The Benefits of Getting Enough Vitamin D3

Why the sunshine vitamin is important

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Vitamin D3 supplements are commonly recommended for people at risk for vitamin D deficiency. Low vitamin D levels cause depression, fatigue, and muscle weakness. Over time, vitamin D deficiency can lead to weak bones, rickets in children, and osteoporosis in adults.

Nicknamed the sunshine vitamin, vitamin D is produced by the body when ultraviolet B sun rays come in contact with special receptors in the skin. However, wearing sunscreen hinders this process, leading to mild to severe vitamin D deficiency in roughly one in four Americans.

The article discusses vitamin D supplements, explores the different forms of D vitamins available, and explains why vitamin D3 supplements are superior to D2. It also details the many benefits of vitamin D3 and other ways to get more vitamin D in your diet.

Close up capsules of vitamin D3
Olga Shumitskaya / Getty Images

How Vitamin D Supplements Work

Vitamin D helps control how much calcium and phosphate you absorb from food. Calcium is essential for bone health. Phosphate is needed for healthy bones, teeth, muscles, nerves, and basic bodily functions.

Vitamin D supplements come in two forms:

  • Vitamin D2 (ergocalciferol) is naturally found in some plants. 
  • Vitamin D3 (cholecalciferol) is naturally found in animals and is produced by the skin when it’s exposed to sunlight. 

You can meet your vitamin D needs with either form. But healthcare providers generally suggest vitamin D3 supplements. That’s because it:

  • Raises your overall vitamin D level more than D2
  • Lasts longer in the body than D2

Vitamin D3 supplements are sold as capsules, soft gel tablets, gummies, and liquid drops.

Health Benefits of D3 Supplements

Research shows vitamin D3 supplements increase vitamin D levels better than D2 supplements. Vitamin D offers many health benefits. It:

  • Strengthens bones and muscles
  • Boosts immunity
  • Improves mood
  • Reduces inflammation
  • Improves heart function


Vitamin D works with calcium to support your bones. If you’re low on vitamin D, your body can’t get calcium from food. So it steals it from your bones. This leads to:

Getting more vitamin D3 from foods is helpful for improving peak bone density. That’s the maximum amount of bone tissue you reach during adulthood.

The better your bone density, the less likely you are to develop diseases (like osteoporosis) that weaken bones.


Vitamin D appears to help you build stronger muscles. Studies suggest a link between muscle strength and high vitamin D levels.

Researchers found people with more vitamin D had:

  • Leaner bodies
  • More muscle mass
  • Better muscle function


Vitamin D may help your immune system fight viruses and bacterial infections. Research suggests it helps you stave off:

COVID-19 Risk

Low vitamin D may put you at higher risk of catching COVID-19 and having severe symptoms. More research is needed to say for sure.


Low vitamin D levels may be linked to clinical depression. It’s not clear why, though. It may be that:

  • Low vitamin D causes depression
  • Or depression behaviors (e.g., poor eating habits, less time outside) cause low vitamin D

Evidence suggests raising vitamin D levels helps with depression symptoms. It may have a role in the depression treatment regimen. Larger studies are needed to understand the connection.

Anti-Inflammatory Effects

Vitamin D may affect medical conditions caused by inflammation. Low vitamin D may increase your odds of having:

Studies have suggested taking vitamin D supplements during pregnancy makes babies less likely to have asthma. Always talk to your doctor before taking any supplements during pregnancy.

Heart Health

Research suggests a lack of vitamin D may increase your chances of:

  • Heart disease
  • Stroke
  • Blood pressure
  • Heart attacks

Vitamin D3 seems to reduce the risk of heart failure. It’s believed to improve heart function in people with weak heart muscles. Again, more research is needed.

Sources of Vitamin D

The recommended dietary allowances for vitamin D are:

  • 600 IU (international units) for adults up to age 70
  • 800 IU per day for adults over 70

Most people can handle a maximum daily intake of 4,000 IU. You can increase your vitamin D levels by:

  • Taking supplements
  • Getting more sunlight
  • Eating more foods that are high in vitamin D3

It’s hard to get enough D3 through diet alone. Eating more of the foods below can help.

Dietary Sources of Vitamin D3
Beef liver 42 3 oz. 5%
Butter 9 1 Tbsp. 1%
Cereal 80 40 grams 10%
Cheese 12 1 oz. 2%
Cod liver oil 1,360 1 Tbsp. 170%
Egg yolks 44 1 yolk 6%
Fresh salmon 570 3 oz. 71%
Halibut 384 .5 fillet 48%
Mackerel 360 .5 fillet 45%
Milk, fortified 120 1 cup 15%
Sardines 46 2 fish 6%
Trout 645 3 oz. 81%
Tuna 40 3 oz. 5%
*Based on 800 IU per day.

If you’re a vegetarian or vegan, it’s harder to get enough D3 from food. Supplements may be more important for you.

You can also boost your vitamin D with foods that contain D2.

Dietary Sources of Vitamin D2
Almond, oat, or soy milk (fortified) 100-144 1 cup 13%-18%
Mushrooms (portabella) 4 .5 cup 1%
*Based on 800 IU per day.


Supplements are the easiest way to get enough vitamin D3 every day. Studies suggest they boost D3 just as well as sunlight and food.

