Your questions, expert answers

You can take d.velop™ at any time of day. We recommend that you take d.velop™ on a daily basis, alongside food. 

It takes several weeks, rather than months of daily calcifediol intake to reach a new steady state level (this level depends on the daily dose), which will not significantly increase anymore. Even more, this level will decrease to a lower level again if daily supplementation is stopped.

We recommend that you stop taking your traditional vitamin D supplements while taking d.velop™.

We recommend that you consult with your doctor before using or continuing to use d.velop™ and any other dietary supplement if you are nursing, pregnant, trying to conceive, or taking medication. These statements have not been evaluated by the Food and Drug Administration.

In rare cases when taking any supplement, there is the possibility of experiencing some degree of an upset stomach. Please consult your doctor if you experience extended symptoms.

We get a majority of our vitamin D through sunlight. Vitamin D is produced when our skin is exposed to the sun. The sun as a source of vitamin D can be a challenge throughout most of the year based on where we live, as well as during the winter months. When the sun shines, we also protect ourselves with clothes and sunscreen.

In most populations insufficient vitamin D status is a major public health issue; 88% of the people worldwide are insufficient1. About 10% vitamin D comes from the diet, the remaining 90% is obtained from the sun2.

The following groups are at risk of vitamin D insufficiency or deficiency:

  • People who are housebound 
  • Community-dwelling people whom are older, or have disabilities 
  • People in residential care 
  • People with darker skin tones 
  • People who regularly avoid sun exposure or work indoors 
  • People who live in northern latitudes, and during the wintertime. 
  • COVID-19 “stay-at-home” policies are likely to further lower already low vitamin D levels


  1. Hilger J, Friedel A, Herr R, Rausch T, Roos F, Wahl DA, Pierroz DD, Weber P, Hoffmann K. A systematic review of vitamin D status in populations worldwide. Br J Nutr. 2014 Jan 14;111(1):23-45. doi: 10.1017/S0007114513001840. Epub 2013 Aug 9. PMID: 23930771.
  2. Mendes MM, Hart KH, Botelho PB, Lanham-New SA. Vitamin D status in the tropics: Is sunlight exposure the main determinant? Nutrition Bulletin. 2018;43(4):428-434. doi:10.1111/nbu.12349

We think of vitamin D as the “goldilocks” vitamin - “not too high, not too low, we want it to be just right.”


If vitamin D levels are too high you can run into a rare, but potentially serious situation called “vitamin D” toxicity where the buildup of vitamin D levels in the blood may cause nausea, vomiting, weakness or can lead to other problems such as calcium buildup, and kidney issues. 


If vitamin D levels are too low, you may experience symptoms of deficiency such as loss in bone density, weakness or fatigue, and reduced immune function. 

High Levels of vitamin D are likely in the following situations:

  • With over-supplementation or blind-supplementation. Many people may be taking more vitamin D than they need to, which can cause levels to be too high!
  • During the summer, when there is plenty of sun and longer daytime hours where it is light out.
  • We do not recommend continuing d.velop™ if you have measured high levels of vitamin D in your blood.

Low levels of vitamin D are likely reached in the following situations:

  • If you live above 37 degrees North of the equator and/or use necessary sun protection.
  • If you do not take a vitamin D supplement, vitamin D levels are difficult to raise with dietary intake from foods alone. 
  • If you suffer from a malabsorptive disease, or are taking certain medications. 

Yes, d.velop™ is vegetarian, and free of GMOs.

At this time, d.velop™ is not Kosher.

At this time d.velop™ is not Halal.

Yes! Even if you live in sunnier climates and/or take vitamin D, you still might be falling short, there are so many individual factors that can affect your blood level of vitamin D. The only way to truly know if your diet or environment is delivering what you need is to take a test.

The “blood” level of vitamin D that is presented in your test is equal to the concentration of total vitamin D level in plasma or serum. It is measured from a dried blood spot using an LC/MS method, which is a gold standard technique. This method of measuring plasma vitamin D levels from a dried blood spot has been validated against levels in liquid plasma.

