Cholecalciferol: Everything to know about Vitamin D3

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Cholecalciferol, known as Vitamin D3 helps in more ways than one. Whether it is absorbed through sunlight or supplements, it is a vitamin that is crucial to human life.

What is Cholecalciferol?

Cholecalciferol is a form of Vitamin D, more specifically Vitamin D3, and is synthesized by the skin upon exposure of a type of cholesterol known as 7-dehydrocholesterol to ultraviolet B radiation (UVB rays) from the sun. Even though it can be made by our skin, deficiency of this important vitamin is still extremely common, especially in temperate to colder climates which may not have exposure to year-round glorious sunshine.

If you think that you are likely to be deficient in this vitamin, there are supplemental forms available for consumption that can help you to meet your daily requirements.

How Cholecalciferol Works

When cholecalciferol is consumed (Vitamin D3) or synthesized by our skin, it needs to travel to our liver and then to the kidneys for conversion into its active form, Calcitriol. Only then can Vitamin D actually begin to elicit biological effects.

This active form of cholecalciferol then binds to vitamin D receptors where it can then influence gene expression, in this case working primarily to increase production of carrier proteins that improve absorption of calcium in the intestine. Vitamin D receptors are found throughout the body, which indicates the importance of the vitamin in a number of processes and biochemical reactions.

Popular Cholecalciferol Generics And Brands

Oral vitamin D3 is easy to obtain, being available in a wide range of both branded and generic preparations. The standard daily dosage guidelines for most adults stands between 400-800 IU(International Units), even though experts believe that higher doses than this should be consumed. Regardless, assorted strengths are available in many brands. This most common include:

  • Calciferol
  • Drisdol
  • Carlson D
  • Ddrops
  • Decara
  • Enfamil D-Vi-Sol
  • Replesta
  • Thera-D 2000
  • Maximum D3
  • Thera-D Sport, D3 1000
  • Celebrate Vitamin D3 Quick-Melt
  • UpSpringbaby D
  • Super-Strength D-5000
  • Adferol
  • Biocitral-D
  • Xposun

Uses of Cholecalciferol

These are some of the uses of Cholecalciferol:

Cholecalciferol Boosts Calcium Production

One of the primary functions of cholecalciferol in the body, once it is converted into its active form, is to promote the absorption of calcium by the intestines. Sometimes, this absorption can be enhanced 200 to 400 percent given that dietary consumption of calcium is sufficient.

Vitamin D3 Helps With Bone Loss Or Osteoporosis

Osteoporosis and bone loss are common problems afflicting women as they approach and pass through menopause, as the protective effect of estrogen on bones is lost. Estrogen inhibits the resorption of bone in an attempt to supply calcium to meet requirements of other cells in the body.

Deficiency of Vitamin D3 causes increased secretion of parathyroid hormone (PTH), which acts to regulate calcium levels in the blood. If it detects that calcium levels are below normal, it resorts to removing it from bone, leading to bone loss. Osteoporosis is compounded by the loss of calcium from bone and results in the development of a fragile bone matrix. Vitamin D3 administered in conjunction with calcium is an excellent insurance policy against bone loss and osteoporosis.

Cholecalciferol Helps With Kidney Diseases

The kidneys play a very important part in converting cholecalciferol into its active form, following pre-conversion by the liver. Once activated, this hormone then helps to ensure calcium and phosphorus equilibrium is maintained, promoting absorption from the diet. A large aspect of this regulation is maintaining normal parathyroid hormone response, as an over secretion can spell disaster for your bones. If the kidneys become subject to disease or chronic failure, it loses the ability to convert cholecalciferol into its active form, leading to impaired calcium and phosphate metabolism.

As this occurs, PTH becomes elevated after wrongly detecting calcium levels to be too low. Subsequently, PTH tries to overcompensate by leaching calcium out of bone. As a result, a condition known as secondary hyperparathyroidism occurs, which may cause bone pain and a greater likelihood of experiencing fractures.

