Roll-on vs. Bottled
The product inside the roll-on and larger bottles are the same. Which is better, depends largely on how it is applied, and the desired area of application. The 10ml roll-on was designed for touching up problem spots or for applying the peel to specific areas. However, if you are looking for a full facial treatment, I would recommend the 30ml bottle, or possibly one of each.
By having one of each, you can both spot-treat, and perform full facials. When applying to the entire surface of the face, it is easiest to use a cotton ball or pad, a gauze pad, or a fan brush. The Roll-on applicator tip will apply a thinner coat than what could be applied using the other methods.
Because the depth of a peel is controlled by a couple of factors, and application thickness is one of them, most prefer to use a cotton ball, or gauze pad. Using a fan brush can be a bit tricky at first, but once you are used to it, it is rather simple. It is not impossible to use a Roll-On applicator for a full facial treatment.
The feedback we have received is that using the Roll-On for a full facial treatment took too long. By the time the peel was completely applied, it was already time for some to begin removing the peel.
Shelf Life and Storage
The product does not expire because of the low risk of bacterial contamination due to the high acid content, but as is good practice with all cosmetic products, it is best to use them within a year.
Differences in Salicylic, Lactic, and Glycolic
Lactic is best for treating age/sun spots and the pure Glycolic is best for treating fine lines. The Glyco/Lac combination is great if you are looking for a revitalizing improvement in tone and texture. The Lactic and Glycolic peels are very similar in their actions, but the molecules are slightly different. I have found that a good rule of thumb is the pure Lactic is best for treating age/sun spots and the pure Glycolic is best for treating fine lines. The Glyco/Lac combination is great if you are looking for a revitalizing improvement in tone and texture.
Glycolic vs. Salicylic
Comparing the Salicylic and Glycolic acids can be difficult, as the results each acid has on skin varies from individual to individual. However, Salicylic acid is a generally more effective exfoliant than Glycolic acid, and less harsh on the skin.
The reason for this is a small amount of the Salicylic acid is converted into copper salicylate which acts as an anti-inflammatory, allowing for a much higher tolerance. In one study comparing a 1.5 percent Salicylic acid product and an 8+ percent Glycolic acid product, the Salicylic acid product was shown to be a more effective exfoliant.