# Homemade Repellents That Actually Work
Summer brings long evenings on the terrace, trips into nature, and picnic blankets spread out in the park. Along with that, however, come unpleasant companions – mosquitoes and ticks. While chemical repellents from the drugstore promise instant protection, more and more people are looking for natural alternatives. The internet is full of recipes for homemade mosquito and tick repellents, but what actually works and what is merely a myth spreading across social media faster than mosquitoes themselves on a summer evening?
The answer isn't black and white. Some natural substances have a proven repellent effect, while others work more as a placebo or have such a short-lived effect that they have little practical value. Let's take an honest look at the whole issue – backed by scientific findings, but also with good old common sense.
Why mosquitoes and ticks seek us out in the first place
Before we dive into evaluating individual repellents, it's worth understanding what actually attracts insects and parasites to humans. Female mosquitoes – because only females feed on blood – orient themselves primarily by carbon dioxide that we exhale, by body heat, and by the mixture of substances in our sweat. Research published in the journal Cell in 2022 confirmed that mosquitoes are particularly attracted to carboxylic acids on the skin, which explains why mosquitoes absolutely love some people while barely noticing others.
Ticks work a bit differently. They wait in grass or on low shrubs and respond to heat, vibrations, and again to carbon dioxide. The so-called Haller's organ on their front legs can detect the presence of a host from a distance of several meters. This is important to know because an effective repellent must mask or disrupt precisely these chemical signals – and that's a fairly high bar for natural substances.
This is where the first important distinction begins. There is a fundamental difference between a substance that mosquitoes "don't like" in a laboratory petri dish and one that actually protects you during a two-hour walk through the forest. Many natural repellents fail precisely at this transition from the lab to real life.
What actually works – and how well
Among natural substances with the best-documented repellent effect is undoubtedly citriodiol (PMD, p-menthane-3,8-diol), which is derived from the essential oil of lemon eucalyptus (Corymbia citriodora). The US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) list it among recommended active ingredients in repellents. At a concentration of around 30%, it provides protection comparable to lower concentrations of DEET, roughly two to three hours. This is a remarkable result for a naturally derived substance and is definitely worth the attention of anyone wanting to reduce synthetic chemicals on their skin.
Another natural helper that deserves recognition is geraniol – a compound found in a range of essential oils, primarily citronella and geranium. Studies published in the Journal of the American Mosquito Control Association have shown that geraniol has a measurable repellent effect, though shorter-lasting than citriodiol. In practice, this means a geraniol-based repellent needs to be applied more frequently, ideally every 30 to 60 minutes.
And then there's citronella oil, which is probably the best-known "natural repellent" of all. Its reputation is partly deserved – citronella does indeed repel mosquitoes. The problem is that its effect is very short-lived. Most studies show protection in the range of 20 to 30 minutes, after which the oil needs to be reapplied. Citronella candles, so popular on summer terraces, have only minimal practical effect according to a Cochrane systematic review, because the concentration of the active substance in the surrounding air is too low.
Neem oil is also worth mentioning, a traditional remedy used in Indian medicine for centuries. Research confirms its repellent properties, especially against certain species of malaria-carrying mosquitoes. However, its strong smell and relatively short duration of effectiveness make it more of a supplementary measure than a reliable primary protection.
The practical experience of one family from the Vysočina region, who decided to test various natural repellents throughout the summer during regular walks with their dog, nicely illustrates the reality. A mixture of citriodiol with coconut oil worked, in their words, "surprisingly well" against mosquitoes during evening barbecues, but on a full-day trip to the forest where ticks were a threat, they ultimately returned to a product containing icaridin. As the mother of the family noted: "For the garden, a natural repellent is enough, but I wouldn't go into the forest to pick blueberries without a proper product."
This experience actually neatly sums up what science says too. Natural repellents have their place, but the situation needs to be realistically assessed. An evening on a terrace in an urban area is something quite different from a week-long trek through the Šumava mountains. The risk you're taking should match the strength of protection you choose.
