Benzoyl peroxide: Gets into the skin and does its thing amazingly well. 2.5% works better than 5% or 10% because it is less irritating but still creates plenty of oxygen to kill the bacteria. Used precisely within The Regimen it predictably clears up the skin completely within 3-4 months.
Salicylic acid: Doesn't seem to do anything at 2% strength, which is the legal limit in OTC products. I tried upwards of 15 salicylic acid products since I was a teenager and I would say they are a waste of money.
Tea tree oil: I have tried tea tree oil in many different strengths, and in several "natural" acne products. In my personal experience, it does nothing. While I love the idea of a "natural" acne remedy, tea tree oil most definitely wasn't it for me.
The clear winner: Benzoyl peroxide. It's not even a contest honestly. Benzoyl peroxide works, and the other two do not.
Pretty sure it's legal to sell up to 20% salicylic acid peels over the counter.
Otherwise Skin Laboratories, Makeup Artists' Choice, Perfect Image, and Diana Yvonne would have all been shut down a LONG time ago. Perfect Image actually got a FDA recall just a few months ago on their hair loss product because it contained too high minoxidil, so they were just investigated and didn't have to stop selling their at-home peels.
For some of us, higher strength salicylic acid makes a difference in clogged pores that benzoyl peroxide does not.
Most cases of acne vulgaris are either mild or moderate in severity and well-suited for treatment with nonprescription agents that are safe, effective, and convenient to use. A review of four clinical studies and a comedolytic assay attests to the efficacy and safety of 0.5% and 2% solutions of salicylic acid for the treatment of acne vulgaris. In three placebo-controlled studies and a comedolytic assay, salicylic acid pads reduced the number of primary lesions and thereby the number and severity of all lesions associated with acne. Comparative studies of salicylic acid have shown it to be superior to benzoyl peroxide in reducing the total number of acne lesions. Adverse reactions to salicylic acid are generally limited to mild, local irritation occurring in a minority of patients.
Eighty subjects with mild to moderate facial acne were randomized to receive either the LHA formulation twice a day or benzoyl peroxide once a day for 12 weeks. Efficacy and tolerance were evaluated at days 0, 28, 56 and 87. Results LHA formulation and benzoyl peroxide decreased the number of inflammatory lesions from baseline to week 12 by 44% and 47% and noninflammatory lesions by 19% and 23%, respectively. There was no statistically significant difference between the two treatments (P = 0.748; P = 0.445).
A 12-week double-blind randomized study was performed to compare benzoyl peroxide 5% (BP) gel and chloroxylenol 0.5% plus salicylic acid 2% (PCMX + SA) cream (Nisal cream) for efficacy and adverse reactions. Thirty-seven volunteers participated in the study, 19 in the BP group and 18 in the PCMX + SA group. The patients applied the medication twice daily to the entire face. Clinical evaluation and lesion counts were obtained at 0, 3, 6, 9 and 12 weeks. At week 12 both groups showed a marked improvement in both inflammatory and noninflammatory lesions (60% and 54% for the BP group and 62% and 56% for and 56% for the PCMX + SA group, respectively). Although PCMX + SA showed a slightly stronger keratolytic effect throughout the study period, there was no statistically significant difference in the reduction of the papulopustules or comedones between the two groups. Adverse effects such as erythema and photosensitivity were significantly fewer in the PCMX + SA group at week 12 (p = 0.0002 and p = 0.05, respectively). These results suggest that PCMX + SA cream is as effective as BP gel in the treatment of papulopustular and comedonal acne and that it is better tolerated.
after 3 h, bp was significantly more effective in disrupting sc cohesion than sa and ra, indicating bp is a moderate keratolytic agent in addition to its antimicrobial properties. After 6 h, all three agents were similarly effective in keratolysis. Barrier disruption, as measured by TEWL, paralleled depth of SC removal. SA tended to exhibit the greatest keratolytic efficacy superficially, hence its clinical effectiveness in superficial conditions such as comedonal acne, whereas BP was more effective at deeper levels, complimenting its antimicrobial effects and enabling it to treat deeper, more inflammatory lesions. None of the agents significantly affected skin erythema. These techniques provide a robust and rapid assay for in vivo keratolytic demonstration.
I think it's a stretch to say that salicylic acid "does not work."
I actually personally agree most with the study that stated benzoyl peroxide is better for inflammatory lesions, and salicylic acid is way better for comedones.
Certainly drugstore salicylic acid is ineffective. It's pH is usually too high and it has too many filler ingredients to penetrate into the skin. If you get a quality product at a 2.0 pH or lower that is almost purely salicylic acid, there is a HUGE difference in efficacy.
Edited by Green Gables, 21 September 2012 - 08:51 PM.