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Most people can get enough vitamin D from sunlight or food. However, some people may need to take a vitamin D supplement to help them get enough of this nutrient.

This article looks at who may need a vitamin D supplement, how much people need by age, and some vitamin D products to consider.

It also discusses how to get more vitamin D naturally.

Vitamin D is a fat-soluble vitamin that is essential for healthy bones, immune function, and cell growth.

Some people are more at risk of developing a vitamin D deficiency. According to the National Institutes for Health (NIH), these groups include:

  • Infants who are breastfeeding: Human milk does not contain much vitamin D. The American Academy of Pediatrics recommend that exclusively and partially breastfed infants receive 400 international units (IU) (10 micrograms [mcg]) of vitamin D per day until weaning.
  • People who get less sunlight exposure: People who are housebound, who work night shifts, or who cover their skin for religious reasons may not get the sun exposure they need to create vitamin D. People who live in colder climates may also get less sunlight exposure during the winter months.
  • Older adults: Older adults who spend a lot of time indoors may be at risk. According to the NIH, in the United States, around half of older adults with hip fractures may have inadequate vitamin D levels.
  • People with darker skin: Darker skin tones contain more melanin, which can reduce the amount of vitamin D the skin makes. However, it is unclear whether or not this has health consequences. Indeed, research suggests that Black people have fewer bone fractures and lower rates of osteoporosis than white people.
  • People with obesity: Having a body mass index (BMI) of 30 or over is associated with lower vitamin D levels. Individuals who have undergone gastric bypass surgery may also need more vitamin D.
  • People with malabsorption: Conditions such as inflammatory bowel disease affect the gut’s ability to absorb vitamin D. Additionally, people with such conditions may not be able to eat foods that contain vitamin D due to dietary restrictions.

If a person is concerned that they might not be getting enough vitamin D, a doctor can provide a blood test to confirm whether or not they have a deficiency.

Vitamin D deficiency can cause conditions that affect the bones, such as osteomalacia and rickets. However, in the U.S., most companies fortify milk with vitamin D, which has lead to rickets becoming rarer.

A person’s daily requirement for vitamin D depends on their age, whether or not they are pregnant, and whether or not they have any underlying medical conditions.

The NIH provide a general guideline as follows:

AgeDosage
0–12 months400 IU (10 mcg)
1–17 years600 IU (15 mcg)
18–70 years600 IU (15 mcg)
70 years and over800 IU (20 mcg)

People who are pregnant or breastfeeding should get 600 IU (15 mcg) of vitamin D per day.

Most people meet at least some of their vitamin D requirements by having safe exposure to sunlight. According to the NIH, spending 5–30 minutes in the sun — with the face, arms, legs, or back exposed — at least twice per week is enough.

For more in-depth resources about vitamins, minerals, and supplements, visit our dedicated hub.

Vitamin D supplements are available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol). Both are effective, but at high dosages, D3 seems to be more effective.

Manufacturers use yeast to make D2, while vitamin D3 can come from several sources, including:

  • lanolin, which comes from sheep’s wool
  • fish oils, such as cod liver oil
  • algae oil, which is suitable for vegans

Vitamin D supplements are available in different forms, including chewable tablets, liquids, and sprays. The type of supplement a person uses will depend on their preferences and medical needs. For example, a liquid or spray may be easier to swallow than pills.

The following brands or products:

Please note that the statements below are research-based. No one at Medical News Today, including the writer, has tried these products.

Vital Choice Wild Sockeye Salmon Oil & Vitamin D3

This product contains vitamin D3 from lanolin, as well as wild salmon oil, which is a good source of omega-3 fatty acids.

Three capsules provide 3,000 IU (75 mcg) of vitamin D3, giving adults more than enough of this nutrient per day. However, a person can take fewer capsules if they want or need a lower dose.

This product is NSF Certified for Sport, which means that it has undergone testing for contaminants and banned substances and that the manufacturers meet cGMP standards.

Vital Choice Wild Sockeye Salmon Oil & Vitamin D3 is available for purchase online here.

NOW Supplements Liquid Vitamin D3

This liquid vitamin D product contains 100 IU (2.5 mcg) of vitamin D3 per drop. Six drops would provide an adult with the recommended daily amount of vitamin D.

According to the manufacturers, this supplement is also suitable for children at safe dosages.

This brand has certifications from Underwriters Laboratories (UL), who run the UL National Brand Certification Program. This means that the company’s manufacturing, packaging, and warehousing practices are safe.

NOW Supplements Liquid Vitamin D3 is available for purchase online here.

Designs for Health Hi-Po Emulsi-D3

The Designs for Health website says that this supplement is highly concentrated and bioavailable, meaning that it is easy for the body to absorb. It contains 2,000 IU (50 mcg) of vitamin D in each drop, which quickly disperses in liquid.

A person can add this product to drinks or put it on their tongue. However, because this product is high strength, it is important not to take too much. A doctor can advise on the right dosage.

All Designs for Health facilities have one or more certifications from organizations such as the Natural Products Association, who enforce strict quality standards for supplements.

Designs for Health Hi-Po Emulsi-D3 is available for purchase online here.

Taking high amounts of vitamin D orally can be toxic. Research suggests that the tolerable upper limit for adults is 4,000 IU (100 mcg) per day.

Symptoms of vitamin D toxicity include:

  • anorexia
  • weight loss
  • frequent urination
  • heart arrhythmias

It is important to note that this usually only happens through supplementation. Spending a lot of time in the sun does not result in vitamin D toxicity, and it is unlikely that a person will get too much vitamin D from food.

Vitamin D supplements can also react with certain medications, such as steroids, weight loss drugs, and medications that lower cholesterol. Therefore, a person should always check with their doctor before taking a new supplement.

Having safe exposure to sunlight is one of the most effective ways to get more vitamin D.

However, if this is not possible, some foods also contain this nutrient, including:

  • oily fish, such as salmon or mackerel
  • mushrooms grown under UV light
  • beef liver
  • egg yolks
  • fortified milk
  • fortified breakfast cereals
  • fortified orange juice

A person cannot get vitamin D by sitting near windows or by sitting outside in the shade.

A person should see their doctor if they notice any of the following symptoms, as they could indicate a vitamin D deficiency:

  • bone pain
  • muscle weakness
  • fatigue
  • frequent colds and infections
  • fractures
  • depression
  • slow wound healing

If a person experiences any new or worsening symptoms after taking a vitamin D supplement, they should stop using the product and see a doctor immediately.

Having a small amount of safe sunlight exposure several times per week can help a person get enough vitamin D. However, there are a variety of reasons that a person may not be able to do this.

For some people, a vitamin D supplement may be necessary.

Vitamin D liquids allow people to tailor the dosage to their needs. Some people may only need supplements during the winter months, while others may need them year-round.

A doctor can perform a blood test to determine whether or not someone has a deficiency. They can then advise on the right dosage depending on a person’s age and any medications they take.