Tips for Buying Vitamin D
D2 or D3?
The best form of vitamin D as a supplement for adults and children is vitamin D3 or cholecalciferol, because this is identical to the kind your own body makes in your skin.
Your body can also absorb vitamin D2, which is produced by certain yeasts, algae and fungi. The algae find their way into our food chain, via fish. But fish may have found a way to convert vitamin D2 into vitamin D3, because we only find vitamin D3 in fish.
Edible fungi (mushrooms) produce substantial amounts of vitamin D2, but only if exposed to sunlight. See vitamin D sources.
- Vitamin D3 has a much greater effect on our bodies than vitamin D2
- Vitamin D3 lasts longer in our bodies than vitamin D2
An in-depth report published in the American Journal of Clinical Nutrition concluded that
Vitamin D2, or ergocalciferol, should not be regarded as a nutrient suitable for supplementation or fortification.
If your vitamin D capsules just say Vitamin D, you may only be getting vitamin D2 (ergocalciferol). So, as with all supplements, rather buy a vitamin D product which is specific about what it contains, and it should say vitamin D3.
Another advantage is that vitamin D3 supplements are generally much cheaper than vitamin D2, which is a patented product.
Capsule need not provide your exact daily dose
The daily dose for vitamin D varies from person to person, depending on body mass, sunlight-exposure and other factors. Find your dosage on our unique vitamin D dosage page.
Your body stores vitamin D, so you don’t have to take it every day. This allows you to select a capsule containing more vitamin D than you need for one day, which may work out less expensive.
For example, if the dose you want is 3500 IU per day, you could buy 5000 IU capsules, and take one capsule every day from Monday to Friday, then skip the weekend. That works out at 25000 IU per week, or 3571 per day, which is close enough.
How close should you get to your calculated target dose? Within 10% is acceptable.
It is easier to remember what to take if you do the same thing every week. Try to be consistent so you can be sure how much vitamin D3 you are taking. If in future you need to adjust your dose up or down (because a blood test shows you are above or below the target range) you will want to be certain what your starting point was.
You may choose to buy smaller-dose capsules, say 1000 IU, especially if you have children who need a smaller amount. Then each family member can take a different number of capsules, to match their personal requirement.
Unless there is a medical reason, it is not a good idea to take very large doses, such as 150,000 IU once a month. It will work, but your body is best adapted to receive frequent vitamin D, in amounts not exceeding 10,000-20,000 IU per day.
Drops for babies, please Mum
For infants and very young children, the best form of vitamin D is drops (either 400 IU or 1000 IU per drop) because drops are so easy for little ones.
You can add drops to feed, or place on a teat or pacifier or finger. Vitamin D drops don’t taste of anything, so your baby won’t mind.
For children and adults, capsules or tablets are easiest.
Vitamin D capsules are better than tablets
Because it is oil-soluble, vitamin D is most reliably absorbed from oil-filled capsules rather than tablets.
In fact, some doctors have reported that vitamin D tablets are less effective than capsules at raising their patients’ vitamin D blood levels.
So we recommend capsules for adults and children. Capsules may also be described as softgels or caps. All good.
Vegicaps are a little more expensive, and may be worth paying for if you don’t like your capsules derived from animal-based gelatin.
Shelflife of vitamin D capsules and tablets
Vitamin D tablets and capsules will generally be marked for expiry 3 years from date of manufacture.
Vitamin D capsules are oil-filled. The oil can turn rancid if not well stored, or if it is too old. Vitamin D capsules should not have an unpleasant smell.
For maximum shelf-life, store them in a cool, preferably dark place. I keep unopened bottles in the fridge. After that, they live in my cupboard.
Choose a reputable brand of vitamin D
Most manufacturers buy their bulk vitamin D from the same sources, so there is little justification for one brand costing twice as much as another.
Your main concern with buying vitamin D3 is that you get the quantity of vitamin D you are paying for. You don’t want substantially more or less than is on the label. And every dose should provide the same amount, consistently.
With a reputable brand, you can be sure of getting the stated quantity of high-quality vitamin D3 in each capsule or drop, in a suitable oil-base for maximum absorption.
All major brands take great care to meet these criteria, so if you are choosing a well-known brand, there is little to be gained from paying more than you need to.
If you use our product comparison table, we only include brands we trust.
This table contains trusted vitamin D3 products for you to compare. The Value column shows how we rate each product on Value For Money. We also show both Amazon and IHerb prices, which were correct as we went to press.
Click on the Amazon or IHerb link to confirm the selling price, make a purchase, or find out more about the product.
Vitamin D Product Comparison Table
|Now Foods||Vitamin-D3||5000 IU||Softgels||240||4.7||4.7||3.5||$25.99||$10.22||$12.70||Amazon||iHerb|
|Nutrigold||Vitamin D3||5000 IU||Softgels||360||4.7||n/a||4.5||$32.95||$16.21||n/a||Amazon||n/a|
|Drs Best||Vitamin D3||5000 IU||Softgels||360||4.5||4.4||5.0||$20.99||$13.07||$11.99||Amazon||iHerb|
|Solgar||Vitamin D3||5000 IU||Softgels||100||5.0||4.8||2.5||$11.98||$11.98||$11.98||Amazon||iHerb|
|Source Naturals||Vitamin D3||2000 IU||Capsules||200||4.7||4.8||4.0||$13.98||$6.59||$8.95||Amazon||iHerb|
|Now Foods||Vitamin D3||2000 IU||Softgels||240||4.7||4.7||3.5||$16.99||$7.46||$9.38||Amazon||iHerb|
|Bluebonnet||Vitamin D3||2000 IU||Vegicaps||180||4.9||4.9||2.5||$17.95||$14.32||$24.76||Amazon||iHerb|
* iHerb prices not automatically updated, so may not be current.