Persons suffering from chronic kidney disease are at increased risk of developing secondary PTH and require constant monitoring of their levels. While some amount of cholecalciferol is still converted at sites other than the kidney and mildly helps to control PTH secretion, it is often not enough by itself.

Overall, it seems that administration of cholecalciferol helps with managing other disorders that may be brought on by kidney disease, including those of the heart, and even diabetes.

An even better option:

Use a modified cholecalciferol metabolite known as Alfacalcidol, which does not depend on the kidney for conversion into the active form of the vitamin.

Managing Vitamin D Deficiency

Often times, given that you are in good health, daily sun exposure is enough to correct a vitamin D deficiency, with 15 minutes spent in the sun sufficient to synthesize your daily requirements of this vitamin. However, if this is not possible for one reason or another, it then becomes important for you to consume a supplemental form of D3. It must be D3 and not D2, as D2 is inferior to cholecalciferol, and may not address the deficiency appropriately.

Effective management techniques include:

  • For persons up to the age of 18 years who are vitamin D deficient, a daily dose of 2000 IU per day given for a minimum of six weeks is usually enough to achieve an optimal concentration of this vitamin in blood. Following this initial six week period of time, a maintenance dose of 600 to 1000 IU given daily is enough to help maintain health.
  • Adults older than the age of 18 are advised to follow guidelines of 50,000 IU given once per week for a period of eight weeks, or as an alternative 6000 IU daily until blood concentration of over 30mg/mL is achieved. Following that, maintenance therapy of between 1500 to 2000 IU daily is advised.
  • For persons suffering from chronic kidney disease, an activated or pre-activated form of vitamin D is needed such as calcitriol or Alfacalcidol. Alfacalcidol is unique in the sense that it can be converted to active Calcitriol in the liver, as opposed to the ailing kidney.

How Can You Tell If You Have Vitamin D Deficiency?

Many of the signs and symptoms associated with vitamin D deficiency may first be apparent thanks to its manifestations on bones. While initially, it may be asymptomatic, a Vitamin D deficiency may become cumulative making signs visible. They commonly include:


While most common in postmenopausal women, anyone can develop osteoporosis, especially if suffering from chronic kidney disease. Osteoporosis is a condition usually accompanied by low bone mineral density, which compromises the structural integrity of bone, leaving it more prone to breaks and fractures.


Rickets is a common childhood disease that tends to afflict young children in underdeveloped countries. The long bones, such as those of the leg are most visibly affected, appearing deformed or bowed upon visual inspection. In addition to this, growth is generally impeded and is usually accompanied by the development of very soft bones.

Muscle weakness

While symptoms of vitamin D deficiency may be most apparent on the bones, its effects are widespread and will soon manifest anywhere calcium is important. Muscles, for example, need sufficient calcium ions to facilitate normal contraction and function. Deficiency of this important mineral can lead to twitching, loss of muscular control, and associated muscle pain and weakness.


This is an inflammatory disease affecting the bones and tissue in the mouth and around the jaw which inevitably results in the loss of bone and teeth. Commonly associated with Vitamin D deficiency.


Vitamin D also plays an important role in the health of your brain, being involved in the secretion of important neurotransmitters that regulate mood and well-being. Neurotransmitters such as dopamine and serotonin are most notably depleted following vitamin D deficiency and can result in depressive symptoms, loss of motivation and inability to feel pleasure.

Ever wonder why persons living in colder climates are more prone to depression:

The reason is decreased vitamin D synthesis by the skin. This syndrome, known as seasonal affective disorder (SAD), is usually remedied with vitamin D supplementation or exposure to synthetic UV light.

Preeclampsia in pregnant women

Preeclampsia is a serious disease that affects pregnant women which increases their risk of hypertension, complicating the pregnancy. It shares a strong link to low calcium levels, which may be due in no small part to low blood vitamin D levels. Low levels of maternal vitamin D can also impair the development of bones in the fetus, and increase the risk of birth defects.

Cholecalciferol Side Effects

Dietary supplement and other sources of vitamin D cholecalciferol might have the following side effects.

