Prospective, double-blind, randomized, parallel-group, dose-ranging study of botulinum toxin type A in men with glabellar rhytids

Dermatol Surg. 2005 Oct;31(10):1297-303. doi: 10.1111/j.1524-4725.2005.31206.


Background: The effective dose for treating glabellar lines with botulinum toxin type A in men has not been studied adequately.

Objective: To compare the safety, efficacy, and duration of response of four doses of botulinum toxin type A on glabellar rhytids in men.

Methods: Eighty men were randomized to receive a total dose of either 20, 40, 60, or 80 U of botulinum toxin type A (BOTOX, BOTOX Cosmetic, or Vistabel, Allergan, Inc., Irvine, CA, USA) in the glabellar area. Glabellar lines were assessed at rest and maximum frown by a trained observer at baseline, 2 and 4 weeks, and monthly thereafter. Patients provided self-evaluations at the same visits. Adverse events were monitored throughout.

Results: The 40, 60, and 80 U doses of botulinum toxin type A were consistently more effective in reducing glabellar lines than the 20 U dose (duration, peak response rate, improvement from baseline). There was a dose-dependent increase in both the response rate at maximum frown and the duration of effect assessed by the trained observer. In addition, the participants reported a dose-dependent reduction in the ability to frown, improvement in their global assessment, and increased feelings of attractiveness, self-confidence, and satisfaction. The incidence of adverse events was not increased with higher doses.

Conclusion: Male participants with glabellar rhytids benefit from starting doses of at least 40 U of botulinum toxin type A.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Botulinum Toxins, Type A / administration & dosage*
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Humans
  • Male
  • Middle Aged
  • Neuromuscular Agents / administration & dosage*
  • Prospective Studies
  • Recurrence
  • Rhytidoplasty*
  • Skin Aging / drug effects*
  • Treatment Outcome


  • Neuromuscular Agents
  • Botulinum Toxins, Type A