Injectable · Botulinum Toxin · Facial Lines

Botox

How this page was made
This page was written with AI assistance and reviewed against the sources listed under References below. It is general information only, not medical advice. See our full disclaimer for how SHEA creates and reviews treatment information.
01

What it is

Botox is the brand name for onabotulinumtoxinA, one of several botulinum toxin products used in aesthetic medicine. Botulinum toxin temporarily reduces activity in the muscles into which it is injected.

For cosmetic facial treatment, this can temporarily reduce the appearance of lines associated with muscle movement. In the United States, BOTOX Cosmetic is FDA-approved for moderate to severe frown lines between the eyebrows, crow’s feet, forehead lines, and platysma bands in adults.

Other botulinum toxin products are also available. Their formulations and potency units are not interchangeable, so evidence, dosing, and regulatory status should be considered for the specific product being used.

02

Why people consider it

  • They are looking into treatment for facial lines associated with repeated muscle movement, such as frown lines, forehead lines, or crow’s feet
  • They are considering treatment of prominent masseter muscles to reduce lower-face width
03

What the experience is like

Botulinum toxin is injected into selected muscles using a fine needle. The number and location of injections depend on the area being treated and the product used.

The effect is not immediate. With BOTOX Cosmetic, muscle effects begin after treatment and become more apparent over the following days. The effect is temporary and gradually diminishes as muscle activity returns.

04

Limitations & considerations

  • Results vary by treatment area, product, dose, injection approach, and individual response
  • For BOTOX Cosmetic specifically, known hypersensitivity to a botulinum toxin preparation or its ingredients and infection at the proposed injection site are listed as contraindications
  • People with certain neuromuscular disorders, including myasthenia gravis or Lambert-Eaton syndrome, may be at increased risk of clinically significant effects and should discuss this with the treating clinician
  • There are no adequate human data establishing the developmental risk of BOTOX Cosmetic during pregnancy
  • Botulinum toxin effects can occasionally extend beyond the injected area and cause clinically important weakness or problems with swallowing, speaking, or breathing
  • Masseter treatment is a distinct use with its own evidence, dosing, and potential effects and should not be assumed to have the same evidence or regulatory status as treatment of FDA-approved facial-line indications
Evidence note
OnabotulinumtoxinA has been evaluated in multiple randomized, placebo-controlled clinical trials for cosmetic facial lines. Current US prescribing information for BOTOX Cosmetic includes indications for moderate to severe glabellar lines, lateral canthal lines, forehead lines, and platysma bands. The product label also emphasizes that potency units for BOTOX Cosmetic are specific to that preparation and cannot be directly converted to units of other botulinum toxin products.
Botulinum toxin treatment of masseter muscle prominence has also been studied separately. The randomized trial cited below (180 participants, with 114 continuing into a 24-week open-label extension) evaluated prabotulinumtoxinA specifically and reported reductions in masseter thickness. Two of its ten authors are affiliated with the manufacturer of that product, Daewoong Pharmaceutical. This evidence involves a specific botulinum toxin product and protocol, and findings from one formulation should not automatically be transferred to every botulinum toxin product or treatment protocol.

References

Peer-reviewed literature and US regulatory safety information.

1. Carruthers A, Carruthers J. Botulinum toxin type A: history and current cosmetic use in the upper face. Seminars in Cutaneous Medicine and Surgery, 2001;20(2):71–84.
Peer-reviewed · Clinical review
2. US prescribing information. BOTOX Cosmetic (onabotulinumtoxinA) — indications, contraindications, warnings, pregnancy data, and clinical studies.
US regulatory · Current product labeling
3. Seok J, Koh YG, Hong JK, et al. Efficacy and safety of prabotulinumtoxinA in subjects with benign masseteric hypertrophy: a double-blind, randomized, placebo-controlled, multicenter, phase 3 trial and open-label extension study. Dermatologic Surgery, 2024;50(6):527–533.
Peer-reviewed · Phase III randomized trial (n=180) · Product-specific masseter evidence · Manufacturer-affiliated authors
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