August 24, 2023

Which Vitamin D Supplement Is Best?

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Written By

Patrick Sullivan

photo of Alex Antoniou, MD

Medically Reviewed By

Alex Antoniou, MD

Lifeforce Physician

Which Vitamin D Supplement Is Best?

You need sunlight to live, and we’re not talking about getting a tan or growing a garden. More specifically, you need the vitamin D that sunlight triggers your body to produce — that’s why it’s often known as the sunshine vitamin. But, if you’re like nearly four in 10 Americans, you probably don’t get enough.

Vitamin D helps your body absorb calcium and phosphates, and grow healthy bones. Not getting enough of this fat-soluble vitamin can lead to soft, brittle, painful bones, as well as fatigue, muscle aches, pain, and mood changes. Here’s the catch, though: There aren’t a lot of natural sources of vitamin D. 

Your body makes vitamin D when it’s exposed to ultraviolet-B (UVB) rays from the sun, but it’s hard to get enough if:

  • It’s winter. 

  • You have dark skin. 

  • It’s cloudy out. 

  • You’re indoors a lot. 

  • You’re an older adult. 

  • ...and several other reasons.

Foods High in Vitamin D

There are very few foods that are high in vitamin D. These include:

  • Egg yolks

  • Fatty fish

  • Organ meats, like liver

  • ...and not much else.

Some foods, such as milk and many breakfast cereals, have vitamin D added (look for the word “fortified” on the packaging), but even that’s not enough to get many people up to the levels they need.

So, if you need vitamin D, but you can’t get enough from the sun, and you can’t get enough from your food, what are you supposed to do? 

That’s where vitamin D supplements come in. But while food sources are scarce, supplements have the opposite problem. A stroll down the aisles of your local vitamin shop (or Google’s results page) reveals a staggering array of vitamin D pills, tablets, sprays, suspensions and other forms of the nutrient.

But how do you know which vitamin D supplement is best? We’ll tell you what to look for, and how to decide on the best vitamin D supplement to try.

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What to Look for in a Vitamin D Supplement

Before you find the perfect vitamin D supplement for you, you’ll need to understand your options. One of the first choices you’ll have to make is whether to use a vitamin D2 supplement or a vitamin D3 supplement.
man holding vitamin d supplements

Vitamin D2 Vs. Vitamin D3

Vitamin D — both naturally occurring and in supplements — comes in two main forms: D2 and D3. Vitamin D2, also known as ergocalciferol, is found in plants, while vitamin D3 (cholecalciferol) is produced by animals, including humans. 

Most research shows a pretty clear benefit of vitamin D3 over D2. For example, one study found blood (serum) levels of vitamin D were 87% higher (and levels of fat-stored vitamin D three times higher) in people who took a vitamin D3 supplement compared to those who took a vitamin D2 supplement. 

In another study with data from more than 15,000 people, researchers compared blood levels of vitamin D after injections of D2 or D3. They found that even adding a D2 tablet to a D2 injection didn’t raise blood levels of vitamin D as high as D3 injections. 

By the way, when researchers or healthcare providers measure vitamin D levels in your blood or fat, they’re looking for a specific metabolite — the product of your body processing vitamin D. This metabolite is called 25-hydroxyvitamin D. It’s abbreviated 25(OH)D.

Pro Tip: Vitamin D is not the only nutrient that can help you meet your health goals. See our article: 3 Nutrients That Are Critical to Optimal Health to find out what else your body craves.

Delivery Method

Choosing how to take your vitamin D largely comes down to personal preference. For best results, it may be best to take vitamin D in pill form. One study compared vitamin D pills, oral liquid, and skin oil, and found that the pills increased serum 25(OH)D levels the most.

Of course, you may prefer the convenience of a spray, or have special dietary needs. You can take vitamin D supplements as: 

  • Pills, tablets, and capsules

  • High-dose pills, tablets, and capsules

  • Ingestible liquid 

  • Gummies

  • Mouth spray

  • Vegan vitamin D supplements


Do you take other supplements besides vitamin D? You might be able to cut down on the number of supplements you take by bundling your vitamin D with another supplement. Some supplements work particularly well with vitamin D, while vitamin D is added to others to make them work better (in addition to the benefits D brings on its own).

