I've heard both good and bad things about Mederma.
They claim to be the most recommended product (by doctors and pharmacists) for scar removal but my dermatologist said that there's no scientific study that supports them and that dermatologists usually don't recommend them.
From what I found they may have some benfit on the appearance of scars. But the info available is contradictory.
It is featured in a article on ncbi.nlh.nih.org called: Snake oil for the 21st century
Effect of Mederma on hypertrophic scarring in the rabbit ear model
Improvement in dermal organization of collagen
No significant difference in dermal vascularity or inflammation
Computer analysis of the scar photographs demonstrated no significant reduction in scar erythema with Mederma treatment
A New Proprietary Onion Extract Gel Improves the Appearance of New Scars
once-daily application of the proprietary advanced formulation of onion extract gel is safe for use on new scars and significantly improves their overall appearance, redness, softness, and smoothness compared to control scars.
Hypertrophic Scarring and Keloids: Pathomechanisms and Current and Emerging Treatment Strategies
Two randomised studies by Draelos in 2008 (n = 60) and 2012 (n = 44), following shave excision of seborrheic keratoses, concluded that Mederma® improved the appearance, signs and symptoms of the healed wounds compared with untreated controls [42, 43]; however, both these studies note that funding was provided by the manufacturer Merz Pharmaceuticals.
As for the Amazon product I cannot find where it was sponsored or approved for safety.
