Shelf life of Advantage flea control?

What is the shelf life of Advantage for cats? How long does it retain its effectiveness? Thanks.

You apply it once a month to your animal and it has a shelf life of 2 years at room temperature

Subject: Response from Bayer Animal Health
To: [email protected]
From: "Kim Mathews" <[email protected]>
Date: Fri, 19 Apr 2002 07:26:21 -0500

Dear Mr. Frank:

Thank you for your posting on our website. Advantage has no expiration date. Based upon extensive stability studies, we know Advantage remains stable for at least five years from the date of purchase. Hope this helps!

Sincerely,

Kim Mathews, RVT
Veterinary Services Associate
Bayer Corporation, Animal Health Division

If shelf life of the product is five years, the real question is how long it's been on the shelf..

My cat is 3.5 years old, the product was purchased when he was 2 month old for his mother. I just used the last one on him a week ago with little effect- I found 5 live fleas in a past couple of days(3 today).  About to go buy a new pack since it worked magic before, but a bit disappointed in a failure this time around. 

Orangejunicat said:

 
If shelf life of the product is five years, the real question is how long it's been on the shelf..

My cat is 3.5 years old, the product was purchased when he was 2 month old for his mother. I just used the last one on him a week ago with little effect- I found 5 live fleas in a past couple of days(3 today).  About to go buy a new pack since it worked magic before, but a bit disappointed in a failure this time around. 

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Heat and cold will cause a product, especially a chemical product to break down much faster than normal. Light will do that also.

Advantage is considered to have no real expiration. However despite my being a user of this product faithfully for many years, I have found it is not effective as it used to be.

Same with Frontline, which has been not working for much longer.

Time for them to rework their formula!