Vitamin B3
Browse vitamin B3, better known as niacin, in two forms: flush-free nicotinamide and nicotinic acid. You will also find B3 in B-complex formulas. Below we explain which form suits which use, and how to take it.Read more →
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Niacin explained: nicotinamide, nicotinic acid and flush-free forms
Vitamin B3 is better known as niacin. It is water-soluble, so your body keeps only a small reserve and needs a fresh supply each day. Inside your cells, B3 is turned into NAD, a helper molecule that hundreds of enzymes rely on. This is why niacin contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. It also contributes to normal psychological function, the normal function of the nervous system, and the maintenance of normal skin and mucous membranes.
Your body can also make a small amount of niacin from tryptophan, an amino acid in protein-rich food. That route needs riboflavin, or vitamin B2, plus iron. It is one reason B3 is so often sold inside a complex instead of on its own.
Nicotinamide and nicotinic acid behave differently
Nicotinamide, also printed as niacinamide, does not widen blood vessels, so it does not cause flushing. Nicotinic acid does: warm, red, tingling skin on the face, arms and chest, often within half an hour and usually gone within about 30 minutes. That is uncomfortable rather than harmful, but it is the main reason people stop taking B3. Labels rarely spell this out. "Niacin" or "vitamin B3" with no further detail is usually nicotinic acid, and "flush-free" can mean either nicotinamide or inositol hexanicotinate, a slower-releasing form built on inositol.
- Nicotinamide capsules and tablets, flush-free, for steady daily use.
- Nicotinic acid, including timed-release versions that spread the dose.
- B-complex and multivitamin formulas with niacin at everyday amounts, next to the wider B vitamin range.
How we choose the vitamin B3 we stock
We look at three things: the form, the amount per capsule, and the company it keeps. Nicotinamide is our default for daily use, because it delivers B3 without the flush. We also stock nicotinic acid for people who deliberately want that form, and we name it clearly instead of hiding it behind the word "flush-free". Very high single-nutrient doses only make sense with a clear reason, so we keep modest amounts in our complexes too. Every product passes our compliance team, and we spot-check batches ourselves and through independent labs. See how we select brands and products.
Who a separate vitamin B3 actually suits
A shortage of niacin is rare in the UK, because meat, fish, peanuts, wholegrains and fortified cereals all supply it. A standalone B3 is therefore a targeted choice rather than a daily basic. It suits people on a limited or low-protein diet, people cutting back on heavy drinking, and anyone told by a professional to top up. If your aim is broader, our supplements for everyday energy or a B-complex are usually the better starting point.
Be realistic about what to expect. B3 supports processes your body already runs, so it does not create energy out of nothing. If you are correcting a low intake, give it two to three weeks of consistent use before judging the result, and take it with a meal to keep it gentle on the stomach.
Frequently asked questions
Vitamin B3, or niacin, is a water-soluble B vitamin. Your cells convert it into NAD, a coenzyme that hundreds of enzymes need to release energy from food. Because of that role, niacin contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. It also contributes to normal psychological function, the normal function of the nervous system, and the maintenance of normal skin and mucous membranes. Since your body stores little of it, you need a regular supply.
Niacin is spread widely across everyday food. The richest sources are liver, lean beef and pork, poultry, fish, peanuts and wholegrains. Milk, cheese and eggs contribute through their protein, because your body can also make niacin from the amino acid tryptophan. Many UK breakfast cereals are fortified with it as well. This is why a real shortage is uncommon here, and why a supplement is usually about topping up a limited diet rather than filling an obvious gap.
It comes down to whether you want to avoid flushing, and whether you prefer a single nutrient or a complex.
| Form | Causes flushing | Suits |
|---|---|---|
| Nicotinamide (niacinamide) | No | Steady daily use |
| Nicotinic acid | Often | Those who want this specific form |
| Nicotinic acid, timed-release | Less, spread out | Sensitive users of this form |
| Inositol hexanicotinate | No | Flush-free preference |
| B-complex or multivitamin | Rarely, amounts are low | General daily cover |
Read the ingredient panel, not the front label, because "flush-free" is used for more than one form.
Niacin is counted in niacin equivalents (NE), which include what your body makes from tryptophan. European reference intakes are set against energy intake rather than one flat figure. UK guidance also states the supplement levels considered unlikely to cause harm, and these differ sharply between the two forms.
| Reference | Amount |
|---|---|
| EFSA population reference intake, adults | 1.6 mg NE per MJ |
| NHS: nicotinic acid from supplements | 17 mg a day or less |
| NHS: nicotinamide from supplements | 500 mg a day or less |
The flush is a temporary widening of small blood vessels in the skin. You get warmth, redness and tingling across the face, arms and chest, usually starting within 20 to 30 minutes and fading within about half an hour. Only nicotinic acid does this, and it can start at fairly modest amounts. To avoid it altogether, choose nicotinamide. If you are taking nicotinic acid, take it with food and skip alcohol and hot drinks around your dose, since both make flushing stronger.
Take it with a meal. Food does not change how much you absorb, but it makes B3 easier on the stomach and softens flushing if you use nicotinic acid. Because niacin is water-soluble, a consistent daily time works better than a large occasional dose. Many people prefer the evening with a nicotinic acid product, so any flush happens at home rather than at work. If you take a B-complex, morning with breakfast is the simplest habit to keep.
For most people a complex is enough. B vitamins work in the same metabolic pathways, and B3 production from tryptophan even depends on B2 and iron, so covering the group is often more logical than isolating one. A standalone B3 makes sense when you want a specific form, or a higher amount for a specific reason. If you already take Multivitamins, check the label first so you do not stack two sources without meaning to.
Speak to your GP or pharmacist first if you take prescribed medication, or if you have a liver condition, diabetes, gout or low blood pressure, since higher niacin intakes can affect all of these. During pregnancy and breastfeeding, keep to what your midwife or doctor advises rather than adding a high-dose B3. Children normally get all the niacin they need from food. And stay inside the UK supplement guidance: up to 17 mg of nicotinic acid or up to 500 mg of nicotinamide a day.
