Anti-wrinkle injections start working two to three days after treatment and reach their full effect at ten to fourteen days. Nothing changes on the day itself, which surprises people. Most clinics book a review at two weeks, because that is the earliest point at which the result can be judged and a top-up given if one area has under-responded.
Why isn’t it instant?
The medicine, botulinum toxin type A, has to be taken up by the nerve endings in the treated muscle and then block the chemical that tells the muscle to contract. That process takes days, not minutes. The injection itself puts the medicine in the right place; the body does the rest at its own pace.
This is different from dermal fillers, which show their effect immediately because they add volume rather than change how a muscle works. If you have had both, the contrast can make anti-wrinkle injections feel slow.
Day by day: the first two weeks
Treatment day. Small raised bumps at each injection point, like insect bites, which flatten within thirty minutes. Perhaps a pinprick of blood or a tiny bruise. Your face moves exactly as before. Mild headache is common in the first few hours.
Days 1 to 2. Nothing visible. Some people feel a slight heaviness or tightness in the treated area, which is the first sign the muscle is weakening. Bruises, if any, are at their most obvious.
Days 3 to 5. The muscle starts to feel harder to use. You may notice that frowning takes more effort, or that your forehead moves less when you raise your brows. Lines look softer on movement but are still there at rest.
Days 5 to 7. Clear weakening. Most people would say the treatment “has worked” by now, though it is not yet at full strength. If one side seems ahead of the other, this is the normal stage for it.
Days 10 to 14. Full effect. The treated muscle is as relaxed as it will get, lines on movement are at their softest, and lines at rest have had a week or more to start smoothing out. This is when your result should be assessed and photographed.
Weeks 2 to 4. Lines at rest continue to soften as the skin, no longer folded dozens of times a day, gradually recovers. Deeply etched lines improve most slowly and may not fully disappear.
What affects how fast it works?
The area. Crow’s feet and frown lines often show an effect by day three. The forehead can take a day or two longer, partly because it is treated with a lighter dose.
The dose. A higher dose tends to take hold slightly faster as well as last longer. A very low dose can take the full fourteen days to show anything.
The product. Several brands are licensed in the UK. Some practitioners find one works a day or so faster than another, but at equivalent doses the differences are small.
You. Muscle size, how strongly you use the muscle, and individual variation all play a part. People who have had several treatments sometimes report a faster onset, probably because the muscle is already weaker.
When to worry, and when not to
Normal and no action needed: no visible change before day three; mild headache for a day; small bruises; slight asymmetry before day fourteen; a feeling of tightness or heaviness in the first week.
Normal but worth mentioning at your review: one area clearly weaker than another at two weeks; a result that seems much lighter than expected; an eyebrow that sits higher on one side.
Go back to the clinic: a drooping eyelid or heavy brow (ptosis). This is uncommon and happens when a small amount of medicine affects a neighbouring muscle. It is temporary, usually improving within three to six weeks, and your practitioner may be able to prescribe eye drops that help in the meantime. Do not have more injections to “balance” it without a proper assessment.
Seek urgent medical help: difficulty swallowing, speaking or breathing, blurred or double vision, or weakness away from the treated area in the days after treatment. These are rare but serious. Contact the clinic and call NHS 111; call 999 if breathing is affected.
The two-week review
A review at ten to fourteen days is the mark of a good clinic. The practitioner compares your result with the pre-treatment photographs, checks for unevenness, and if one area has under-responded adds a few units. Most clinics include a modest top-up in the original price; ask when you book.
Do not accept a top-up before day ten. The medicine has not finished working, and adding more at that stage risks over-treating the area once the first dose takes full effect.
Planning around an event
Book treatment two to three weeks before a wedding, holiday or photographs. That gives the full effect time to develop, any bruising time to fade, and leaves room for the two-week review. If it is your first treatment, allow three weeks, because you cannot predict how your face will respond and a top-up is more likely.
What happens next
Once the full effect is in, it holds for roughly two months before movement gradually starts to return. Our guide to how long anti-wrinkle injections last covers the months that follow, and the aftercare guide explains what to do and avoid in the first few days. Use the clinic listings on this site to find a registered practitioner who offers a two-week review as standard.
Sources
- NHS: Botulinum toxin injections
- Electronic Medicines Compendium: summaries of product characteristics for UK-licensed botulinum toxin type A products (onset of effect), medicines.org.uk