Is a Vitamin D Supplement as Good as Sunlight?

Medically Reviewed on 11/22/2021
Is a Vitamin D Supplement as Good as Sunlight
Getting vitamin D through supplements is better than through sunlight, as it helps you avoid the risk of sunburn, skin cancer, and overall skin damage

Getting vitamin D through supplements is better than getting through sunlight. Vitamin D supplements are not only the easiest way to avoid vitamin D deficiency, but they also help you avoid the risk of sun damage.

Although some self-proclaimed experts have advocated tanning in the sun to obtain vitamin D, most dermatologists are adamantly opposed to this idea. Ultraviolet B exposure during tanning, either in the sun or tanning booth, can cause sunburn and skin cancer.

What are different sources of vitamin D?

Sources of vitamin D include:

  • Sunlight
  • Foods (natural and fortified)
  • Supplements

Most people can get adequate vitamin D through diet and sun exposure. When exposed to sunlight, your skin can synthesize vitamin D3 (a subtype of vitamin D) from cholesterol. Certain foods such as salmon, tuna, mackerel, beef liver, and egg yolks are rich in both vitamins D2 and D3. Foods such as milk, cereal, and some orange juices are often fortified with vitamins D2 and D3 to help increase your vitamin D intake.

Vitamin D supplements come in a variety of doses, in both pill and liquid form and in vegetarian as well as vegan alternatives. You must consult with your doctor regarding the dose best for your condition.

Routine high dose vitamin D supplementation is only recommended for people with fat absorption issues, lactose intolerance, and milk allergies, as well as for people with darker skin tones. People with skin conditions like albinism require medications that provide increased protection from ultraviolet rays. Such individuals may also have low vitamin D levels.

Is vitamin D2 as good as vitamin D3?

Vitamins D2 and D3 are the two main forms of vitamin D. Both convert into calcifediol (calcidiol) in the liver. Calcifediol is further converted to the active form calcitriol in the kidneys.

The efficacy of vitamin D2 versus vitamin D3 has been debated. However, most studies reported that D2 yields less calcifediol than D3. Hence, in cases of known deficiencies, it is better to consume vitamin D3 rather than D2.

Depending on your vitamin D levels, your doctor may prescribe either weekly supplements of:

  • 50,000 international units (IU) D2 or D3 orally for 6-8 weeks followed by a maintenance dose of 800 IU daily, or
  • 1,000 IU of vitamin D3 daily for 6-8 weeks.

Vitamin D supplementation should be accompanied by calcium supplementation as well.

How much vitamin D do I need every day?

For most healthy people, the Recommended Daily Allowance (RDA) of vitamin D is 600 IU per day. Those over age 70 need about 800 IU. Babies need between 200-400 IU.

While low vitamin D levels can lead to poor bone and muscle health, as well as hair fall, fatigue, and increased risk of fractures, excess vitamin D levels can cause vitamin D toxicity that can progress from nausea, vomiting, and bone pain to kidney failure. Therefore, it is best to exercise caution when consuming vitamin D supplements.

Table: Blood levels of vitamin D
Diagnosis Levels of vitamin D (ng/mL) Levels of vitamin D (nmol/L)
Normal levels ≥20 ng/mL ≥50 nmol/L
Vitamin D insufficiency 12 to 20 ng/mL 30 to 50 nmol/L
Vitamin D deficiency <12 ng/mL <30 nmol/L
Vitamin D toxicity >100 ng/mL >250 nmol/mL
Levels suboptimal for bone health 20 ng/mL 50 nmol/L

Does sunscreen affect my vitamin D absorption?

High-SPF (30 or higher) sunscreens are designed to filter out most of the sun’s ultraviolet B (UVB) radiation. Theoretically, then, as UVB wavelengths are the ones that trigger vitamin D production in the skin, sunscreen should affect vitamin D absorption. However, most clinical studies have found that everyday sunscreen use does not lead to vitamin D insufficiency.

Skin exposure to UVB rays for even 10-15 minutes a day can cause DNA damage and increase your risk of developing skin cancer. Every bit of DNA damage adds up over your lifetime and produces more and more genetic mutations that increase your lifetime risk of skin cancer.

As such, it is better to continue using sunscreen and obtain your vitamin D from your diet and vitamin D supplements.


Next to red peppers, you can get the most vitamin C from ________________. See Answer
Medically Reviewed on 11/22/2021
Image Source: iStock Images