New study reveals that high-dose niacin therapy can be hazardous.
Written by Susan Parker | Updated on May 28, 2025
Reviewed by Susan Parker
11 sources cited
For many years, niacin has been promoted as a way to protect the heart, with high doses prescribed to increase HDL cholesterol and prevent heart disease. However, recent research challenges this belief, suggesting that large doses of niacin may actually be harmful, leading to severe side effects and an elevated risk of mortality. Keep reading to discover the truth about the misconceptions surrounding this vitamin and find out what truly benefits heart health.
Overview
The HDL myth
Mainstream medical professionals have advocated for high doses of niacin due to its impact on HDL (good) cholesterol. These doses are in grams rather than milligrams.
While studies have shown that individuals with higher HDL levels generally have a lower risk of heart disease, the correlation between increased HDL through niacin and improved heart health is not as straightforward as once believed.
Research indicates that solely raising HDL levels, without addressing other physiological factors, does not effectively protect the heart and arteries.
Insights on niacin from research
Initial experiments in the 1970s initially suggested that large niacin doses were beneficial for middle-aged men at risk of heart issues. However, subsequent studies revealed that the reduced mortality rate observed in previous niacin users was not directly linked to niacin consumption.
A more extensive four-year study involving over 25,000 individuals aged 50 to 80 found that while megadoses of niacin did elevate HDL and lower LDL (bad cholesterol) and triglycerides, these effects did not prevent heart attacks or enhance heart disease survival rates.
In fact, the research showed that high niacin doses increased the likelihood of premature death, a concerning and unexpected outcome.
"For every 200 people treated with niacin, there might be an additional death," warned Donald Lloyd-Jones, the chair of the preventive medicine department at Northwestern University Feinberg School of Medicine and Northwestern Memorial Hospital. "With such findings, this therapy is deemed unsuitable for the majority of patients."
Side effects
The side effects of excessive niacin consumption may include:
- Flushing and itching
- Nausea and vomiting
- Liver damage, jaundice, and hepatitis
- Increased diabetes risk and blood sugar issues
- Gout
- Blurred vision and eye complications
Beneficial aspects of niacin
Despite the risks associated with high doses, niacin in appropriate amounts remains a vital vitamin. Niacin is necessary for the production of crucial enzymes, particularly those involved in energy production. Enzymes for fat, carbohydrate, alcohol, and protein breakdown rely on niacin.
Men should aim for 16 mg of niacin daily, while women should target 14 mg, with pregnant women needing 18 mg. However, adhering strictly to the recommended daily allowance may merely sustain basic functions.
Most B-complex supplements provide 100 mg of niacin, a generally safe dosage. It is advised to avoid time-release niacin supplements.
If you prefer obtaining niacin from food sources, consider tuna, salmon, poultry, beef, peanuts, and fortified foods. Coffee and tea also contain small amounts.
If your physician suggests a daily niacin megadose for heart health, inform them that this approach is outdated and now considered a hazardous therapy.
Summary
Niacin, a critical nutrient known for its role in elevating "good" HDL cholesterol, has historically been prescribed in large doses to prevent heart disease. However, recent findings indicate that while niacin can raise HDL levels, it does not substantially lower the risk of heart attacks or enhance heart health. Instead, high niacin doses are linked to severe side effects, such as liver damage, increased diabetes risk, and a higher mortality rate, rendering such treatment unsafe for most patients.
