Medicines & Supplements A to Z > Niacin


Last updated on July 12, 2019.

Overview   |   Dosage   |   Side Effects   |   Where To Buy  

Niacin (Vitamin B3)

GENERIC NAMES: Vitamin B3, Niacin, Nicotinic acid 



What is Niacin for?

Niacin is a water-soluble vitamin that has an important role in metabolism, and functioning of the nervous and digestive system. It can also inhibit the breakdown of fats and hinder the formation of fatty acids and therefore can be used as an add-on therapy for hyperlipidemia (high cholesterol), including both hypercholesterolemia and hypertriglyceridemia. Niacin is used to treat niacin deficiency (pellagra) which may be caused by malnutrition, certain medical conditions and medicines.

How to use it?

Niacin can be taken by mouth as extended-release tablets (Niaspan). Do not crush or chew the tablets. You should start with 500 mg once daily at bedtime and your doctor may increase 500 mg every 4 weeks according to your response. The maintenance dose is 1000-2000 mg once daily with a maximum daily dose of 2000 mg. 

When used as a dietary supplement, usual adult doses of Niacin range from 50 to 100 mg per day.

What are the side effects of Niacin?

Common side effects of Niacin are head and neck flushing, constipation, indigestion, nausea and vomiting.

Where to buy Niacin in Hong Kong?

In Hong Kong, many types of Niacin are over-the-counter medicines and can be purchased without a prescription from any retail outlet in Hong Kong. This includes grocery stores, convenience stores, medicine shops, and pharmacies. They can also be obtained from doctors.

Niaspan is a prescription-only medicine so it requires a prescription from a doctor to be purchased in a pharmacy. 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

For detailed information about the use of Niacin 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.