Does vitamin B repel mosquitoes?
Last updated September 3, 2026.
No - a scoping review of 104 papers found thiamine's support is entirely anecdotal or from uncontrolled trials; controlled experiments on insect landing and feeding found no repellency, and the authors conclude thiamine cannot repel arthropods at any dose. The stakes: trusting a debunked repellent in dengue or malaria country substitutes a placebo for real defense. The same literature's gold standard: topical DEET - safest and most effective across decades of evidence, safe over 2 months of age including pregnancy - with picaridin as the odorless equal. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What to do
- Skip the B1 pills for bites: settled science - no repellency at any dose.
- Use what is registered: DEET or picaridin on exposed skin.
- Treat myths as risk in disease regions: a placebo repellent is worse than none.
- Get seen if: fever follows bites within weeks of travel to mosquito-disease regions - mention the exposure.
Related questions
- Can an online doctor see pictures of my rash?
- What medications make you sun-sensitive?
- Heat rash vs hives?
- How long does a sunburn last?