Cholecalciferol May Hinder Growth In Infants

Contrary to popular belief, there is such a thing too much vitamin D cholecalciferol. This is especially true in infants, who need this critical vitamin, but at doses recommended by a pediatrician. Consumption of large amounts of vitamin D enhanced foods causes a scenario of excessive calcium in the blood, known as hypercalcemia.

Vitamin D can be converted into more than one metabolite once in the body, and in cases of excess, the unwanted metabolites bind to the vitamin D receptor stronger than the needed substrate, and subsequently prevent it from interacting and signaling for the intestines to absorb calcium.
The end result is weakened bones, as calcium is not able to make its way into the bone matrix.

Weight Loss

While vitamin D is associated with weight loss, in excess this weight loss can quickly become undesirable. Though it is not fully certain why this excessive weight loss can occur, a few theories put forward indicates the possibility of fat cell suppression, which inhibits the amount of fat any particular cell can hold. In addition to this, increased serotonin levels are associated with reduced propensity to eat under emotional triggers, which can prevent weight gain due to cravings and late night binge-eating.


The occurrence of constipation following cholecalciferol consumption depends heavily on the dose used daily. In general, vitamin D by itself is not responsible for constipation, but rather it is calcium that does this. It is important to keep in mind, however, that vitamin D consumption plays a very key role in the development of hypercalcemia. This is why it is a good idea to consume only as much as you need, or as prescribed by your physician.

Reviews: 10 Things Customers Are Saying About Cholecalciferol

There is a wide range of opinions when it comes to cholecalciferol, but overall the supplement is highly rated, and in most instances is said to do what it claims.

While there are negative reviews, in many instances it seems related to the physical properties of the supplement, which commonly manufactured in a soft gel, is prone to melting at high room temperatures or made from material not vegan-friendly. Apart from that, some negative reviews bear no merit, as customers state it works well but likely mistakenly left an unfavorable review.

Cholecalciferol review

Claims bloodwork reflects the efficacy of the product.

Cholecalciferol review

Safe even when consuming high dose 5000 IU daily; albeit with doctor’s supervision.

Cholecalciferol review

The review is based on physical properties and not supplement itself.

Cholecalciferol review

Merely unsuitable to that individual’s lifestyle.

Cholecalciferol review

Proper Cholecalciferol Dosage

The exact dosage of cholecalciferol you need depends on several factors. For instance, age, body weight, current nutritional status and overall climate all play roles in determining how much you may need. If you live in a tropical region with generous sunshine, you are unlikely to need any supplemental form of vitamin D, as your skin is able to synthesize enough for the day from as little as 15 minutes exposure to the sun.

However, if you live in colder climates that are further from the equator, you may find yourself needing supplemental support far more often. Given that deficiency has not set in, a dose of 1000 to 2000 IU daily is usually sufficient to meet the body’s goals for the day. If however, you may already be deficient in this vitamin, dosage guidelines are much greater as briefly outlined above. Regardless, the most important thing you can do is to follow your doctor’s recommendations and do not self-diagnose.
This is the actual recommended daily intake:

  • Infants – 400 IU
  • Children and adults (less than 70 years old) – 600 IU
  • Adults older than 70 – 800 IU

Should You Take Cholecalciferol?

Whether or not you should take cholecalciferol is not a decision you should make independently, even though it is commonly sold over-the-counter at numerous drugstores and even supermarkets around the world.

What is clear, however, is the fact that everyone needs this vitamin for optimal function and normal metabolic processes. Sun exposure is sufficient for the majority of people, but there are circumstances which mandate you consult your physician to determine if you need a supplemental form of it.

How To Buy Cholecalciferol

Most varieties of cholecalciferol do not require a prescription, and can easily be purchased over-the-counter at your local pharmacy, or online and delivered to you by mail. While the injectable versions and high potency oral preparations may require a prescription, the circumstances are rare and are usually determined by your physician.

Final Thoughts

Regardless of if you decide to take supplemental cholecalciferol or not, the best course of action is to have your values checked via blood testing. These results can then be discussed with your doctor, helping you create a way forward. With that in mind, cholecalciferol is generally a very well tolerated supplement, and a critical part of maintaining good health.