Speaking of ticks specifically, one needs to be even more cautious. Ticks are generally more resistant to natural repellents than mosquitoes. While citronella or geraniol can serve as reasonable short-term protection against mosquitoes, the situation with ticks is more complicated. The most effective substance against ticks remains permethrin, which, however, is not applied to the skin but rather to clothing. Among natural alternatives, citriodiol again shows the best results against ticks, but even it falls short of synthetic products.
When we look at what doesn't work or works significantly worse than commonly claimed, we encounter a whole range of popular "guaranteed recipes." Lavender oil smells lovely and has numerous beneficial properties for the skin, but as a mosquito repellent, its effect is minimal and very short-lived. Peppermint is in a similar position – its fresh scent is pleasant to people, but it deters mosquitoes for only a few minutes, if at all.
A special category is vitamin B1 (thiamine), about which a persistent myth circulates that taking it changes body odor and repels mosquitoes. This myth has been repeatedly debunked, including by a study published in the Journal of the American Mosquito Control Association as early as 2005. No scientific work has demonstrated that oral intake of vitamin B1 has any effect on a person's attractiveness to mosquitoes. Yet this "tip" still appears on discussion forums and in articles about natural protection.
Another widespread myth is the ultrasonic mosquito repeller – whether in the form of a phone app or an electronic device. An extensive review of studies published by the Cochrane Database conclusively determined that ultrasonic repellers have no demonstrable effect on mosquito behavior. It is one of the most persistent myths in the field of insect protection, and manufacturers of these devices profit from the fact that the placebo effect is strong – when you believe a device is protecting you, you notice the occasional bite less.
The position of garlic is also interesting. The idea that consuming garlic repels mosquitoes is deeply rooted in the folk traditions of many cultures. Science says a clear no to this. A study from the University of Connecticut in 2005 tested the effect of garlic consumption on attractiveness to mosquitoes and found no statistically significant difference. Garlic is great for the immune system and taste buds, but it doesn't work as a repellent.
If you decide to prepare a homemade repellent, there are several principles that will increase your chances of success. The foundation should be a quality essential oil with a proven effect – ideally lemon eucalyptus oil with a high citriodiol content, or alternatively geraniol. Coconut oil has proven effective as a carrier oil, as it itself exhibits mild repellent properties due to its lauric acid content, as shown by a study published in Scientific Reports in 2018.
A typical homemade repellent recipe looks approximately like this: mix 10–15 drops of lemon eucalyptus essential oil with 30 ml of coconut oil, optionally adding a few drops of lavender oil for a more pleasant scent. Apply the mixture to exposed skin and expect to repeat the application every two hours, or more frequently if sweating. It's important to note that essential oils can trigger an allergic reaction in sensitive individuals, so always first test a small amount on the inside of your forearm.
As entomologist Jonathan Day from the University of Florida said: "The best repellent is the one you actually use." And there's hidden wisdom in that. The most effective product in the world is useless if you leave it at home because you dislike its smell or consistency. If a natural repellent motivates you to actually use protection, it has its value – you just need to know its limits.
Beyond repellents themselves, there are other strategies that significantly reduce the risk of mosquito bites or tick attachment. Light-colored clothing with long sleeves is one of the most effective measures against ticks – a tick is easier to spot on light fabric, and dense weave makes it harder for the tick to reach the skin. Tucking your trouser legs into your socks may not look like something out of a fashion magazine, but in a forest full of ticks, it's one of the smartest things you can do.
A thorough body check after returning from nature remains the absolute foundation of tick-borne disease prevention. A tick typically needs to be attached for at least 24 hours to transmit Lyme disease, so timely removal dramatically reduces the risk of infection. With tick-borne encephalitis, the situation is worse – the virus is transmitted practically immediately after attachment, which is why vaccination should be considered in endemic areas.
The world of natural repellents isn't black and white. There are substances with real, scientifically supported effects that can serve as a reasonable alternative to synthetic products in many everyday situations. At the same time, the internet overflows with misinformation and "guaranteed old wives' tales" that have no basis in evidence. The key is being informed and using good judgment – knowing when spraying yourself with citronella is enough and when it's wiser to reach for a product containing DEET or icaridin. In both cases, it's about the same thing: protecting your health and enjoying summer without unpleasant consequences.
