1. Chung and associates, from the famed Beth Israel hospital in Boston, did a propsective double-blinded study, comparing the effects of the onion extract versus petrolatum gel (vaseline) on fresh surgical incisions. Each product was applied three times daily for 8 weeks. Results were rated at 2, 8, 12 weeks by non-biased evaluators for cosmetic appearance, redness and thickness. Result: no significant difference.
2. Jackson and Shelton, from MD Anderson Cancer Center in Houston, looked at surgical scars resulting from skin cancer removal with the Moh’s technique. Again, an ointment was applied three times daily for one month, and the results were compared. They found no benefit in the pre-treatment versus post-treatment levels of scar redness or itchiness with the onion extract, and actually found that the petrolatum group had less redness.
3. In an animal model, wound-healing guru and plastic surgeon Tom Mustoe and associates looked at the effect of Mederma on hypertrophic scarring. They found no significant reduction in scar redness, scar elevation or scar volume. They did see some changes in collagen organization when the scar tissue was examined under the microscope.
1. A study by Draelos examined the effect of Mederma on the appearance of surgical scars from the removal of skin lesions using the superficial shave technique, versus no additional treatment. She found that the Mederma treatment was statistically better than no treatment, improving scar softness, redness, texture and overall appearance.
2. Another study compared the effectiveness of onion extract versus silicone sheeting or silicone sheeting together with onion extract on hypertrophic and keloid scars. After 6 months of treatment, they found the combination treatment worked the best. The onion extract by itself seemed to improve scar color, but did not change scar height or itching of the scar.
Using Mederma is certainly better than doing nothing for your scar. It’s inexpensive, widely available, and well tolerated. It encourages people to do scar massage – which is also helpful to help scars become softer and more pliable.
However, I think there are other more scientifically-convincing products available for scar therapy. I usually recommend one of the many forms of topical silicone products for my patients, in addition to scar massage, sun avoidance, and if needed, IPL or kenalog treatments.