How long does Botox last? Duration and why it wears off

After "how long does it take to work?", the next question is almost always "how long does it last?". It is one of the basics covered on our complete introduction to botulinum toxin. Here too, everything depends on the family of toxin used, and the answer is well explained by what happens in the nerve.

The short answer

The effect of botulinum toxin is always temporary. How long it lasts depends mainly on the type of toxin:

• long-acting toxin (type A): usually 3–4 months, and up to 6 months for some products^1,2,3;
• short-acting botulinum toxin (serotype E), approved since 2026: usually 2–3 weeks⁵.

These durations come from the official labels and from trials conducted on frown lines. They describe a general trend, not a guarantee for each person.

Long-acting toxin: how long does it last?

The labels of type A toxins give similar durations, with some differences from one product to another. One reports efficacy demonstrated up to 4 months¹, others an effect that persists up to 4 months⁸ or lasts between 12 and 16 weeks⁴. Two products have shown an effect up to 6 months after the injection^2,3. So remember 3–4 months as a rule, up to 6 months depending on the product^1,2.

The duration stated in a label does not mean that the effect stays the same throughout that period. After the peak effect, reached between week 2 and week 4^1,8, the effect gradually decreases: movement returns little by little, then the line deepens again.

Short-acting botulinum toxin: how long does it last?

The short-acting toxin has a very different profile. Its label states that recovery generally occurs within 2–3 weeks⁵. In the phase 2b trial, at the highest dose, the proportion of patients responding to treatment fell from 93.3% at day 7 to 33.3% from day 14⁹.

This short duration is a characteristic, not a flaw: it corresponds to a different use. The label specifies that, due to its early onset of effect and short duration, this toxin should be used occasionally⁵. As of 9 October 2026, it is approved in the European Union (since 15 July 2026) and in Canada (since 22 June 2026), for frown lines only^11,12. To find out how quickly each of the two families works, see our page on the time it takes for each toxin to work.

Why does the effect wear off?

Botulinum toxin destroys neither the muscle nor the nerve. It temporarily blocks the release of acetylcholine by cutting a protein in the nerve ending, SNAP-25^1,5. The effect disappears when transmission between nerve and muscle is restored.

The nerve recovers in two stages

Reference studies have described this recovery^6,7. In a first stage, the blocked nerve ending grows small branches, called sprouts, which reach the muscle and restore transmission. In a second stage, the original nerve ending recovers its ability to release acetylcholine, and the branches that are no longer needed disappear^6,7.

The labels describe the same thing in their own words. For a type A toxin, recovery normally takes place within 12 weeks, as the nerve endings restore their connections¹. For the short-acting toxin, recovery occurs as primary nerve terminals recover⁵.

Why one lasts longer than the other

Both toxins cut the same protein, SNAP-25, but the active part of the type A toxin stays much longer in the nerve ending⁶. That of the type E toxin is recognised and cleared more quickly by the cell’s breakdown systems, whereas that of the type A toxin escapes them⁶. The type E toxin also removes a larger portion of SNAP-25 than the type A toxin⁶. These molecular differences are detailed on our page about what research says about botulinum toxins.

What makes the duration vary?

Several factors are documented:

• the product: the labels of type A toxins do not all give the same duration^1,2,4;
• the family of toxin: long-acting (type A) or short-acting (serotype E)^1,5;
• the dose: in the phase 2b trial of the short-acting toxin, the proportion of responders increased with the dose⁹, but the labels do not quantify the effect of dose on duration;
• more rarely, antibodies: in a few people, antibodies can make the toxin less effective; high doses and closely spaced injections make them more likely^1,10.

Other factors are often mentioned, such as the area treated, muscle strength or age, but the labels do not allow their effect to be quantified. The published durations mainly concern frown lines; for off-label areas, no label gives a duration.

How often should an injection be repeated?

For type A toxins, the labels require an interval of at least 3 months between two sessions^2,8. This interval is not an obligation to have another injection at that point: many people wait until the effect has clearly decreased.

For the short-acting toxin, the label specifies occasional use⁵. Retreatment at intervals shorter than 6 weeks has not been evaluated, nor have more than 3 consecutive injections beyond 18 weeks⁵. A type A toxin injected less than 30 days after the short-acting toxin has not been evaluated either⁵.

In every case, do not bring sessions closer together on your own: giving doses too close together or too high may increase the risk of antibody formation¹. The schedule is decided with your doctor.

What happens when the effect wears off?

When the effect fades, the muscle gradually regains its strength and the line caused by movement reappears^1,5. The labels describe no "rebound" effect, and there is no obligation to continue the injections: you can stop at any time. People often ask whether the face ages faster after stopping; we found no reliable source showing this.

If you have an important date, the relationship between onset and duration matters as much as each of them: our page on timing an injection before an event describes these reference points for both families of toxin, without recommending one over the other.