Silicone or glycerin based gel sheets have been used by medical professionals for nearly 30 years to prevent the formation of hypertrophic or keloid scars following injury or surgery, and to reduce the size of existing scars. This product is usually self-adhesive on the silicone or glycerin side, and the outer layer is made of a fabric or a non-adhesive transparent film. The specific mechanism that results in these gel sheets helping to prevent and reduce the size of hypertrophic and keloid scars has not been identified, however studies continue. While silicone or glycerin gel sheets may be effective on any wound or scar, they have been shown to be most effective on hypertrophic and keloid scars.
Hypertrophic scars occur when the body produces excess collagen at the site of an injury or wound. Excess collagen causes the scar to rise above the surrounding skin, but hypertrophic scars are confined within the edges of the existing wound, so they usually look like a raised pink or red lump. Hypertrophic scars generally form within 4 to 8 weeks after an injury or wound has closed.
Keloid scars are essentially ‘aggressive’ hypertrophic scars that grow outside the edges of the existing wound. Keloid scars are all hypertrophic, meaning they are the result of excessive collagen formation, but not every hypertrophic scar will grow beyond the borders of the wound and become a keloid scar. Keloid scars can be experienced by anyone, but they most commonly occur with individuals that have darker skin.
Both hypertrophic and keloid scars can be caused by surgical incisions, injuries, acne, and even body piercings. Because hypertrophic or keloid scars are caused by excess collagen, they are virtually harmless. They are not cancer, but they can result in feelings of self-consciousness, especially if they are on the face or other areas that are not covered by clothing. In addition, they can be painful, itch, and remain sensitive to touch.
While the specific reasons silicone or glycerin gel sheeting is effective for preventing or reducing scars is still not clear, various theories about their use exist. These theories focus on temperature, pressure, oxygen, hydration, and the silicone or glycerin itself. Some of the data has been inconsistent. For example, studies have shown an increase in both temperature and pressure around a wound or scar under a gel sheet, others show no appreciable increase in either temperature or pressure, and others show an increase in temperature, but no increase in pressure, or vice versa. Silicone and glycerin sheets are gas permeable so oxygen can reach the skin and improve wound healing, but many other scar treatments allow oxygen to pass to the skin. The gel sheet may hold moisture in the skin longer, and prolonged hydration is thought to be the potential reason scars are prevented or reduced.
Finally, perhaps the silicone or glycerin itself stimulates increased cellular activity, or is used at the molecular level to speed healing. Whatever the specific reason(s) for the effectiveness of silicone or gel sheets on scars, it has been demonstrated that gel sheets are more effective than silicone or glycerin gel or oil alone, which leads many to believe the results of gel sheets are some combination of some or all of the factors outlined above.
Despite not having a clear understanding of the specifics, the effectiveness of silicone or glycerin sheets at preventing and reducing hypertrophic and keloid scars is supported by a number of clinical studies, and more controlled clinical studies have been performed on the treatment of scars using silicone or glycerin gel sheets than almost any other treatment.