B3 Dosage Guide
Recommended daily intake by age and gender — based on NIH Dietary Reference Intakes.
Our assessment
Based on FDA data, niacin (nicotinic acid) from food is safe, but dietary supplements containing 30 mg or more can cause significant side effects. The most common reaction is a skin flush, but at higher medical doses of 1,000 mg or more per day, more serious risks emerge, including low blood pressure (increasing fall risk), extreme tiredness, and high blood sugar levels FDA FAERS ↗.
Safety profile
FDA data indicates that supplements with 30 mg or more of nicotinic acid can cause the skin on the face, arms, and chest to turn red and burn, tingle, and itch. This can also lead to headaches, rashes, and dizziness FDA FAERS ↗. At doses of 1,000 mg or more per day, more severe side effects include low blood pressure (which can increase the risk of falls), extreme tiredness, and high blood sugar levels FDA FAERS ↗. Report counts for each specific side effect are not available in the provided data.
How it works
Niacin is a B vitamin that helps the body convert food into energy. The provided data does not include specific studies on its mechanism of action. Data not available on specific studies from the provided list.
Our recommendation
Be cautious with niacin supplements containing 30 mg or more, as they can cause uncomfortable flushing and other side effects FDA FAERS ↗. People taking tuberculosis drugs such as isoniazid and pyrazinamide should be aware that these medications interfere with the body’s ability to convert tryptophan to niacin, potentially affecting niacin levels FDA FAERS ↗. Anyone taking niacin at doses of 1,000 mg or more per day should be monitored for low blood pressure, extreme tiredness, and high blood sugar FDA FAERS ↗. Always consult a healthcare provider before starting high-dose niacin.
AI-assisted analysis. Data sourced from NIH ODS.
Understanding RDAs
Dietary Reference Intakes (DRIs) are a set of reference values used to plan and assess nutrient intakes of healthy people. They include:
- RDA (Recommended Dietary Allowance) — The average daily intake sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals.
- AI (Adequate Intake) — Established when evidence is insufficient to develop an RDA. Based on observed nutrient intake by healthy people.
- UL (Tolerable Upper Intake Level) — The maximum daily intake unlikely to cause adverse health effects. Exceeding the UL increases the risk of toxicity.
Values vary by age, gender, and life stage (pregnancy, lactation).
Source: National Academies of Sciences, Engineering, and Medicine
Recommended Dietary Allowance
| Life Stage | Recommended Amount |
|---|---|
| Birth to 6 months | 2 mg |
| Infants 7–12 months | 4 mg NE |
| Children 1–3 years | 6 mg NE |
| Children 4–8 years | 8 mg NE |
| Children 9–13 years | 12 mg NE |
| Teen boys 14–18 years | 16 mg NE |
| Teen girls 14–18 years | 14 mg NE |
| Adult men 19+ years | 16 mg NE |
| Adult women 19+ years | 14 mg NE |
| Pregnant teens and women | 18 mg NE |
| Breastfeeding teens and women | 17 mg NE |
Source: National Academies of Sciences, Engineering, and Medicine