We're not sure which dermatologist would legitimately consider this a "solution" for skin, at least if they're somewhat familiar with skincare formularies and their impact on skin. Dermatologist Solutions Nightly Refining Micro-Peel Concentrate lists denatured alcohol as its second ingredient, which is a skincare no-no if your goal is treating skin gently (and that should be everyone's goal, because "gentle" is the operative word for better skin plus helping restore skin and fight aging!). See More Info to learn why using alcohol-based skincare products is a bad idea.
Another concerning ingredient is hydroxyethylpiperazine ethane sulfonic acid (also known as HEPES). It's a buffering ingredient (typically used to establish a neutral pH) with research indicating it can generate free radical damage in the presence of oxygen (Journal of Inorganic Biochemistry, November 2004, issue 11, pages 1696-1702). That has us worried even though research on how this directly impacts skin hasn't been done. Still, there are definitely other buffering agents that could have been used instead of this ill-chosen one.
Between the alcohol and the HEPES, there is enough reason for us to stop writing and for you to look for other peel options but just to finish our job, this fluid solution contains hydroxyethyl urea, an ingredient that can exfoliate skin which Kiehl's describes as "accelerate surface skin cell turnover".
There's research showing urea as an exfoliant works best in amounts of 5% or greater (Dermatologic Therapy, March 2015). Kiehl's might be using that amount, but we can't be certain, and the company wouldn't reveal the amount of urea the product contains.
Urea does have hydrating properties for skin, and the dropper dispenser makes the amount you apply easy to control, but there's just too many significant problems including several citrus extracts which can convey antioxidant benefits but they also pose a risk of sensitizing skin—not what's needed in any product, let alone one that contains so much alcohol and potentially problematic HEPES!
There are reasons to consider using at-home peel products, particularly if you have uneven, sun-damaged skin, but this contribution from Kiehl's is a serious misfire. See our list of Best Exfoliants for superior options.
Alcohol-Based Skincare Products: Alcohol's effect on your skin is similar to its effect on the rest of your body: it steals the good (hydration) and leaves the bad (dryness, redness, and discomfort). Research has made it clear that alcohol as a main ingredient in any skincare product you use repeatedly is a problem.
When we express concern about the presence of alcohol in skincare or makeup products, we're referring to denatured ethanol, which you'll most often see listed as SD alcohol, alcohol denat, denatured alcohol, or isopropyl alcohol on the ingredient label.
When you see these names of this type of alcohol listed among the first six ingredients on an ingredient label, without question they will aggravate and be cruel to skin. No way around that, it's simply bad for all skin types.
These types of volatile alcohols give products a quick-drying finish, immediately degrease skin, and feel weightless, so it's easy to see their appeal, especially for those with oily skin. But those short term benefits lead to negative long term outcomes!
Consequences include dryness, erosion of skin's surface (that's really bad for skin), and a strain on how skin replenishes, renews, and rejuvenates itself. Alcohol just weakens everything about skin.
We are often challenged on this information based on a study in the British Journal of Dermatology, July 2007, issue 1, pages 74-81 that concluded "alcohol-based hand rubs cause less irritation than hand washing…" The only thing this study showed is that alcohol was not as irritating as an even more irritating hand wash containing sodium lauryl sulfate. Think about it this way, if you test to see whether or not you'll get burnt by a flame or slowly boiling hot water, you will quickly get damaged by the fire. You will eventually be damaged by the slowly boiling hot water, it will just take longer, but burned you will be.
There are other types of "alcohols", known as fatty alcohols, which are absolutely non-irritating and can be exceptionally beneficial for skin. Examples you'll see on ingredient labels include cetyl, stearyl, and cetearyl alcohol. All of these are good ingredients for skin. It's important to discern these skin-friendly forms of alcohol from the problematic types of alcohol.
The irony of using alcohol-based products to control oily skin is that the damage from alcohol can lead to an increase in bumps and enlarged pores. Alcohol can actually increase oiliness because of the irritating feeling it creates, so the immediate de-greasing effect is eventually counteracted, prompting your oily skin to look even shinier.
References for this information:
Dermato-Endocrinology, January 2011, issue 1, pages 41-49
Experimental Dermatology, June 2008, issue 6, pages 542-551
Alcohol Journal, April 2002, issue 3, pages 179-190
Aging, March 2012, issue 3, pages 166-175
Chemical Immunology and Allergy, March 2012, pages 77-80
Journal of Occupational Medicine and Toxicology, November 2008, issue 3
Clinical Dermatology, September-October 2004, issue 5, pages 360-366.