If you’re experiencing itchy, hot skin after taking niacin (vitamin B3)

 If you’re experiencing itchy, hot skin after taking niacin (vitamin B3), you’re likely having what's called a niacin flush — a very common, usually harmless side effect. Here's what’s going on and what you can do:

🔥 What Is a Niacin Flush?

A niacin flush happens when blood vessels dilate (vasodilation), increasing blood flow to the skin.

This leads to:

Warmth or burning sensation

Itchy, red skin, often on the face, neck, and upper chest

Tingling or prickling

It typically starts 15–30 minutes after taking niacin and may last up to 1 hour.

⚠️ Is It Dangerous?

Usually not — it’s a benign effect.

But if it’s very intense, long-lasting, or accompanied by other symptoms (e.g., dizziness, shortness of breath, hives), it could signal a more serious reaction (though rare).

Flush-free niacin (inositol hexanicotinate) doesn’t cause flushing, but it may not be as effective for lipid management.

🧠 Why Does It Happen?

Niacin causes the release of prostaglandin D2, which leads to blood vessel dilation.

This is dose-dependent — higher doses (especially ≥50 mg) are more likely to cause flushing.

✅ Ways to Reduce or Prevent the Flush

1. Take with food — slows absorption.

2. Start low, go slow — begin with a small dose (e.g., 50–100 mg) and build up.

3. Take aspirin (81–325 mg) 30 minutes before niacin — blocks prostaglandins (consult a doctor first).

4. Use extended-release niacin — may reduce flushing, but monitor for liver effects.

5. Stay hydrated — may blunt the intensity.

🚨 When to Seek Help

Contact a healthcare provider if:

The flushing is severe or lasts more than a few hours

You get hives, swelling, or shortness of breath

You experience dizziness or fainting