Isotretinoin 5 mg daily for low-grade adult acne vulgaris--a placebo-controlled, randomized double-blind study

J Eur Acad Dermatol Venereol. 2014 Jun;28(6):747-54. doi: 10.1111/jdv.12170. Epub 2013 Apr 26.


Background: Despite acne persisting into adulthood in up to 50% of the population, very few therapeutic studies have been performed in this age group.

Objectives: To assess the efficacy of 5 mg/day isotretinoin in adult acne.

Methods: An investigator initiated, industry-sponsored, randomized, double-blind, placebo-controlled, parallel-group clinical study of isotretinoin 5 mg/day in the treatment of low-grade adult acne for 16 weeks followed by an open-label phase of 16 weeks. Group 1 received 32 weeks of 5 mg isotretinoin/day; Group 2 first received 16 weeks of placebo, followed by 16 weeks open-label 5 mg isotretinoin/day. Patients were followed for a further 10 weeks off treatment. The primary end-point was the difference in acne lesion count and disability score after 16 weeks isotretinoin compared to placebo. Secondary end-points included differences in these counts/scores after 32 weeks of isotretinoin compared to baseline, and after 10 weeks off treatment, compared to end of treatment (week 32).

Results: There were highly significant differences (P < 0.0001) in acne lesion count, Dermatology Life Quality Index and self-assessment after 16 weeks of isotretinoin, compared to placebo (both per protocol and intention to treat). Acne lesions fell significantly, within 4 weeks of 5 mg isotretinoin/day (Group 1) and continued to fall during 32 weeks of treatment [acne lesion count (mean ± SD): 11.3 ± 8.1 (baseline), 3.6 ± 5.5 (week 16), 1.3 ± 3.1 (week 32), P < 0.0001)]. There was a similar significant reduction in acne lesion count in Group 2, but only from week 20, 4 weeks after starting open-label 5 mg isotretinoin. Adverse effects were minimal.

Conclusions: Isotretinoin 5 mg/day is effective in reducing the number of acne lesions, and improving patients dermatologic quality of life, with minimal adverse effects.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acne Vulgaris / drug therapy*
  • Adult
  • Dermatologic Agents / administration & dosage*
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Humans
  • Isotretinoin / administration & dosage*
  • Male
  • Middle Aged
  • Placebos
  • Severity of Illness Index


  • Dermatologic Agents
  • Placebos
  • Isotretinoin

Supplementary concepts

  • Acne, Adult