Description
BOTOX 100 Allergan Units is a botulinum toxin type A. Each vial contains 100 Allergan Units of botulinum toxin type A derived from Clostridium botulinum. Following reconstitution and administration, the neurotoxin acts at peripheral cholinergic nerve terminals by inhibiting acetylcholine release at the neuromuscular junction. This produces temporary chemical denervation and reduced activity of the targeted muscle.
The UK-authorised product has several therapeutic indications. In aesthetic medicine, BOTOX is indicated for the temporary improvement in the appearance of moderate to severe glabellar lines, lateral canthal lines (crow’s feet), forehead lines and platysma prominence in adults where the severity has an important psychological impact.
BOTOX should be administered only by an appropriately qualified healthcare practitioner with relevant expertise and the equipment required for the specific indication.
There are also differences in formulation, licensed indications, administration instructions and dosing. For example, the authorised BOTOX aesthetic indications include glabellar lines, crow’s feet, forehead lines and platysma prominence, while the licensed indications for other botulinum toxin products may differ.
Treatment Areas / Indications
The current UK SmPC lists the following aesthetic indications for BOTOX:
- Glabellar lines between the eyebrows at maximum frown.
- Lateral canthal lines (crow’s feet) at maximum smile.
- Forehead lines at maximum eyebrow elevation.
- Platysma prominence
BOTOX also has authorised medical indications covering certain neurological disorders, chronic migraine, bladder disorders and severe primary axillary hyperhidrosis.
Usage / Administration
BOTOX 100 Units Dilution
The appropriate concentration depends on the authorised indication and dosing schedule. The manufacturer states that the correct diluent volume must be used for the selected vial presentation to help prevent dosing errors.
BOTOX is intended for single use only, and unused reconstituted product should be discarded.
Ingredient List
- Active ingredient: Botulinum toxin type A — 100 Allergan units per vial.
The product is supplied as a thin white powder that may be difficult to see at the bottom of the transparent vial.
Presentation & Longevity
BOTOX 100 Allergan Units is supplied as a single clear glass vial containing 100 Allergan Units of botulinum toxin type A, together with a package leaflet. Packs may contain one, two, three or six cartons, although not all pack sizes may be marketed.
The unopened product has a 3-year shelf life. Refrigerated at 2–8°C
After reconstitution, stability has been demonstrated for up to 24 hours at 2–8°C. From a microbiological perspective, immediate use is recommended. Each vial is for single use only.
For aesthetic facial indications, the documented duration varies according to the treatment area. BOTOX has demonstrated improvement in glabellar lines for up to 4 months, while the manufacturer reports improvement in primary axillary hyperhidrosis lasting approximately 4–7 months following 50 Units per axilla. Individual response varies by indication and patient.
Safety Notes / Contraindications
BOTOX is contraindicated in patients with:
- Known hypersensitivity to botulinum toxin type A or any listed excipient.
- Infection at the proposed injection site.
The MHRA issued an updated safety communication in July 2026 concerning rare cases of iatrogenic botulism after therapeutic or cosmetic use of botulinum toxin products. The MHRA advises that authorised products and product-specific administration guidance should be followed.
BOTOX is not recommended during pregnancy, and use during breastfeeding cannot currently be recommended according to the UK SmPC.
Regulatory Status
BOTOX 100 Allergan Units is a UK-authorised prescription-only medicine (POM) rather than a dermal filler or CE/UKCA medical device. The UK product information identifies AbbVie Ltd as the Marketing Authorisation Holder and Allergan Pharmaceuticals Ireland as the manufacturer.
The current UK SmPC was updated on 15 May 2026 and identifies the product as BOTOX 100 Allergan Units powder for solution for injection.
BOTOX potency is expressed in Allergan Units. These units are product-specific and must not be treated as interchangeable with units from other botulinum toxin preparations.
FAQ
1. What is BOTOX 100 Allergan Units?
BOTOX 100 Allergan Units is a prescription-only medicine containing 100 Allergan Units of botulinum toxin type A per vial. Its active neurotoxin temporarily inhibits acetylcholine release at cholinergic nerve terminals, reducing neuromuscular transmission in the treated area. The UK-authorised product has several therapeutic indications, including specified aesthetic facial lines and platysma prominence. Administration should be performed by an appropriately qualified healthcare practitioner with relevant expertise in the indication being treated.
2. What is BOTOX 100 units used for?
For aesthetic use, the UK SmPC authorises BOTOX for temporary improvement in moderate to severe glabellar lines, lateral canthal lines, forehead lines and platysma prominence in adult patients where the severity has an important psychological impact. BOTOX also has licensed medical indications involving neurological disorders, chronic migraine, bladder disorders and severe primary axillary hyperhidrosis. The appropriate dose and administration method depend on the specific authorised indication.
3. How long does BOTOX 100 units last?
The duration depends on the indication and individual response. For glabellar lines, the UK product information reports significant reduction in line severity for up to 4 months, with improvement generally occurring within one week. For primary axillary hyperhidrosis, the documented effect is approximately 4–7 months following 50 Units per axilla. These figures represent clinical data rather than a guaranteed duration for every patient. Repeat treatment should follow the authorised interval for the specific indication.
4. Is BOTOX 100 Allergan Units equivalent to 100 units of another toxin?
No. BOTOX uses Allergan Units, which are specific to the BOTOX product. The UK SmPC explicitly states that botulinum toxin units are not interchangeable from one product to another. Although BOTOX, Bocouture and Azzalure all contain botulinum toxin type A, their formulations, potency units, licensed indications and dosing instructions differ. Consequently, BOTOX 100 Allergan Units should not be assumed to correspond directly to 100 units of another botulinum toxin preparation.
