Vitamin D vs D3: What's the difference & which should you take?




Vitamin D, often nicknamed the "sunshine vitamin," plays a vital role in maintaining strong bones, supporting immune function, and promoting overall well-being. However, navigating the world of vitamin D supplements can be confusing, with terms like "vitamin D" and "vitamin D3" thrown around interchangeably. In fact, a very common question is “What is the difference between vitamin d and vitamin d3?” Here, we’ll clear the air on the key differences and guide you towards the most suitable option for your needs.


What is vitamin D?

The term "vitamin D" is a bit of a misnomer. You won't find a bottle simply labelled "vitamin D" on the pharmacy shelf. Instead, you'll encounter two main forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Often, when someone mentions "vitamin D," they're implicitly referring to vitamin D2.

 Sources of vitamin D (D2):
  • Plant sources: Wild mushrooms are a natural source of vitamin D2.
  • Fortified foods: Due to its lower production cost, vitamin D2 is the more common form found in fortified food products like milk, plant milks, or cereals.


What does vitamin D Do?


Functions and benefits:

Vitamin D, encompassing both D2 and D3, belongs to the category of fat-soluble vitamins. These vitamins play a critical role in calcium absorption, a cornerstone for healthy bones. Additionally, vitamin D supports a robust immune system, helping the body fight off infections and illnesses.


Therapeutic uses of vitamin D2:

  • Hypoparathyroidism (decreased parathyroid hormone secretion)
  • Vitamin D-resistant rickets
  • Hypophosphatemia (low blood phosphorus levels)
  • Vitamin D insufficiency What is Vitamin D3? Vitamin D3 is the other key player in the vitamin D world.


Sources of vitamin D3:

  • Animal sources like fatty fish like salmon, tuna, and mackerel are excellent sources of dietary vitamin D3. Organ meats like liver and egg yolks also contain D3.
  • The most unique feature of vitamin D3 is that our bodies can actually produce it naturally. When our skin is exposed to sunlight, it triggers the synthesis of vitamin D3.


What does vitamin D3 do?

Vitamin D3 shares similar functions and benefits with vitamin D2, including supporting bone health and immune function. However, some research suggests it might be slightly more effective in certain areas.


Therapeutic uses of vitamin D3:

  • Hypoparathyroidism
  • Vitamin D deficiency
  • Osteoporosis prevention


What is the difference between vitamin D and vitamin D3?

While both vitamin D2 and D3 serve essential functions, there are some key distinctions to consider when looking at the difference between vitamin D and vitamin D3:


Absorption and Bioavailability:

Research suggests that vitamin D3 is more readily absorbed and utilised by the body compared to vitamin D2. This translates to higher bioavailability, meaning a greater proportion of the ingested vitamin D3 gets used by the body.


Stability and Shelf Life:

Vitamin D3 is generally more stable and has a longer shelf life than vitamin D2. This makes it a preferred choice for supplements and fortified foods.


Should I take vitamin D or D3?

The decision between vitamin D2 and D3 supplements depends on several factors:


Dietary Intake of Vitamin D:

If your diet is rich in D3-containing foods like fatty fish, your baseline levels might be sufficient.


Sun Exposure Levels:

Individuals with adequate sun exposure may naturally produce enough vitamin D3, potentially reducing the need for supplementation. However, factors like location, season, and skin pigmentation can significantly impact sun-derived vitamin D production.



As we age, our bodies become less efficient at producing and absorbing vitamin D.


Underlying Health Conditions:

Individuals with certain health conditions like malabsorption disorders might benefit more from vitamin D3 due to its superior absorption.


Factors to consider before supplementing:

  • It's always best to discuss vitamin D supplementation with your doctor. They can assess your individual needs, recommend the appropriate form and dosage, and identify potential interactions with existing medications.
  • A simple blood test can determine your current vitamin D levels and guide your doctor's recommendation for supplementation. A vitamin D home test kit is a simple way to do this!


Recommended dosages and safety considerations

Recommended daily intake of vitamin D varies based on age, overall health, and individual needs. It's crucial to follow your doctor's recommendations and adhere to safe dosage guidelines to avoid potential toxicity. Vitamin D Deficiency and Its Symptoms Unfortunately, many people worldwide suffer from vitamin D deficiency. This can be due to various reasons, including limited sun exposure, inadequate dietary intake, and certain health conditions. Here are some common signs and symptoms of vitamin D deficiency:

Fatigue and Muscle Weakness:

Vitamin D plays a vital role in muscle function. Deficiency can lead to unexplained tiredness and muscle weakness.


Bone Pain:

Vitamin D is essential for proper calcium absorption, which is crucial for bone health. Deficiency can contribute to bone aches and pains.


Increased Risk of Fractures:

Chronic vitamin D deficiency weakens bones, making them more susceptible to fractures.


Delayed Wound Healing:

Vitamin D supports the immune system and plays a role in wound healing. Deficiency can slow down the healing process.


Mood Changes:

Research suggests a potential link between low vitamin D levels and symptoms of depression and anxiety.


Benefits of vitamin D supplementation

Maintaining adequate vitamin D levels through supplementation can offer a multitude of health benefits:


Stronger Bones and Reduced Osteoporosis Risk:

Vitamin D supplementation helps improve calcium absorption, leading to stronger bones and a reduced risk of osteoporosis, a condition characterised by weak and brittle bones.


Enhanced Immune Function:

Vitamin D supports a healthy immune system, potentially helping the body fight off infections and illnesses.


Improved Muscle Function:

Adequate vitamin D levels can contribute to improved muscle strength and function.


Potential Mood Regulation:

Studies suggest vitamin D supplementation might play a role in improving mood and reducing symptoms of depression.


Choosing the right vitamin D supplement

Both vitamin D2 and D3 supplements can be effective in raising vitamin D levels. However, based on the superior absorption and stability of vitamin D3, it's generally considered the preferred choice for most individuals.


Additional considerations


Vitamin D3 Dosage:

The recommended daily intake of vitamin D3 varies based on age and individual needs. It's crucial to follow your doctor's guidance and dosage recommendations.


Supplement Form:

Vitamin D3 supplements come in various forms, including capsules, soft gummies, chewable tablets, and liquid drops. Choose a form that suits your preference and ease of use.


Vitamin D is a crucial nutrient for maintaining overall health. Understanding the differences between vitamin D2 and D3 and consulting your doctor or using a simple vitamin D home test kit can help you determine the most suitable form and dosage for vitamin D supplementation. By optimising your vitamin D levels, you can support strong bones, a robust immune system, and potentially experience a range of health benefits. Remember, a balanced diet with adequate sun exposure (when possible and with appropriate precautions) can also contribute to healthy vitamin D levels

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