Flushing Niacin

To catch up on the current Long Covid research I am going to tackle Niacin and the NAD + deficiency theory. Today we will start with the supplement Niacin.

Vitamin B3 is one of eight B vitamins. It is also referred to as niacin/ nicotinic acid/nicotinamide.

B vitamins help the body convert carbohydrates into glucose which the body uses to produce energy. They also help the body use fats and protein and are needed for a healthy liver, healthy skin, hair, eyes and nervous system.

Niacin also helps the body make various sex and stress-related hormones in the adrenal glands and other parts of the body. Niacin helps improve circulation, and it has been shown to suppress inflammation.

All the B vitamins are water-soluble, meaning that the body does not store them so you need to get your body's requirements for B3 through your diet. It is rare to have a B3 deficiency. In the UK/USA a deficiency is usually due to alcoholism and symptoms include:

  • Indigestion

  • Fatigue

  • Mouth ulcers

  • Vomiting

  • Poor circulation

  • Depression

A severe deficiency can cause a condition known as Pellagra - cracked, scaly skin, burning mouth, swollen bright red tongue, dementia, and diarrhoea.

Dietary sources of B3:

  • Beetroots

  • Brewer's yeast

  • Beef liver

  • Beef kidney

  • Salmon, Swordfish,Tuna

  • Sunflower seeds

  • Peanuts

  • Fortified breads and cereals


Recommended daily amounts (RDA) are low. For men, 19 years and older: 16 mg. For women, 19 years and older: 14 mg.

Recommended dose for Long Covid by Dr Ade Wentzel is 100 mg a day of the flushing variety -Please see safety below


At high doses niacin can be toxic. Side effects can be unpleasant and even dangerous. High doses ( 50mg +) of niacin can cause:

  • Niacin Flush - burning, tingling sensation of face and chest with red/flushed skin

  • Stomach discomfort, bloating, diarrhoea

  • Headache

  • Dizziness

  • Blurred vision

  • An increased risk of liver damage

You should not take niacin at high doses without your doctor's supervision. You will need your liver function monitored via a blood test.

Taking an aspirin 30 minutes prior to the niacin may help reduce the niacin flush

People with a history of liver disease, kidney disease, gout or stomach ulcers, should not take niacin supplements. Those with diabetes, gallbladder disease, coronary artery disease and unstable angina should do so only under the close supervision of their doctors. Taking niacin for a long period of time can result in an imbalance of other important B vitamins. For this reason, you may want to take a B-complex vitamin, which includes all the B vitamins.

** Niacin may worsen Mast Cell Activation Syndrome by increasing histamine**

Possible Interactions:

Because of its impact on the liver, niacin can interact with several medications. If you are currently taking medications, or regularly drink alcohol, you should not use niacin without talking to your GP first. Below is a list of some medications that may interact with vitamin B3.

Antibiotics, tetracycline


Anti-epileptic medications


Blood pressure medications

Cholesterol-lowering medications: bile-acid sequestrants


Diabetes medications: Niacin may increase blood sugar levels

Nicotine patches


  • Atherosclerosis and heart disease - niacin slows down the progression of atherosclerosis, risk of heart attacks and death in those with existing heart disease

  • Osteoarthritis - a study suggests it can improve arthritis symptoms, including increasing joint mobility and reducing the amount of non-steroidal anti-inflammatory drugs (NSAIDs) needed.

  • Alzheimer disease: Population studies show that people who get higher levels of niacin in their diet have a lower risk of Alzheimer disease.

  • Cataracts: One large population study found that people who got a lot of niacin in their diets had a lower risk of developing cataracts.

  • Long Covid (LC): Several research papers have been recently published about the NAD+ deficiency theory and how this leads to Long Covid. NAD+ can be replaced by taking Niacin supplementation. It is proposed that those with LC fatigue may recover as quickly as 2 weeks after taking niacin. Those with heart involvement may take 3-6 months and those with dysautonomia/ POTS longer 12 months +. But as you can see from the above info the amount needed to be taken (100 mg) may be associated with unpleasant side effects, and many already on medications won't be able to taken niacin, and it could potentially worsen Mast Cell Activation Syndrome by raising histamine levels. Lots to consider before taking...

Look out for my future post NAD+ Defiency Theory to understand the role of Niacin in LC further

100 views0 comments

Recent Posts

See All