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Botox injection reduces immediate sebum production, increases sebum away from injection point

In a study of two Botox dosing groups, researchers found intramuscular injection significantly reduced sebum production at the injection site but increased sebum production within a 2.5-cm radius of the surrounding skin area.

The study included 42 women with forehead rhytides who were randomly assigned to receive 10 units (0.25 mL, group one) or 20 units (0.5 mL, group two) of Botox (onabotulinumtoxinA, Allergan) administered at five injection sites in the forehead. Mean patient age was 41 years in group one and 48.8 years in group two.

The researchers used a Sebumeter (Courage+Khazaka electronic) to measure sebum production at baseline and post-treatment. Patients were assessed before the injection, at baseline and at weeks 2, 4, 8 and 16.

Among patients in group one, the average sebum production changes from baseline at the 2-, 4-, 8- and 16-week follow-ups were 25.25%, 45.84%, 17.59% and 9.62%, respectively, within the central 0.5-cm radius surrounding the injection site, which the researchers defined as area one. For group two, the average percentage change from baseline at weeks 2, 4, 8 and 16 were 46.95, 34.72, 27.36 and 10.3, respectively, for area one, according to the researchers.

In area two, which the researchers defined as a 1-cm radius from the injection site, patients in group one demonstrated changes in average sebum production from baseline of 0.58%, 12.12%, 9.78% and 21.05% at weeks 2, 4, 8 and 16, respectively. Patients in group two demonstrated average changes of 0.83%, 1.4%, 2.17% and 29.36%, respectively, at the same time points.

The researchers determined sebum production had a positive correlation with the distance away from the injection point. The sebum production in area three - defined as the outermost area, with a radius of 1 cm outside the toxin diffusion area - was higher than in area two, which was higher than area one, with the most difference occurring at weeks 2, 4, and 8.

The efficacy did not improve with higher injection doses, and sebum production recovered to normal levels at the 16-week follow-up for both groups, according to the researchers.

Average sebum production was greatest in patients younger than 40 years of age. - by Abigail Sutton

Disclosure: The researchers report no relevant financial disclosures.