Journal of Cosmetic Science | Vol. 70 No. 1
Authored by Christoph Gfeller, George Hardie, Gilbert Shanga, and Harish Mahalingam
This report explores dry-skin models to assess the potential of a new lip balm formulation to hydrate dry skin or lips, and presents sun protection factor (SPF) values for five new lip balm formulations. Evaporimeter [for transepidermal water loss (TEWL)], Skicon®, and Corneometer® were used to measure hydrating effects of lip balm formulations in a dry-skin leg model, and TEWL, DermaLab® Moisture Meter, Corneometer®, and visual assessments were used with a dry-lip model. SPF studies were conducted in accordance with either the U.S. Food and Drug Administration monograph final rule or international standard ISO 24444. Data from dry-skin leg model demonstrate that a new lip balm formulation significantly improves skin hydration compared with untreated leg skin and four comparator products. Data obtained from a dry-lip model proved unreliable. Five new lip balm formulations exhibited sunscreen capability; however, they did not meet the intended SPF. There were no product-related adverse events with the formulations. Although the new lip balm formulation improved hydration, data from a novel dry-lip model proved unreliable therefore further testing is required to confirm these benefits. Five new lip balm formulations provided sunscreen capability but did not meet the intended SPF, and will undergo reformulation and retesting.
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