At-home testing adheres to high standards. If you have, or are at risk of lower levels of vitamin D it can be a way to see improvements in vitamin D levels over time using supplementation of d.velop™. Especially due to social distancing, in person lab appointments at doctor’s offices can be hard to come by, and are more expensive compared to at home testing options.

Your lab measurements could differ from your current test results for many reasons including the timing and season that you were initially tested, differences in sun exposure, and even changes in dietary intake of vitamin D (food and supplements) between when you were last tested and now. Be sure to follow the instructions on your insert closely so that user error does not play a role in your results.

Vitamin D can be found naturally in oily fish (such as salmon, mackerel, sardines and herring), egg yolks, dairy products, beef liver, and mushrooms. In the United States, some foods are fortified with vitamin D, such as dairy products, orange juice, soy milk and cereals. Fortification means that vitamin D has been added in, since as American’s we rely on these foods or supplements to help us meet our daily needs because there are a limited number of foods that are naturally rich in vitamin D1.


  1. Calvo MS, Whiting SJ, Barton CN. Vitamin D fortification in the United States and Canada: Current status and data needs. Am J Clin Nutr 2004;80:1710S-6S

No, we advise that you do not exceed the recommended two tablet dose of d.velop™ daily. Excess vitamin D may cause side effects such as nausea, stomach discomfort, and even bone, or kidney problems. If you are concerned about your vitamin D intake, we recommend you test your vitamin D levels and speak with your doctor. Our dietitians will also be able to answer your questions about appropriate vitamin D levels.

Clinical studies have shown that ampli-D® can achieve optimal vitamin D status (75nmol or 30ng/mL), on average 3X faster, and is 3X more effective compared to the same mcg dose of traditional vitamin D3.

There are many forms of vitamin D found in foods such as fatty fish, milk, eggs, or mushrooms. Here’s an overview:

  • Calcifediol (25-hydroxyvitamin-D3, ampli-D®): Fatty fish, milk, eggs or supplements with ampli-D®, such as d.velop™
  • Vitamin D2 (Ergocalciferol): Mushrooms, fortified foods or supplements
  • Vitamin D3 (Cholecalciferol, colecalciferol): Sunlight, milk, eggs, fatty fish, fortified foods or supplements

Many people understand their vitamin D supplement dosage in terms of international units (IU). Another way you may see vitamin D listed is in micrograms. For vitamin D3, the conversion factor from micrograms to IU is: 1 microgram of vitamin D3 = 40 IU of vitamin D activity. One tablet of d.velop™ is 10 mcg of calcifediol. It acts 3x faster and more effective in raising vitamin D levels in the blood compared to vitamin D3. There is no official conversion factor for calcifediol from micrograms to IU. However, since we known that calcifediol is 3x faster and more effective than traditional vitamin D in raising blood levels on a microgram per microgram comparison we can understand that: 40 IU x 3 x 10 micrograms (the dose of calcifediol in one tablet of d.velop™ = 1200 IU), therefore 1 tablet of d.velop™ with 10 micrograms of calcifediol would be 1200 IU equivalent.

It’s all about the absorption efficiency here. Everyone differs in how they absorb vitamin D3 and convert it to calcifediol. With traditional vitamin D3 this can take months to reach optimal levels of vitamin D in the body. Calcifediol has superior bioavailability, therefore you are more likely to reach sufficient vitamin D levels in days compared to the months it may take with ordinary vitamin D3 supplementation. 


Let’s talk science:

In a study by Shieh et al1, it was found that a 20 mcg dose of calcifediol took 28 days to reach sufficient levels in the blood, whereas 60mcg dose of vitamin D3 took over 122 days.


  1. Albert Shieh, Christina Ma, Rene F. Chun, Sten Witzel, Brandon Rafison, Hannah T. M. Contreras, Jonas Wittwer-Schegg, Leon Swinkels, Tonnie Huijs, Martin Hewison, John S. Adams, Effects of Cholecalciferol vs Calcifediol on Total and Free 25-Hydroxyvitamin D and Parathyroid Hormone, The Journal of Clinical Endocrinology & Metabolism, Volume 102, Issue 4, 1 April 2017, Pages 1133–1140,