How long does Seresto collar take to kill fleas

The Seresto flea and tick collar is effective in killing fleas within 24 hours after being put on the dog, and continues to protect your pet for 8 months. The active ingredients in Seresto are two innovative chemicals – imidicloprid and flumethrin – that combine to form a powerful barrier against pre-adult and adult fleas, ticks, lice and other biting insects. Imidicloprid repels fleas while Flumethrin quickly kills them when they attempt to bite your pet.

Clinical studies have shown that 98% of all fleas present in dogs wearing an activated Seresto collar were killed within 7 days. Additionally, within the first 4 weeks, 100% of all ticks present on the dogs wearing an activated Seresto collar were killed. After 8 months of continuous use, the amount of fleas reduced by 99.9%.

In short, it takes 24 hours for the Seresto Collar to start killing existing fleas on your dog’s body and continuous use for 8 months gives your dog 99.9% protection from further infestations.

What is Seresto and How Does It Work?

Seresto is a flea and tick collar that provides 8 months of continuous protection against fleas and ticks on dogs and cats. It contains two active ingredients: imidacloprid, which kills adult fleas, and flumethrin, which repels and kills ticks, larvae, and nymphs. By killing the adult fleas, Seresto also prevents them from reproducing or laying eggs.

So how does it work? The Seresto collar gradually releases a low level of active ingredients in an odorless vapor that your pet wears around their neck like any other collar. With gradual release of these active ingredients over time, the vapor is slowly released onto your pet’s fur and skin to create an effective yet safe shield against fleas and ticks. Not only does this provide complete coverage for your pet in areas where traditional topical treatments might not reach, but it also kills existing parasites as well as those that come into contact with it. Plus, since the product will last up to 8 months even if you bathe your pet or expose them to rain or sunlight, you don’t have to worry about frequently reapplying the product!

Do Seresto Collars Instantly Kill Fleas?

No, Seresto collars do not instantly kill fleas. The product contains an active ingredient called imidacloprid, which works to provide a slow release of the chemical over time. This slow release allows the collar to be effective up to 8 months and serve as a long-term solution for flea control.

It usually takes the collar between 12-24 hours after being applied to begin having a noticeable effect on adult fleas on your pet. However, it may take up to several days for full effectiveness against larvae and eggs, so you may still see some fleas for several days as the remaining insects are killed off or vacate your pet’s environment entirely.

How Long does Seresto Take to Kill Fleas?

The Seresto collar is designed to kill fleas and ticks on contact. How long it takes for the collar’s flea-killing effect to kick in depends on the number of fleas or ticks present, the size of those pests, how well it is applied, and other factors.

Typically, it takes 24-48 hours for the active ingredients in the Seresto Collar (imidacloprid and flumethrin) to be absorbed into your pet’s skin and fur. During this time, fleas are killed as they come in contact with your pet’s body. Once it gets absorbed completely into your pet’s skin,about 95% of existing fleas will be killed within 24 hours after exposure. It also kills any new fleas that come into contact with your pet before they can lay eggs – meaning less fleas over time!

The effects of a single Seresto collar usually lasts for 8-10 months or until its physical integrity has been compromised by your pet’s daily activities (e.g., Playing outside). So rest assured – as long as you take proper care of your collar you can enjoy 8-10 months of protection from pesky parasites!


Seresto collars are a safe, long-lasting option for controlling fleas in pets. If used correctly and according to the product’s instructions, they can help eliminate your pet’s flea problem quickly and effectively.

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