Reminder: millions of people live and travel in the Caribbean every year without incident. Well-informed and well-equipped, you will enjoy your stay with complete peace of mind.
# Mosquito Repellents: Natural vs Chemical — The Complete Comparison for the Caribbean
Introduction
Facing Caribbean mosquitoes — Aedes aegypti, the vector of dengue, Zika and chikungunya — choosing the right repellent is a public health decision. The market offers two main families: synthetic chemical repellents (DEET, icaridin, IR3535) and natural repellents (neem oil, citronella, lemon eucalyptus). But which one should you choose for a stay in Martinique, Guadeloupe or French Guiana? Here is the complete scientific comparison.
---
Chemical Repellents: Proven Efficacy
DEET (N,N-diethyl-meta-toluamide)
DEET has been the world reference since 1946. Used at concentrations of 20% to 50%, it provides 4 to 8 hours of protection against tropical mosquitoes. The WHO recommends it in dengue-endemic areas. Its mechanism of action involves blocking the olfactory receptors of mosquitoes sensitive to CO2 and lactic acid.
Strengths: maximum efficacy, long duration, broad spectrum (mosquitoes, ticks, sandflies).
Weaknesses: strong odour, can damage certain plastics and synthetic fabrics, not recommended for children under 2 years.
Icaridin (picaridin)
Icaridin is considered the modern alternative to DEET. At 20%, it offers equivalent protection (6 to 8 hours) with better skin tolerance, no strong odour and no effect on plastics. The WHO also recommends it in tropical areas.
Strengths: as effective as DEET, odourless, non-greasy, compatible with plastics.
Weaknesses: slightly less available in pharmacies in the Caribbean.
IR3535 (ethyl butylacetylaminopropionate)
IR3535 is the reference molecule in Europe, notably in Moustidose and Cinq sur Cinq products. At 20%, it provides 4 to 6 hours of protection. It is recommended by the French HCSP for pregnant women and children from 6 months.
Strengths: very good tolerance, recommended for pregnant women and infants, widely available in French pharmacies.
Weaknesses: slightly shorter protection duration than DEET and icaridin.
---
Natural Repellents: Variable Efficacy
Neem oil (Azadirachta indica)
Neem oil contains azadirachtin, a compound that disrupts the reproductive cycle of insects. Studies show repellent efficacy of 70 to 90% for 2 to 3 hours at concentrations of 2%. It is particularly popular in French Guiana and the English-speaking Caribbean islands.
Strengths: natural, biodegradable, effective against Aedes aegypti.
Weaknesses: strong odour (garlic/sulphur), short duration, variable efficacy depending on formulation.
Citronella essential oil (Cymbopogon nardus)
Citronella is the best-known natural repellent. Its actual efficacy is 30 to 60 minutes depending on the formulation. Citronella candles and diffusers have very limited efficacy outdoors. Pure essential oil applied to the skin (diluted in a carrier oil) is more effective but requires frequent reapplication.
Strengths: natural, pleasant indoors, no toxic risk.
Weaknesses: very short duration, insufficient efficacy in high-risk areas.
Lemon eucalyptus (PMD — para-menthane-3,8-diol)
PMD extracted from lemon eucalyptus (Corymbia citriodora) is the only natural repellent recommended by the US CDC as an alternative to DEET. At 30%, it provides 3 to 4 hours of protection. It is not recommended for children under 3 years.
Strengths: proven efficacy, natural, recommended by the CDC.
Weaknesses: not recommended for young children, less available in France.
---
Complete Comparison Table
| Repellent | Recommended Concentration | Protection Duration | Aedes Efficacy | Pregnant Women | Children | Caribbean Availability |
|---|---|---|---|---|---|---|
| DEET | 20–50% | 4–8 h | ★★★★★ | Not recommended | > 2 years | ★★★★ |
| Icaridin | 20% | 6–8 h | ★★★★★ | Possible (medical advice) | > 2 years | ★★★ |
| IR3535 | 20% | 4–6 h | ★★★★ | Recommended | > 6 months | ★★★★★ |
| PMD (eucalyptus) | 30% | 3–4 h | ★★★★ | Not recommended | > 3 years | ★★ |
| Neem oil | 2% | 2–3 h | ★★★ | Possible | All ages | ★★★ |
| Citronella EO | 10–15% | 30–60 min | ★★ | Possible | > 6 years | ★★★★★ |
---
Recommendations by Traveller Profile
Healthy adult: DEET 30% or icaridin 20% — maximum protection, ideal for forest hikes or high mosquito density areas.
Pregnant woman: IR3535 20% as a priority — recommended by the HCSP, good tolerance, sufficient efficacy for tourist stays.
Child 6 months to 2 years: IR3535 only — apply to clothing and avoid hands, face and broken skin areas.
Child 2 to 12 years: IR3535 or low-concentration icaridin (10%) — avoid strong DEET.
"Natural" traveller: PMD 30% (lemon eucalyptus) — the only natural repellent with proven efficacy comparable to synthetic molecules.
French Guiana stay (malaria zone): DEET 50% or icaridin 20% — maximum protection is essential, natural repellents are insufficient.
---
How to Apply Repellent Correctly
- 1Apply after sunscreen (not before), waiting 20 minutes.
- 2Never apply to broken skin, eyes, lips or inside nostrils.
- 3Wash hands after application.
- 4Renew application according to the indicated duration, more frequently with intense sweating.
- 5Combine skin repellent with permethrin-treated long clothing for optimal protection.
---
Conclusion
There is no universal "perfect" repellent — the best choice depends on the traveller's profile, destination and risk level. For the Caribbean in general, icaridin 20% or DEET 30% offer the best efficacy/tolerance ratio for adults. For families with children or pregnant women, IR3535 20% remains the French reference recommended by health authorities.
Natural repellents can complement protection indoors or in low-risk areas, but should not replace synthetic molecules in dengue or malaria endemic areas.