, regular blood testing is recommended for individuals taking high therapeutic doses (above 2,000 IU), though standard supplemental doses carry no meaningful accumulation risk.

What are vitamin D3 deficiency symptoms?

Vitamin D deficiency symptoms include persistent fatigue, low mood or seasonal depression, frequent illness and poor immune resilience, bone or muscle aches and pain, muscle weakness, slow wound healing, and hair loss. Because 25(OH)D blood levels can be measured directly, deficiency can be confirmed rather than guessed. Levels below 50 nmol/L indicate deficiency; 50–75 nmol/L is insufficient; above 75 nmol/L is adequate; 75–125 nmol/L is considered optimal by many practitioners. Subclinical vitamin D insufficiency is widespread in New Zealand women, particularly in winter and in women who minimise sun exposure.

What form of vitamin D is in the element³ blend?

element3 Rise uses cholecalciferol (D3) — the form of vitamin D produced naturally by human skin in response to UVB sunlight and the bioactive form found in animal food sources. D3 is the preferred form over ergocalciferol (D2), which is derived from plant sources and has lower potency and shorter duration of action in the body. Clinical research consistently shows that D3 raises blood 25(OH)D levels more effectively and sustains them longer than D2 at equivalent doses. Cholecalciferol at 10mcg (400 IU) in element3 Rise is the appropriate, well-studied form for daily supplementation.

How much vitamin D3 should I take daily?

element3 Rise provides 10mcg (400 IU) of vitamin D3 per serve. Individual needs vary with sun exposure and season, and a blood test is the most reliable guide. Your healthcare professional can advise on what's appropriate for you.

Vitamin K2 and D3 — why take them together?

Vitamin D3 enhances calcium absorption, while K2 directs that calcium to bones rather than arteries. Without K2, increased calcium absorption from D3 may contribute to arterial calcification. element3 Rise includes both D3 and K2 MK-7 to ensure calcium is absorbed and deposited correctly.

What is the difference between vitamin D2 and D3?

Vitamin D3 (cholecalciferol) is the form produced by human skin from sunlight and is more effective at raising blood vitamin D levels. Vitamin D2 (ergocalciferol) is plant-derived and less efficiently converted. element3 Rise uses D3 for maximum bioavailability.

Vitamin D3 in NZ— are New Zealanders deficient?

Yes, vitamin D deficiency is common in New Zealand. UV intensity is insufficient for adequate skin synthesis during autumn and winter (April–September), and population studies suggest 30–40% of NZ adults have insufficient levels. Supplementation is recommended, particularly during winter months.

[ 05 ] The Research

3 studies

The Research

Study	Key finding	Read
Calcium plus Vitamin D Supplementation and the Risk of FracturesJackson RD, LaCroix AZ, Gass M, et al; Women's Health Initiative Investigators. Calcium plus Vitamin D Supplementation and the Risk of Fractures. New England Journal of Medicine. 2006;354(7):669–683. doi:10.1056/NEJMoa055218. PMID: 16481635.	One of the largest clinical trials ever conducted in postmenopausal women provides direct evidence at this vitamin D dose. 36,282 postmenopausal women were randomly assigned to 1,000 mg of calcium plus 400 IU of vitamin D3 daily or placebo, over an average of 7 years. Hip bone density was 1.06 percent higher in the calcium plus vitamin D group than in the placebo group (P<0.01), a small but statistically significant improvement. Because the trial was conducted entirely in postmenopausal women, the finding is directly applicable to women in mid-life and beyond, with no extrapolation from male data. The vitamin D was given alongside calcium, reflecting vitamin D3's central role: enabling the body to absorb and use dietary calcium.	Read →
Vitamin D3 + K2 (MK-7) combination — Kanellakis et al., 2012Kanellakis S, Moschonis G, Tenta R, Schaafsma A, van den Heuvel EGHM, Papaioannou N, Lyritis G, Manios Y. Changes in Parameters of Bone Metabolism in Postmenopausal Women Following a 12-Month Intervention Period Using Dairy Products Enriched with Calcium, Vitamin D, and Phylloquinone (Vitamin K1) or Menaquinone-7 (Vitamin K2): The Postmenopausal Health Study II. Calcified Tissue International. 2012;90(4):251–262. doi:10.1007/s00223-012-9571-z. PMID: 22392526.	This 12-month randomized trial tested vitamin D3 at 10 µg (400 IU) together with vitamin K2 in the long-chain MK-7 form, in postmenopausal women. Participants received fortified dairy providing 800 mg of calcium and 400 IU of vitamin D3 daily, with two groups additionally receiving 100 µg of either vitamin K1 or menaquinone-7 (K2). Serum 25(OH)D, the marker of vitamin D status — rose significantly across all supplemented groups versus control, and serum IGF-I, a growth factor involved in bone maintenance, rose significantly in the MK-7 group. The two vitamin K groups showed more favourable changes in bone metabolism and bone-mass indices, reflected in suppressed bone-remodelling markers and more positive changes in lumbar-spine bone mineral density. Conducted in postmenopausal women, the results speak directly to bone health in this age group.	Read →
Investigating the Effects and Mechanisms of Combined Vitamin D and K Supplementation in Postmenopausal Women: An Up-to-Date Comprehensive Review of Clinical StudiesReference: Rusu ME, Bigman G, Ryan AS, Popa DS. Investigating the Effects and Mechanisms of Combined Vitamin D and K Supplementation in Postmenopausal Women: An Up-to-Date Comprehensive Review of Clinical Studies. Nutrients. 2024;16(14):2356. doi:10.3390/nu16142356. PMID: 39064799.	This 2024 review is the first to comprehensively synthesise the randomized-trial evidence for vitamin D and vitamin K taken together in postmenopausal women. Across 31 relevant randomized controlled trials, the authors concluded that combined intake of vitamins D and K may positively affect both cardiovascular and bone health in postmenopausal women, and recommended vitamin D and K supplementation to support healthy aging where diet alone falls short. It provides the broader evidence base for the rationale of pairing the two vitamins in women navigating menopause and beyond	Read →

[ 06 ] In the Protocol

Where Vitamin D3 (as Cholecalciferol) sits in the element3 Protocol

In element3 Rise (AM Formula), vitamin D3 at 10mcg (400 IU) as cholecalciferol supports normal calcium absorption, immune function and bone health. It works in partnership with Vitamin K2 MK-7, which supports the body’s normal use of calcium in bone, and complements the Selenium and Vitamin E antioxidant systems. Taken in the morning with dietary fat for absorption, it addresses one of the most common nutrient gaps in New Zealand.

You can learn more about the full element3 ingredient philosophy at element3.co.nz.

Vitamin D3 (as Cholecalciferol)