Talk to your doctor about the benefits and best dosage for you before you start taking supplements. Be sure you’re taking a high-quality product. The FDA doesn’t oversee supplements.

To find trusted brands, look for “USP Verified” on the label. That means the U.S. Pharmacopeial Convention (a nonprofit scientific organization) has verified that:

  • Ingredients and potencies listed on the label are accurate
  • The product doesn’t contain harmful levels of contaminants
  • Your body can absorb the supplement
  • The makers followed FDA guidelines and procedures


It may seem odd that sunlight can give you vitamin D. It doesn’t do this directly. But it starts a chain reaction.

  • Ultraviolet B rays from the sun hit your skin.
  • They activate special vitamin-D receptor cells.
  • That triggers a chemical reaction that makes your cells produce vitamin D3.

Getting a little sunlight every day can help you maintain your D levels. But it’s not the safest or most reliable way to stay healthy.

If you don’t get much sun, use sunscreen regularly, or have darker skin, you likely won’t meet your vitamin D needs from the sun.

One concern is the risk of cancer from sunlight. Some experts recommend 10 to 15 minutes of unprotected exposure a few times a week to help with vitamin D levels.

But the Centers for Disease Control and Prevention (CDC) and other medical authorities say there’s no safe way to get vitamin D from the sun without increasing your skin cancer risk.

The second problem is that it’s hard to rely on sunlight. And you can’t measure how much vitamin D you’re making from the sun. It’s easier to keep track of the vitamin D in foods or supplements.

Vitamin D Deficiency

Research shows more than a billion people worldwide have a vitamin D deficiency. Symptoms include:

  • Muscle weakness and aches
  • Weak bones
  • Fatigue
  • Inflammation
  • Hair loss

The deficiency may lead to many health conditions, such as:

  • Depression
  • Hypertension (high blood pressure)
  • Arthritis
  • Eczema

It’s best to know if you have a true vitamin D deficiency before supplementing. A simple blood test can check your vitamin D levels. Your healthcare provider can order this as part of a regular check-up.

Checking Levels

The U.S. Preventive Services Task Force (USPSTF) doesn’t recommend routine vitamin D screening in adults without related symptoms. If you suspect a vitamin D deficiency, ask your healthcare provider to test your levels.


Vitamin D3 is generally safe. But it can have toxic effects if you take too much.

Excess Calcium

Too much vitamin D can make you absorb excessive amounts of calcium. That can lead to a condition called hypercalcemia, which may:

  • Weaken bones
  • Interfere with your brain and heart
  • Cause kidney stones

Vitamin D3 Toxicity

Some symptoms of vitamin D toxicity include:

  • Nausea
  • Vomiting
  • Muscle weakness
  • Mood changes
  • Pain
  • Confusion
  • Loss of appetite
  • Dehydration
  • Excessive urination
  • Excessive thirst

Extremely high vitamin D3 levels can lead to:

  • Kidney failure
  • Irregular heartbeat
  • Death

Toxicity problems are caused almost exclusively by supplements. It’s hard to take in that much from food. And your body doesn’t produce that much vitamin D from sunlight.


Vitamin D helps you absorb calcium and phosphate from food. Vitamin D3 is more efficient than D2. You get vitamin D from food, supplements, and sunshine.

Vitamin D is important for bone and muscle strength and immune function. It may help prevent depression, inflammatory disease, and heart disorders.

Adults under 70 should get 600 IU a day. Older adults should get 800 IU. Supplements are the most reliable way to get enough vitamin D.

Taking too much can have toxic effects. Have your healthcare provider test your levels before starting a supplement.

A Word From Verywell

If you have health conditions that could be tied to vitamin D, bring it up with your healthcare provider. It’s easy to boost levels with supplements. And that could mean feeling a lot better and being healthier down the road.

Frequently Asked Questions

  • What is the difference between vitamin D and vitamin D3?

    Vitamin D3 is a form of vitamin D. It’s called cholecalciferol. Your body takes the D3 from animal products like seafood, liver, and eggs and converts it into a usable form.

  • When should I take vitamin D3?

    Vitamin D3 is a fat-soluble vitamin. That means taking it with fat helps it absorb better. It doesn’t matter what time of day you take it, but you should eat fat-containing food at the same time.

  • Is it OK to take vitamin D3 every day?

    Yes, you can take vitamin D3 daily. Talk to your doctor about the right dosage and be sure you don’t take too much.

  • Does vitamin D3 give you energy?

    A lack of vitamin D can cause you to feel lethargic. So if you’re deficient, taking D3 supplements could, over time, help you feel more energetic. However, D3 supplements don’t provide an immediate energy boost. They won’t reduce fatigue unless you have a deficiency.

  • Who should not take vitamin D3?

    People with hyperparathyroidism, kidney disease, or high levels of calcium in the blood typically should not take vitamin D3 supplements. Certain medications can also interfere with vitamin D, including Alli (orlistat), prednisone, and water pills (thiazide diuretics). There are exceptions in some cases, so speak to your healthcare provider first. 

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Yvelette Stines
Yvelette Stines, MS, MEd, is an author, writer, and communications specialist specializing in health and wellness.