There are few studies on topical scar treatments, and most of these do not report any side effects. Based on the scant available evidence, the charts below show the chances of developing side effects from topical scar treatments.3

Certain/Likely Side Effects (% = Incidence)

None reported

Possible/Rare Side Effects

SHORT TERM Human synthetic EGF only: Acne flare-upup to 8.3%*

Studies:   

One study has looked at the side effects of topical treatments for atrophic scars.

  • Study 1:

    • Authors: Stoddard et al.3
    • Total # of patients: 12
    • # of female patients: 11
    • # of male patients: 1
    • Age of patients: 18-62 Average: 32.5
    • Type of treatment: Topical synthetic EGF serum
    • Duration of treatment and follow-up: 12 weeks of treatments twice a day
    • Side effects: Acne flare-up: 8.3%

* All patients had Asian skin type.

Study 1: In a study published in 2017 in the Journal of Drugs in Dermatology, Stoddard and colleagues treated 12 patients with atrophic (indented) acne scars. All patients were people of color and were instructed to apply topical serum containing synthetic EGF to their faces twice a day for 12 weeks. One patient experienced an acne flare-up and quit the study early. The remaining 11 patients completed the study and did not report any side effects.3

References
  1. Morganroth P, Wilmot AC, and Miller C. Over-the-counter scar products for postsurgical patients: disparities between online advertised benefits and evidence regarding efficacy. Journal of the American Academy of Dermatology. 61(6), e31-47 (2009).
  2. Levy LL, and Zeichner JA. Management of acne scarring, part II. A comparative review of non-laser-based, minimally invasive approaches. Am J Clin Dermatol. 13(5), 331-340 (2012).
  3. Stoddard MA, Herrmann J, Moy L, and Moy R. Improvement of Atrophic Acne Scars in Skin of Color Using Topical Synthetic Epidermal Growth Factor (EGF) Serum: A Pilot Study. Journal of drugs in dermatology: JDD. 16(4), 322 (2017).