uses JavaScript to provide the best possible experience for our content, but your browser has it disabled. Learn how to enable it here.


Vitamin D Review 2024
Watch the video


  • What does vitamin D do?

    There are many reasons to make sure you're getting sufficient, but not excessive, vitamin D: These include improved bone health, reduced risk of heart attack and stroke, reduced risk of asthma and allergy, reduced inflammation, possibly, a reduced risk of prostate cancer, and perhaps others. Not surprisingly, over given periods of time there are fewer deaths among people who have the right amount of vitamin D compared to those who have too little or too much. For details, see What It Does.
  • How much vitamin D do I need?

    You may already get enough vitamin D from the sun (about 15 minutes to the face, arms, and hands at least twice a week without sunscreen) and the foods you normally eat. The recommended daily allowance is 15 mcg (600 IU) for teens and adults, increasing to 20 mcg (800 IU) for those over age 70. If you're not sure, get your blood level checked by your doctor. A total serum 25-hydroxyvitamin D level of at least 20 ng/mL (equivalent to 50 nmol/L) is considered "sufficient," although there may be additional benefit to being in the 25 to 35 ng/mL range. Don't exceed 39 ng/mL. Be aware that people who are Black generally have lower total vitamin D levels than whites, but research suggests these lower levels may be sufficient for Blacks. For details see How Much Do You Need and How Much is Too Much?
  • What form of vitamin D is best?

    Vitamin D2 or D3 will raise your vitamin D level, but D3 is preferable as it may raise levels more effectively over time and is less likely to cause erroneously low vitamin D blood test results.

    Vitamin D supplements are sold as tablets, chewable tablets, capsules, gummies, softgels or liquids. Vitamin D sprays are also sold and can be as effective as a pill or liquid drops, although they tend to be more expensive.
  • Which vitamin D supplement is best?

    Among the vitamin D supplements that CL tested and Approved for Quality (see What CL Found), CL selected Top Picks based on superior quality, dosage, price, and convenience of use.
  • When to take vitamin D:

    Take vitamin D supplements with your biggest meal of the day (the one that contains most fats and oils) as this can increase absorption by as much as 50%! For details, see Take Vitamin D with Food.
  • How much vitamin D should I take?

    For every 1 ng/mL increase, you'll need to get an additional 100 IU of vitamin D per day (obese individuals may require double the amount, and if you already have an adequate level, enzymes in your body act to make it harder to raise it). For example, if your blood level is 18 ng/mL, taking 1,000 IU of vitamin D daily (or 1,600 IU if you are obese) should get you to about 28 ng/mL. It can take 6 weeks to reach the peak. Keep taking the vitamin D to stay at that level. The tolerable upper intake level (UL) of vitamin D for teens and adults, above which there is increased risk of toxicity, is 100 mcg (4,000 IU). For details, see What to Consider When Using.
  • Don't overdo it! Vitamin D safety and side effects:

    Studies show that people with the highest levels of vitamin D tend to have more bone fractures, fall more frequently, sleep less well, and die sooner than those with lower, but sufficient, levels. If your level is over 20 ng/mL, you probably don't need a supplement. If your level is above 35 ng/mL, taking a supplement may be doing more harm than good, so consider cutting back. For details see How Much Do You Need and How Much is Too Much?.

Make sure you're choosing the best vitamin D supplements approved in our tests!

See the Full Review as a Member

Join now at

Alphabetical list of vitamin D supplement brands compared in this review

View Larger Image Biotics_Research_Bio-D-Mulsion_Forte-Bone_Health-2024-small.png

Biotics Research Bio-D-Mulsion Forte

View Larger Image Carlson_Super_Daily_D3-Bone_Health-2024-small.png

Carlson Super Daily D3 2,000 IU

View Larger Image Doctors_Best_Vegan_D3_2500_IU-Bone_Health-2024-small.png

Doctor's Best Vegan D3 2,500 IU

View Larger Image Garden_of_Life_Vitamin_Code_Raw_D3-Bone_Health-2024-small.png

Garden of Life Vitamin Code Raw D3 5,000 IU (125 mcg)

View Larger Image Kirkland_Signature_D3-Bone_Health-2024-small.png

Kirkland Signature D3 50 mcg

View Larger Image Nature_Made_D3_1000_IU_25_mcg-Bone_Health-2024-small.png

Nature Made D3 1,000 IU (25 mcg)

View Larger Image Nordic_Naturals_Vitamin_D3_Gummies-Great_Wild_Berry_Taste-Bone_Health-2024-small.png

Nordic Naturals Vitamin D3 Gummies - Great Wild Berry Taste

View Larger Image NOW_High_Potency_Vitamin_D-3_2000_IU-Bone_Health-2024-small.png

NOW High Potency Vitamin D-3 2,000 IU

View Larger Image Pure_Encapsulations_Vitamin_D3_Liquid-Bone_Health-2024-small.png

Pure Encapsulations Vitamin D3 Liquid

View Larger Image Source_Naturals_Vitamin_D-3-Bone_Health-2024-small.png

Source Naturals Vitamin D-3

View Larger Image Vitacost_Vitamin_D3-Bone_Health-2024-small.png

Vitacost Vitamin D3 125 mcg (5,000 IU)

View Larger Image Whole_Earth_and_Sea_Vegan_Bioenhanced_Vitamin_D3_1000_IU-Bone_Health-2024-small.png

Whole Earth & Sea Vegan Bioenhanced Vitamin D3 1,000 IU

You must be a member to get the full test results along with's recommendations and quality ratings. You will get results for 10 vitamin D supplements selected by and two others that passed testing in its voluntary Quality Certification Program. In this comprehensive review, you'll discover:
  • Which vitamin D supplements failed our quality ratings
  • CL's Top Picks for vitamin D supplements
  • What vitamin D can and can't do for you, and how too much can actually harm you
  • How forms of vitamin D differ — including D2 and D3, as well as calcifediol and calcitriol — and which form is best for you
  • The best way to take vitamin D and how to store a bottle after opening
  • What is vitamin D deficiency and how to gauge if your vitamin D levels are sufficient, too low, or too high — and how this may differ if you are black
  • Vitamin D dosage based on your age, gender and needs
  • How to get vitamin D from the sun and from foods
  • Side effects of vitamin D supplements and potential drug interactions

Join to unlock the full report and get full access to over 1,400 reviews

See the Full Review as a Member

Join now at

Additional Information
Tested through CL's Quality Certification Program prior to, or after initial posting of this Product Review.