NutriStack
Simvastatin and Vitamin B3, a caution.
The combination of high-dose niacin with simvastatin carries an elevated risk of myopathy and rhabdomyolysis. Simvastatin already has a higher baseline myopathy risk than some other statins, making this combination of particular concern at higher doses.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Simvastatin and Vitamin B3
- Pair type
- Caution
- Evidence (highest tier)
- Strong
- Source citations
- 1 source
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Caution · Strong evidence
Caution
What is happening. The combination of high-dose niacin with simvastatin carries an elevated risk of myopathy and rhabdomyolysis. Simvastatin already has a higher baseline myopathy risk than some other statins, making this combination of particular concern at higher doses.
Mechanism. Both simvastatin and high-dose niacin independently increase myopathy risk. Simvastatin's CYP3A4 metabolism creates additional vulnerability. Combined myotoxic effects impair skeletal muscle mitochondrial function, increasing the risk of clinically significant rhabdomyolysis.
Recommendation. Avoid high-dose niacin (>500mg/day) with simvastatin. The FDA recommends limiting simvastatin dose to 20mg/day when combined with niacin >1g/day. Report any muscle symptoms immediately.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Simvastatin and Vitamin B3 are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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