Anti-wrinkle injections start working 1-5 days after injection. The peak effect of the anti-wrinkle injections is at 2 weeks, and usually last up to 3-4 months.
Anti-wrinkle injections are considered of a substance called Botulinum Toxin Type-A. Once injected into the specific muscle, it blocks a neurotransmitter called acetylcholine from being released between the nerve and the muscle. Once acetylcholine has temporarily been blocked, the muscle will not contract. In clinical studies, the muscle contraction may start to slightly come back at about the 60 day mark after injection, then full muscle contraction should be back at the 90 day mark. Everyone is slightly different, and depending on the dose injected, this may vary between patients. Once the muscle contraction completely comes back, the muscle will contract exactly how it used to before injection, in time. This means, to prevent wrinkles, repeat injections will be needed to give long-term results.