Frequent supplement combos you’ll see include: 

  • Vitamin D and vitamin K, like Lifeforce Vitamin D+K

  • Vitamin D and calcium

  • Vitamin D and fish oil

  • Multivitamins containing vitamin D

How do you know if you need other supplements? It’s best to test to be certain. The Lifeforce Diagnostic measures 40+ biomarkers, including vitamin D and hormone levels, to learn what your body needs most. Then you’ll review your results with a Lifeforce clinician to get you a personalized plan including supplements, lifestyle recommendations, and more. Learn more here!

Supplements and VitaminsWhich Vitamin D Supplement Is Best?

You’ll ultimately have to decide which vitamin D supplement is best for you, but we can help narrow down your options, based on your health goals and preferences. Below, we’ve outlined some of the more common choices, their pros and cons, and what to expect from them. 


Tablets, pills, and capsules you take by mouth are probably the most common method of vitamin D supplementation. The Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA) recommend most people get at least 600 international units (IU) — how vitamin D supplements are measured). 

You’ll find oral supplements in doses that far exceed that recommended daily allowance. Your healthcare provider may put you on a temporarily higher dose if you have a vitamin D deficiency.

Vitamin D overdose is rare, but it does happen (about 4,500 times per year in the U.S.). Overdose symptoms may include constipation, loss of appetite, nausea, and more. In cases of vitamin D toxicity, serum levels of 25(OH)D concentration often exceed 150 ng/mL (375 nmol/L). 

Pros of Vitamin D Tablets

  • Easily available

  • Inexpensive

  • Lots of choices

Cons of Vitamin D Tablets

High-Dose Tablets

Most people only need about 600 IUs of vitamin D for optimum health, but if you’re particularly low in vitamin D a healthcare professional might recommend more (typically up to 1,000 to 2,000 IU). 

Keep in mind there may be some potential side effects of vitamin D supplements in high doses (higher than 4000 IU daily). High-dose vitamin D supplementation has been associated with falls and fractures in older women, according to one randomized controlled trial published in JAMA. Another study suggests high-dose vitamin D in combination with calcium may be linked to an increased risk of kidney stones.

Pros of High-Dose Vitamin D Tablets

  • Commonly available

  • Can be useful in some circumstances

Cons of High-Dose Vitamin D Tablets

  • Unlikely to help more than lower doses

  • May be associated with health risks


Gummies might have been the only way you’d take your vitamins as a kid, but are they appropriate for adults? One study found that, compared to tablets, your body can absorb vitamin D better when it comes in gummy form. Plus, they taste great.

But according to the Cleveland Clinic, there are some tradeoffs. Because of all the extra sugar and gelatin in gummy vitamins, it can be hard to get enough actual vitamin into the gummies. They also degrade faster than pills and become less effective the longer they’re left sitting around.

Pros of Vitamin D Gummies

  • Effective

  • Tastes good

Cons of Vitamin D Gummies

  • Shorter shelf life

  • Less potent over time

  • Potential for overdose if you eat them for the taste


Vitamin D liquid can be a good choice for babies and children, as well as anyone who struggles with (or just doesn’t like) taking pills. Keep in mind that babies under one year only need 400 IU. Additionally, one study suggests taking liquid vitamin D under the tongue can be an effective alternative for people who can’t absorb the nutrient well in pill form.

Pros of Vitamin D Liquid

  • Good for babies and small children

  • Alternative to pills

Cons of Vitamin D Liquid

  • Fewer choices 


One delivery method that’s gaining traction is an oral spray form of vitamin D. It typically comes in bottles ranging from 25 ml to 60 ml. One spray usually provides the full dosage. A meta-analysis found that while oral spray is no more effective at raising the amount of vitamin D in the blood than other delivery methods, it’s no worse either.

Pros of Vitamin D Sprays

  • Easy

  • Convenient

Cons of Vitamin D Sprays

  • Expensive

Vegan Options

If you follow a vegan diet and lifestyle, you won’t have much trouble finding a vitamin D supplement that meets your needs. Although vitamin D2 is the obvious choice — plants produce it, after all — vitamin D3 can be synthesized from yeast, and can be a viable choice as well. Most vegan products are prominently labeled as such.

