(DAILYMAIL) — It is the £200-a-time beauty treatment many women swear by to smooth out their wrinkled foreheads and crow’s feet.

But those relying on Botox to hold back the years could be wasting their money – because they are becoming immune to the injections, warn scientists.

They say the drug, a type of neurotoxin, is failing to freeze the facial muscles of some patients as well as it did before, or for as long.

Many women are even developing antibodies to some types of the treatment, meaning it stops working altogether.

Note: Read our discussion guidelines before commenting.