• Optivida Organic Vitamin D3 4,000 IU with magnesium
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Optivida Organic Vitamin D3 4,000 IU | Algae-Derived + Magnesium

Optivida Organic Vitamin D3 4,000 IU | Algae-Derived + Magnesium

Plant-based D3 for the vitamin D winter

4,000 IU of vitamin D3 from organic algae, with magnesium and an absorption blend of enzymes and probiotics. North of about 40° latitude, there are months when winter sun can't make enough vitamin D for anyone (Nutrients, 2024).*

Supports normal immune function, bones and muscles*

60 capsules · 2 capsules daily · 30-day supply

Vegan · Non-GMO · Gluten free · Made in the USA · Free US shipping

$21.95 USD
$21.95 USD
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How to use

Take 2 capsules daily, ideally with a meal. Store tightly closed in a cool, dry place. If you take medication, other vitamin D products, or are pregnant or nursing, check with your healthcare practitioner first.

Optivida Organic Vitamin D3 4,000 IU | Algae-Derived + Magnesium

A 36-year-old discovery

In 1988, a scientist put the winter sun to the test. It failed.

Ann Webb and her colleagues set out vials of the compound your skin uses to make vitamin D under the Boston sky, month after month. From November through February, the sunlight made none. Not on cold days. Not on bright, clear ones.

In 2024, Webb's team looked again, this time with 16 years of satellite measurements covering the entire planet. The result held: above about 40° latitude, there are months when no one can make enough vitamin D from sunlight, whatever their skin type. Researchers call it the vitamin D winter.

Living farther south doesn't get you off the hook. A second 2024 team modeled the latitudes of San Francisco and Washington, DC. In November, December and January, the vitamin D-making sunlight was gone.

So between Halloween and Valentine's Day, where is your vitamin D coming from?

40°N
and north
Some months, no one can make enough vitamin D from sun.

Boston · New York · Philadelphia · Chicago · Salt Lake City · Minneapolis · Seattle

Kift & Webb, Nutrients, 2024

37–41°N
Vitamin D-making sunlight was absent in Nov, Dec and Jan, and almost none in Oct and Feb.
JFMAMJJASOND

None Almost none Active

Same latitude as San Francisco · Sacramento · Denver · Kansas City · St. Louis · Washington, DC

Kallioğlu et al., Scientific Reports, 2024 (modeled at 37°N and 41°N)

4,000 IUvitamin D3 (100 mcg) per serving
42 mgmagnesium, as gentle bisglycinate
+77%average rise in blood vitamin D in 7 days†
30servings, a 1-month supply

† Human study of the algae D3 ingredient (600 IU/day, 10 adults), AnaBio Technologies & University College Dublin, 2020.

Even when the sun is out

Sunlight alone is a shaky plan for most of us.

  • 1
    The sun sits lowerIn fall and winter the sun's angle is too low for much vitamin D-making UVB to reach you, even on clear days.
  • 2
    We live indoorsShorter days and colder weather mean less time outside, and more skin covered when we are.
  • 3
    It changes with ageSkin makes less vitamin D as we get older, so the same hour of sun gives you less than it did at 25.
  • 4
    Food falls shortVery few foods naturally contain much vitamin D, so most people can't reach their needs from diet alone.
The sun's path is high in summer and much lower in winter, which means less vitamin D-making sunlight. Summer sun Winter sun Lower sun = less UVB = less vitamin D made in skin

What vitamin D does

One vitamin, four big jobs.

Immune support

Supports the normal function of your immune system.*

Strong bones

Helps your body absorb calcium to keep bones and teeth strong.*

Muscles

Supports normal muscle function and strength.*

Year-round

Helps you keep healthy vitamin D levels when sunlight is scarce.*

Inside every serving

Not just D3. The team that helps it work.

Your body has to convert vitamin D into its active form before it can use it, and magnesium is part of that process. So Optivida built the formula as three parts.*

The vitamin
4,000 IU

Vitamin D3 from organic algae

Cholecalciferol, the same form your skin makes from sunlight. Most D3 comes from lanolin (sheep's wool oil); ours comes from algae, so it's fully vegan.

The helper
42 mg

Magnesium bisglycinate

A chelated, easy-to-absorb form of magnesium (Albion® TRACCS®). Magnesium helps your body activate and use vitamin D.*

The support crew
681 mg

Optivida absorption blend

Organic gum acacia, a broad set of digestive enzymes, and probiotic strains including Lactobacillus and Bifidobacterium, to support healthy digestion and nutrient absorption.*

The science

Tested in people, not just in a lab.

