Forty-two percent of American adults are Vitamin D deficient. If you suspect you’re among them, this article is essential reading. We’ve compiled a comprehensive review of Vitamin D—what it is, its sources, and the implications of deficiency. We’ll then explore vitamin D3 supplementation, its benefits, optimal dosages, and whether D3 supplementation suits your needs. Finally, we’ll provide our unbiased recommendations for top-tier Vitamin D3 products from respected brands in the natural health space and demonstrate how you can stack D3 with calcium for enhanced results.
Vitamin D is an essential nutrient your body requires primarily for building strong bones and maintaining overall health. This fat-soluble vitamin functions like a steroid hormone in the body and comes in two forms—D2 and D3. Your skin can also produce D3 when exposed to sunlight. So, which are the best vitamin D3 supplements?
Vitamin D – The Sunshine Vitamin
Vitamin D is a fat-soluble vitamin that promotes calcium, magnesium, and phosphorus absorption, regulates bone growth, and plays a crucial role in immune function. Often called the “sunshine vitamin,” your body produces Vitamin D naturally when exposed to sunlight. You can also obtain Vitamin D through diet and supplements to maintain adequate blood levels.
Beyond supporting healthy growth and development of bones and teeth, D is believed to help resist certain diseases. Studies show that those with D deficiency face higher risks of heart disease, prostate cancer, dementia, and schizophrenia, along with the more commonly cited soft or fragile bones (osteoporosis). D also regulates cell growth, neuromuscular and immune function, and reduces chronic inflammation.
Recently published research from the University of Southampton England states there is “an indisputable relationship between vitamin D and the immune system.” Avoiding vitamin D deficiency clearly benefits immune health.
Vitamin D encompasses a family of nutrients—D1, D2, and D3—that share similar chemical structures. Typically, when we refer to Vitamin D, we mean one of the two primary forms: Vitamin D2 (ergocalciferol) or Vitamin D3 (cholecalciferol), collectively known as calciferol. Research suggests vitamin D3 is more effective than vitamin D2 at raising blood levels of vitamin D.
Vitamin D3 Comes From Animals, Vitamin D2 From Plants
These two forms of Vitamin D differ based on their food sources. Vitamin D3 is found exclusively in animal-sourced foods, while D2 primarily comes from plant sources and fortified foods.
Sources of Vitamin D3 include oily fish and fish oils, liver, egg yolk, butter, and dietary supplements. Vitamin D2 is sourced from mushrooms, manufacturer-fortified foods, and nutritional supplements.
As mentioned, your skin also produces vitamin D3 when exposed to sunlight—UVB rays trigger D3 synthesis from 7-dehydrocholesterol in your skin.
What Is Vitamin D Deficiency?
In 2014, the U.S. Preventive Services Task Force, a federally funded panel of health experts, noted there was no universal agreement on defining vitamin D deficiency or determining ideal levels. However, general guidelines exist, along with recognizable deficiency symptoms, including:
- General fatigue or feeling unwell
- Aches and pains
- Severe bone or muscle pain and weakness
- Stress fractures in legs, pelvis, or hips
Those living in densely populated metropolitan areas, spending more time indoors, or having darker skin face higher risks for lower D levels. Darker skin contains higher melanin levels, reducing Vitamin D absorption during sun exposure.
If you experience any of these symptoms, your doctor can perform a simple blood test to assess Vitamin D deficiency. For those diagnosed with deficiency, your doctor may recommend X-rays to evaluate bone strength and will likely suggest daily vitamin D supplements. 
What Are Vitamin D3 Supplements?
Vitamin D dietary supplements come as either Vitamin D2 or D3, typically in soft gel or liquid form. Less than twenty years ago, fewer than one percent of adults used a D supplement; today nearly one in five use Vitamin D daily. This increase stems from expanded awareness of D deficiency, women with osteoporosis, and our aging population. As we age, vitamin D production in our skin decreases, resulting in up to a fifty percent reduction in D3 formation.
Vitamin D3 Supplementation
While we may not know the ideal Vitamin D level, well-established guidelines exist. The National Institute of Health recommends adults consume between 400-800 international units (or 10 to 20 mcg) of vitamin D daily. Please see the chart below.
| Table 2: Recommended Dietary Allowances (RDAs) for Vitamin D [1] | ||||
| Age | Male | Female | Pregnancy | Lactation |
| 0–12 months* | 400 IU (10 mcg) |
400 IU (10 mcg) |
||
| 1–13 years | 600 IU (15 mcg) |
600 IU (15 mcg) |
||
| 14–18 years | 600 IU (15 mcg) |
600 IU (15 mcg) |
600 IU (15 mcg) |
600 IU (15 mcg) |
| 19–50 years | 600 IU (15 mcg) |
600 IU (15 mcg) |
600 IU (15 mcg) |
600 IU (15 mcg) |
| 51–70 years | 600 IU (15 mcg) |
600 IU (15 mcg) |
||
| >70 years | 800 IU (20 mcg) |
800 IU (20 mcg) |
* Adequate Intake (AI)
Reprinted from the National Institute of Health
Other field experts believe this approach is overly conservative and suggest supplementing with at least an additional one thousand IUs. Vitamin D requirements vary based on age, race, weight, and sun exposure. Current research indicates that consuming 1,000–4,000 IU (25–100 mcg) of vitamin D daily should be optimal for most people to achieve healthy vitamin D blood levels. However, we recommend not exceeding 5,000 IU of vitamin D without your doctor’s approval.
