Medicines & Supplements A to Z > Vitamin D3

Vitamin D3

Last updated on 18/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions  |   Tips  |   Where To Buy  

GENERIC NAME: Colecalciferol / Cholecalciferol / Vitamin D3


BRAND NAME(S) IN HONG KONG: Blackmores Vitamin D3, Vitamin D Jamieson, Doctor’s Choice Vitamin D3 1000 IU 醫之選 維他命 D3 1000 IU

DRUG CLASS: Vitamin (fat soluble); Vitamin D analog

USED FOR: Prevention and treatment of Vitamin D deficiency 

OTHER DRUGS IN THE SAME CLASS: Vitamin A, Vitamin E, Vitamin K

AVAILABLE DOSAGE FORMS: 2000 IU, 5000 IU, 10000 IU (softgels)

Overview of Vitamin D

There are several types of Vitamin D supplements available in Hong Kong, namely ergocalciferol (calciferol, Vitamin D2), colecalciferol (Vitamin D3), dihydrotachysterol, alfacalcidol (1α-hydroxycholecalciferol), and calcitriol (1,25-dihydroxycholecalciferol). 

Vitamin D deficiency is usually observed in people with limited sunlight exposure or with a diet that is deficient in Vitamin D. Vitamin D deficiency can be prevented and reversed by taking oral supplements of ergocalciferol or cholecalciferol on a daily basis for months. 

On the other hand, the combination of colecalciferol with Calcium Carbonate is also available for people who have both calcium and Vitamin D deficiency. 

For people who have severe renal impairment, alfacalcidol or calcitriol can be used. These medicines are activated forms of Vitamin D and do not require further physiological activation (hydroxylation) by the kidney. 

In addition, calcitriol is licensed for the management of postmenopausal osteoporosis whereas paricalcitol, a synthetic Vitamin D analogue, is licensed for the prevention and treatment of secondary hyperparathyroidism associated with chronic kidney disease.

What is Vitamin D3 for?

Vitamin D3 is mainly used for prevention and treatment of Vitamin D deficiency.

How to use it?

Vitamin D3 is available as oral preparations. If you are using it for the prevention of Vitamin D deficiency, you can take 400 units daily. If you are using it for the treatment of Vitamin D deficiency, you can take 800 units daily. For severe deficiency, higher doses may be required.

What are the side effects of Vitamin D3?

Vitamin D3 is generally safe to use. However, abdominal pain, headache, high calcium level in blood or urine, and/or nausea may occasionally occur.

Who should not take Vitamin D3?

Anyone who has an increased calcium level in blood, and metastatic calcification.

Pharmacist Tips:

It is always highly recommended to get nutrients like Vitamin D from natural sources first, such as salmons, foods fortified with Vitamin D, and egg yolks. Vitamin D is also produced by sunlight exposure. 

Pay attention to the amount of Vitamin D in different products as it can vary. Taking too much Vitamin D may lead to Vitamin D toxicity. You may experience symptoms such as nausea, vomiting, and sweating. 

Chew the tablets before swallowing for chewable preparations. 

Common dosing schedule:
Vitamin D3 can be taken with or without meals. 

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Vitamin D3 may interact:
Aluminium hydroxide
– Bile acid sequestrants (e.g. Cholestyramine)
– Thiazide diuretics (e.g. Hydrochlorothiazide

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Vitamin D3 in Hong Kong?

In Hong Kong, Vitamin D3 is an over-the-counter medicine that can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health. 

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at

Need more information?

For detailed information about the use of Vitamin D3 in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.