The plant-based D3 in this formula was given to healthy adults who hadn't taken vitamin D in the past year. Their blood was tested before and after one week.

Vitamin D3V® Human Intervention Bioavailability Trial

AnaBio Technologies Ltd with University College Dublin, Ireland, 2020. Blood levels of 25-hydroxyvitamin D measured on day 0 and day 7.

Average blood vitamin D, before and after 7 days +77% 600 IU a day of the algae D3 ingredient

The study at a glance

Who10 healthy, active adults, 18–65
Dose600 IU a day
How long7 days
Average level, day 043.4 nmol/L
Average level, day 777 nmol/L
Result+77%, statistically significant (p = 0.002)

What those numbers mean

Commonly used ranges for blood vitamin D, from the study report:

Under 25Deficient
25–50Insufficient · day 0 average
50–70Normal / sufficient
70–80Optimal · day 7 average

A small study of the D3 ingredient at a lower dose than Optivida's 4,000 IU serving; it did not test the finished capsule. Ranges are in nmol/L (divide by 2.5 for ng/mL). Individual results vary.

Read the label

Clean, plant-based, and clearly labeled.

  • ✓
    4,000 IU vitamin D3 per serving2 capsules, from an organic algal source.
  • ✓
    42 mg magnesiumAs magnesium bisglycinate chelate.
  • ✓
    No added yeast, wheat, milk, egg or soyAnd no sugar, artificial color or preservatives. Vegan, non-GMO, gluten free.
  • ✓
    Made in the USASold by Honest Nutrition, an authorized Optivida distributor.

Supplement Facts

Serving size 2 capsules · 30 servings per container
Amount per serving%DV
Vitamin D3 (organic algal source)4,000 IU (100 mcg)500%
Magnesium (magnesium bisglycinate chelate)42 mg10%
Proprietary Optivida Absorption Blend681 mg††
Organic gum acacia, amylase I, protease I, lipase, lactase, protease II, protease III, serratiopeptidase, amylase II, bromelain, papain, HemiSEB™, dipeptidyl peptidase, cellulase, alpha galactosidase, glucoamylase, invertase, phytase, Bacillus coagulans, Bacillus subtilis, Bacillus clausii, Lactobacillus acidophilus, L. plantarum, L. salivarius, L. casei, L. rhamnosus, L. brevis, Bifidobacterium breve, B. bifidum, Streptococcus thermophilus, B. lactis/longum

†† Daily Value not established. Other ingredients: non-GMO plant cellulose (capsule), organic rice flour. Always refer to the label on your bottle.

How to take it

Two capsules a day. That's it.

Daily amount2 capsules
Best withA meal
One bottle lasts30 days
Cost per dayabout $0.73
ShippingFree to any US address
Cold & flu season pairing

Vitamin D3 + Vitamin C

Both support normal immune function. Optivida's Vitamin C is whole organic acerola cherry, 140 mg per capsule, with no synthetic ascorbic acid.*

See Organic Vitamin C →

Tip: vitamin D is fat-soluble, so taking it with a meal that has a little fat in it is a good habit.

Questions

Good to know

What's the difference between vitamin D2 and D3?

D3 (cholecalciferol) is the form your own skin makes from sunlight. D2 usually comes from mushrooms or yeast. Most D3 is made from lanolin, an oil from sheep's wool. Optivida's D3 comes from organic algae, so you get the D3 form in a fully plant-based capsule.

Why is magnesium in it?

Your body converts vitamin D into its active form in steps, and magnesium helps with that process. The formula includes 42 mg of magnesium as bisglycinate, a form that's well absorbed and gentle on the stomach.*

Is 4,000 IU a day a lot?

4,000 IU is the daily upper intake level the National Institutes of Health sets for adults, so this serving stays within it. If you also take a multivitamin or Complete Essentials, count the vitamin D in those too, and ask your healthcare practitioner what's right for you.

When should I take it?

Two capsules a day, ideally with a meal. Many people take it with breakfast or lunch so it becomes part of the routine.

Is it vegan?

Yes. The D3 comes from algae, the capsule is plant cellulose, and there are no animal ingredients. It's also non-GMO and gluten free.

How long will it stay fresh?

Keep the bottle tightly closed in a cool, dry place. The probiotics are the most sensitive part, so heat and humidity are what to avoid.

I take medication. Can I use it?

Check with your healthcare practitioner before starting any supplement, especially if you take prescription medication or are pregnant or nursing.

Bring the sun indoors.

About $0.73 a day, with free shipping to any US address.

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*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease. Consult your healthcare practitioner before using any supplement.