Can vitamins, specifically vitamin B1 (thiamine), decrease attractiveness to mosquitoes?

Vitamin B1 (Thiamine) Does Not Decrease Attractiveness to Mosquitoes

There is no scientific evidence supporting the use of vitamin B1 (thiamine) as an effective mosquito repellent, whether taken orally or applied topically. 1 The most recent and comprehensive research clearly demonstrates that thiamine cannot repel arthropods in any dosage or route of administration.

Scientific Evidence Against Vitamin B1 as a Mosquito Repellent

• A 2022 scoping review of 104 relevant studies found that reports of thiamine's repellency are primarily anecdotal and based on uncontrolled trials 1
• Controlled experiments on insect landing and feeding found no evidence of repellency from vitamin B1 1
• A 2005 study using human subjects and Anopheles stephensi mosquitoes found no effect of vitamin B supplementation on mosquito attraction 2
• No insect bite prevention guidelines after the 1990s claim thiamine is an effective repellent 1

Conflicting Evidence

While most evidence refutes thiamine's effectiveness, there is one limited pilot study from 2020 suggesting topical (not oral) application of thiamine hydrochloride might have some repellent effect when applied directly to skin 3. However, this contradicts the larger body of evidence and has not been replicated in more robust studies.

Effective Mosquito Prevention Strategies

Instead of relying on unproven remedies like vitamin B1, the CDC and other authoritative guidelines recommend:

1. Use EPA-registered repellents containing DEET (concentration <50%) applied to exposed skin 4
2. Wear protective clothing - long-sleeved shirts and long pants when outdoors, especially during dusk to dawn 4
3. Use permethrin-treated clothing for additional protection 4
4. Avoid outdoor activities during peak mosquito feeding times (dusk to dawn) 4
5. Use physical barriers such as screened windows, doors, air conditioning, and bed nets 4

Common Pitfalls and Misconceptions

• Many people continue to believe in vitamin B1's effectiveness despite scientific evidence to the contrary 1
• Relying on ineffective repellents like vitamin B1 puts individuals at risk of mosquito bites and potential disease transmission 1
• The continued promotion of debunked repellents on the commercial market poses a serious risk in areas with endemic mosquito-borne diseases 1

Promising Alternative Repellents

Research has identified several potentially effective natural repellent compounds:

• Lactones (δ-decalactone and δ-undecalactone) have shown promising repellent properties against both Anopheles gambiae and Aedes aegypti mosquitoes 5
• Other compounds with potential repellent activity include 2-nonanone, 6-methyl-5-hepten-2-one, and linalool 5

For effective protection against mosquito bites and associated diseases, individuals should rely on evidence-based prevention strategies rather than unproven remedies like vitamin B1.