Efficacy and safety of oral silymarin in comparison with oral doxycycline and their combination therapy in the treatment of acne vulgaris

Dermatol Ther. 2019 Nov;32(6):e13095. doi: 10.1111/dth.13095. Epub 2019 Oct 21.


Two factors of oxidative stress and inflammatory processes are implicated in pathogenesis of acne vulgaris. Silymarin has antioxidant and anti-inflammatory activities. This study was done to evaluate the effect of oral silymarin in the treatment of acne vulgaris compared to doxycycline and also their combination therapy. This randomized controlled trial was performed on 60 patients with acne vulgaris were divided into three groups of 20 patients, including: Silymarin (Group 1), Doxycycline (Group 2), and both compounds (Group 3). The patients' response was monitored every month and the lesions were evaluated using photography and two methods of Global Acne Grading system (GAGS) and Acne Severity Index (ASI). According to the results, the response to silymarin was not significantly different with doxycycline in the GAGS index (p = .260), but was lower in the ASI (p = .021). In this study, the synergistic effects of silymarin and doxycycline combination have been investigated in comparison with doxycycline. Although the improvement was more favorable in combination group, there was no statistically significant difference (p = .9 in ASI and p = .5 in GAGS). The results of our study suggest that although the silymarin monotherapy is not as effective as doxycycline for the treatment of acne vulgaris, it can be a therapeutic option.

Keywords: acne vulgaris; anti-inflammatory; antioxidant; doxycycline; silymarin.

Publication types

  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Acne Vulgaris / drug therapy*
  • Acne Vulgaris / pathology
  • Administration, Oral
  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / adverse effects
  • Antioxidants / administration & dosage
  • Antioxidants / adverse effects
  • Doxycycline / administration & dosage*
  • Doxycycline / adverse effects
  • Drug Synergism
  • Drug Therapy, Combination
  • Female
  • Humans
  • Male
  • Severity of Illness Index
  • Silymarin / administration & dosage*
  • Silymarin / adverse effects
  • Treatment Outcome
  • Young Adult


  • Anti-Bacterial Agents
  • Antioxidants
  • Silymarin
  • Doxycycline