Pros of Plant-Based Vitamin D

  • Meets specific needs

Cons of Plant-Based Vitamin D

  • Fewer choices

Supplement Nutraceutical

Vitamin D and Vitamin K

If one vitamin helps your bones, then two might help even more. That’s the idea behind combining vitamin D and vitamin K — another fat-soluble vitamin found in leafy greens and other veggies, and purported to be heart-healthy. The two vitamins alone both help your body absorb calcium to make bone, but in combination the effects may be even stronger. 

One review of studies suggests that combining vitamin D and vitamin K leads to stronger bones (higher bone mineral density) than either supplement alone. Additionally, adding vitamin D to vitamin K supplements decreases a compound called undercarboxylated osteocalcin. This is a consequence of inadequate vitamin K intake that raises your risk of fractures and diabetes. Another review found that taking the two supplements together strengthens your bones and may be good for your heart as well.

Pros of Vitamin D and K

  • More effective for bone health than either alone

  • Protective for your heart

Cons of Vitamin D and K

  • None

Lifeforce D+K delivers one of the most bioavailable and bioactive forms of supplemental vitamin D (CELLg8® as cholecalciferol) to bolster bone health, immune, and neurological function. The addition of a vitamin K1 + K2 blend ensures that calcium is deposited in the bone, versus the soft tissue, for maximum results.

Vitamin D and Calcium

Vitamin K and calcium are perfect for each other. Calcium builds strong bones, and vitamin D helps your body use calcium more effectively, so it stands to reason that combining the two can be particularly effective. One study found that combining the two supplements decreased levels of parathyroid hormone, which extracts calcium from bones and can weaken them. Combining the supplements also decreases the amount of calcium in your urine. 

Pros of Vitamin D and Calcium

  • Great for your bones

Cons of Vitamin D and Calcium

  • Can cause an excess of calcium and symptoms such as constipation, nausea, vomiting, and loss of appetite

Vitamin D and Fish Oil

Vitamin D and fish oil is another supplement combination that works well. Fish oil contains omega-3 fatty acids. According to the National Center for Complementary and Integrative Health, these may reduce your levels of triglycerides (which can cause heart disease). They may also help relieve the symptoms of rheumatoid arthritis, and may modestly decrease your blood pressure. 

Interestingly, fish oil may also help your body absorb vitamin D better, per a study of people with chronic kidney disease. 

Pros of Vitamin D and Fish Oil

  • Lowers blood pressure and triglycerides

  • May help vitamin D work more effectively

Cons of Vitamin D and Fish Oil

  • May cause mild side effects such as fishy aftertaste, bad breath, or gastrointestinal upset

Pro Tip: Want to know what foods to buy to get your omega-3 levels where you need them, and what else to toss in your shopping cart to do your body right? Read our article: Top Foods to Add to Your Grocery List, According to Longevity Experts.

Do You Need Vitamin D Supplements?

So now you know the benefits of vitamin D, and you know how to choose a supplement. But do you really need vitamin D supplements? First, you’ll want to understand if your levels are out of balance. That means a trip to the doctor or a registered dietician for some blood work (or an at-home blood draw like the Lifeforce Diagnostic).

Recommendations vary, but generally if your levels of 25(OH)D are between 20 and 50 ng/mL (nanograms per milliliter), you aren’t vitamin D deficient. If your levels are lower than 20 or 30, your doctor will probably recommend supplementation.

Risk factors for vitamin D deficiency include: 

  • Over age 65

  • African American or Hispanic

  • Obesity

  • Osteoporosis

  • Limited sun exposure or living in the northern hemisphere

If any of those describe you, it might not be a bad idea to get checked out. 

Deciding on the “best” vitamin D supplement is difficult and may even be impossible. But, deciding on the best vitamin D supplement for you is significantly easier. We’ve shed some light on everything you need to know about the sunshine vitamin, so catch some rays, eat your eggs, and supplement if you need to.

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85% of Lifeforce members report improved quality of life within their first three months.

Optimize your health and longevity with the Lifeforce Diagnostic blood test plus Membership, based on research in the Tony Robbins bestseller, Life Force. We’ll measure 40+ biomarkers — including vitamin D — that drive your mental and physical health. Membership includes: 

  • Biomarker testing every three months

  • Expert clinical support

  • 1-on-1 health coaching

  • Members-only hormone optimization

This article has been medically reviewed by Alex Antoniou, MD, ABNM Board Certified in Nuclear Medicine.

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