How long it takes for vitamin D3 to work, what results to expect and its natural sources

Key takeaways:

• Vitamin D3 (cholecalciferol), which is not the same as vitamin D2, is a form of vitamin D that plays important roles in the body, such as strengthening bones and maintaining nerve health. 
• Factors such as deficiency, severity, lifestyle, and co-factors influence the efficacy of vitamin D3. However, many people will feel better after a few days of taking vitamin D3 supplements, while others may see improvement in their symptoms after several weeks or months of vitamin D3 supplementation.
• Consultation with a healthcare professional is essential for accurate assessment and supplementation.

Vitamin D3, also called cholecalciferol, is a fat-soluble vitamin that plays crucial roles in the body, such as increasing the utilization of calcium from food or supplements. It’s essential for optimal bone, muscle, and nerve health and helps bolster the immune system.

Cholecalciferol is a prohormone and can be acquired from external sources such as dietary supplements or animal-based foods. This vital nutrient serves as a precursor for the hormone calcitriol, which helps regulate calcium and phosphorus levels. Therefore, it plays a crucial role in regulating various normal body processes.

Individuals with vitamin D deficiency may be prescribed vitamin D3 to supplement their diet. It’s also used with calcium to strengthen bones and prevent or treat bone conditions like rickets, osteomalacia, and osteoporosis. Deficiency of this vitamin may cause symptoms like bone loss or weak bones, fatigue and tiredness, muscle pain, and depression.

How soon will you feel better after taking vitamin D3?

Some individuals, especially those with less severe vitamin D deficiency, may feel much better after a few days to weeks of taking vitamin D3. On the other hand, others may only begin to notice positive effects after several weeks to months of consistent vitamin D3 supplementation.

Notably, cholecalciferol requires conversion into its active form, calcitriol, to become effective; thus, it does not produce immediate results.

Also, even though higher doses of this supplement act more rapidly, you may not begin to feel better immediately, especially if you have been experiencing bone, muscle, or joint pain. This is because your body's vitamin D levels typically normalize before your symptoms improve, which could take weeks to a few months.

Factors that can affect how long it takes for vitamin D3 to work for you

Several factors can influence how long it takes for vitamin D3 supplementation to produce noticeable effects, and these include:

1. The severity of deficiency

Unlike those with mild cases, individuals with severe vitamin D deficiency may not notice the vitamin's effects immediately.

2. Diet and lifestyle factors

People who regularly eat foods rich in vitamin D, such as egg yolks, fatty fish, and fortified dairy products, would experience quicker results after vitamin D3 supplementation than those who do not.

Also, people with obesity may experience delayed effects compared to individuals with lower body percentages. 

3. The presence of other medical conditions that can cause malabsorption

Certain medical conditions, such as cystic fibrosis, chronic pancreatitis with pancreatic insufficiency, biliary obstruction, sprue (gluten enteropathy), inflammatory bowel disease involving the small bowel, short bowel syndrome, and gastrointestinal surgery, can impair the body's ability to absorb and metabolize vitamin D.

People with such conditions may need a higher dose or a different type of vitamin D supplement to reach optimal levels, which delays how soon they see results.

4. Drug interactions

Medications like rifampin and isoniazid affect how long it takes for vitamin D3 to work in the body.

Rifampin is an enzyme inducer, so it can reduce the effectiveness of vitamin D3 and, consequently, delay the time it would take for the vitamin to achieve its desired effect. Isoniazid, which is an enzyme inhibitor, does the opposite.

5. Presence of vitamin D cofactors

Magnesium is an important vitamin D cofactor needed to activate vitamin D3. Therefore, its presence may enhance the action of vitamin D3 and contribute to quicker results.

The same applies to other cofactors, such as calcium and zinc, which are also essential in activating vitamin D3.

Results to expect after taking vitamin D3

Here are some of the benefits of taking vitamin D3:

• Improved bone and muscle health and function
• Reduced risk of chronic diseases such as diabetes and cancer
• Enhanced immune function
• Reduced risk of pregnancy complications such as preterm birth and low birth weight
• Mood stabilization
• Improved overall well-being and reduced risk of premature death

Vitamin D3 vs. vitamin D2: Are they the same?

Vitamin D3 and vitamin D2 represent the primary forms of vitamin D, but they’re not the same.

Vitamin D3, also termed cholecalciferol, is naturally synthesized in human skin from 7-dehydrocholesterol. It’s also obtained through the consumption of animal-based foods. On the other hand, vitamin D2, also known as ergocalciferol, is predominantly synthesized artificially and added to foods.

Though these vitamins differ in their chemical structure, they both help regulate calcium and phosphate levels and control how cells grow and develop.

Essentially, both forms of this vitamin act through the body's vitamin D receptors (VDR) to produce similar effects but to varying degrees.

A study comparing the impact of vitamin D2 and D3 supplements on blood levels revealed that D3 supplements generally increased vitamin D concentrations in the blood to a greater extent and maintained those levels for a longer duration.

How to know you need vitamin D supplementation

You shouldn’t just start taking vitamin D supplements just because you feel like it. This is because taking an excess of this vitamin can lead to toxicity (which occurs when serum 25(OH)D levels exceed 220 nmol/L), with symptoms like dehydration, vomiting, stomach discomfort, frequent urination, excessive thirst, and confusion. 

Therefore, you should consider consulting a healthcare provider who would recommend the dose of vitamin D needed.

Typical signs and symptoms of vitamin D deficiency include, but are not limited to:

• Aching bones
• Weak muscles
• Reduced appetite
• Mood changes, like sadness or depression
• Pale skin
• Weakness
• Poor quality of sleep
• Thinning hair
• Increased susceptibility to illnesses
• Impaired wound healing

If you have any of these symptoms, visit your healthcare provider for further assessment of your vitamin D levels.

This can be done by testing 25(OH)D (25-hydroxyvitamin D), also known as the cholecalciferol test or calcidiol test. This is the most accurate method for determining the vitamin D level in your bloodstream and can help your doctor determine if you need supplements.

It's important to note that the elderly, breastfed infants with dark skin, overweight people, and individuals with restricted sunlight exposure or gastrointestinal conditions such as Crohn's disease or celiac disease are at a higher risk of developing vitamin D deficiency and may also need vitamin D3 supplements.1

Natural sources of vitamin D3

Getting sun on your skin is the best way to raise your vitamin D levels naturally. Experts recommend getting anywhere from 5 to 30 minutes of direct sun exposure daily to stimulate your skin to make this vitamin.

The keyword here is "direct," as anything that interferes with the sun's rays, like glass and sunscreen, will block the vitamin D-stimulating process. Even so, you don’t want to stay too long in the sun without protection because of cancer risks. 

You can also support your body’s vitamin D production by getting it from your food. Excellent dietary sources of vitamin D include:

• Fatty fish such as tuna, sardines, and mackerel
• Egg yolk
• Dairy products (cheese, milk, yoghurt)
• Fortified breakfast cereals
• Cod liver oil

Final thoughts

Vitamin D3 is the type of vitamin D produced when sunlight hits your skin. This fat-soluble vitamin is essential for regulating bone development and strengthening the immune system. It’s also found in fatty foods like fish and fortified products. 

People with low vitamin D levels may be prescribed vitamin D supplements by their health provider. However, they might not see results for weeks until their vitamin levels have been stabilized.