Benefits Of Vitamin D3 Supplements
Since studies indicate those deficient in Vitamin D face higher risks of heart disease, prostate cancer, dementia, and schizophrenia, some claim D3 supplementation could protect against these diseases. More recent research challenges these assumptions and reveals how little we understand about this essential nutrient. What we know definitively is that vitamin D helps our bodies absorb calcium for bone health and reduces chronic inflammation.
Other purported benefits of Vitamin D3 supplementation include improved cognition and enhanced immune health. Some manufacturers also attribute reduced risks of cancer, heart disease, diabetes, and multiple sclerosis to their structure-function claims. People deficient in vitamin D3 may also experience increased testosterone levels after supplementation.
Vitamin D3 Forms
Vitamin D supplements are either Vitamin D2 or D3 and come in soft gel capsule or liquid form. Since D3 is utilized more effectively in the body, most experts agree that D3 supplementation (cholecalciferol) is preferable to D2 (ergocalciferol).
Alternatives To D3 Supplements
We obtain Vitamin D from sunlight, nutrition, and supplementation. To prevent deficiency symptoms, the two main alternatives to vitamin D3 supplementation are adequate sun exposure and dietary sources. D-rich foods include fatty fish, fish oils, egg yolk, butter, and liver. However, obtaining sufficient Vitamin D3 from diet alone is challenging.
Does Vitamin D3 Work?
While low Vitamin D levels have been linked to numerous health problems, research on supplementation effectiveness remains inconclusive. Researchers know that vitamin D helps our bodies absorb calcium, which maintains bone health. Therefore, it’s logical to assume vitamin D supplements may strengthen bones and protect against fractures and falls.
Will Vitamin D3 Work for Me?
We suggest that if you meet the criteria for higher vitamin D3 deficiency risk—living in densely populated metropolitan areas, spending considerable time indoors, or having darker skin—supplementation is wise. If you’re experiencing any D3 deficiency symptoms, we recommend consulting your medical professional, who will likely prescribe supplementation.
Moreover, if you’re part of the Baby Boomer generation, recognize that your vitamin D3 levels have declined significantly, making supplementation essential.
Best Vitamin D3 Supplements
When selecting the best Vitamin D3 supplements, we followed these criteria:
- We ensured products are manufactured in certified cGMP facilities (Good Manufacturing Practices)
- We sought companies and brands with independent third-party testing for quality assurance
- We recommended products using appropriate 100% natural D3 forms
- We believe the appropriate dosage is 5,000 IU and our selections reflect this standard
- Price/Value – we feel quality Vitamin D3 supplements should never cost more than $15 per month’s supply
Nordic Naturals D3 Capsules
Winner of Clean Eating magazine’s Clean Choice Award. This 125 mcg (5000 IU) capsule is ideal for adults who lack adequate sun exposure. Supports healthy bones, mood, and immune system function. Nordic Naturals D3 comes in easy-to-swallow, mini soft gel size.
Package contains 120 soft gels, essentially a four-month supply, for $23.95 on the Nordic Naturals website.
Solgar Vitamin D3
Solgar has operated in the dietary supplement industry for over 70 years as a trusted source for supplements free of harmful additives and common allergens. Solgar’s Vitamin D3 5000 IU is perfect for adults wanting to supplement a wholesome diet and lifestyle that includes outdoor activities.
These soft gels are free of gluten, wheat, dairy, soy, yeast, sugar, sodium, and artificial flavors, sweeteners, preservatives, and colors.
Two hundred and forty capsules per container, $26.99 on Amazon.com.
Country Life Vitamin D3
If you’re seeking an excellent gluten-free Vitamin D3 supplement, Country Life Vitamin D3 is among our top picks. This Certified Gluten-Free supplement is also free of yeast, corn, wheat, soy, milk, salt, sugar, preservatives, and artificial ingredients. Each Non-GMO soft gel contains 5000 IU of vitamin D3 from lanolin.
Two hundred soft gels retail for $17.99 on Amazon.com.
Stacking D3 With Other Supplements
Many people combine D3 with other vitamins or minerals based on their specific needs. During flu season, an excellent combination is D3 with Vitamin C and Zinc. This trio is known to boost immunity against respiratory infections.
Another effective D3 pairing is with calcium. Here’s a combined approach:
Caltrate, Vitamin D, And Calcium
Calcium and vitamin D both support bone health. Combining these ingredients in one tablet represents a sound strategy. Beyond bone support, this combination may also promote healthy nerves, hormones, and teeth.
Two hundred tablets of this Caltrate Calcium and Vitamin D3 supplement costs $15.67 on Amazon.
To Summarize
Vitamin D3 represents one of the best values in the dietary nutrition space. The soft gel form is convenient, and the capsules are small and easy to swallow. If you meet the criteria for higher risk, exhibit any D deficiency symptoms, or are over sixty, we believe vitamin D3 is one supplement that belongs in your health arsenal. Now that you know the best vitamin D3 supplements, choose the one that’s right for you!
