Baby Foot is an exfoliating foot peel – you put your feet into two gel-soaked plastic socks for an hour, wash it off, then over the next week or so, flakes of skin come off and you’re left with… “baby feet”. There are dozens of imitations on the market now from brands like Tony Moly, Etude House, Treat My Feet, The Face Shop and Shara Shara, which is what I’ve used the most recently. They all have the same active ingredient and work the same way, though depending on the amount of active ingredient and the formula, some work better than others.
Baby Foot Ingredients
Here are the ingredients for Baby Foot:
Water, Alcohol, Lactic Acid, Glycolic Acid, Arginine, Butylene Glycol, PEG-60 Hydrogenated Castor Oil, Glucose, O-Cymen-5-ol, Citric Acid, Malic Acid, Citrus Aurantium Dulcis (Orange) Oil, Citrus Grandis (Grapefruit) Peel Oil, Dipotassium Glycyrrhizate, Cymbopogon Schoenanthus Oil, Nasturtium Officinale Extract, Arctium Lappa Root Extract, Saponaria Officinalis Leaf Extract, Hedera Helix (Ivy) Extract, Salvia Officinalis (Sage) Leaf Extract, Citrus Medica Limonum (Lemon) Fruit Extract, Clematis Vitalba Leaf Extract, Spiraea Ulmaria Flower Extract, Equisetum Arvense Extract, Fucus Vesiculosus Extract, Chamomilla Recutita (Matricaria) Flower Extract, Camellia Sinensis Leaf Extract, Houttuynia Cordata Extract, Phenoxyethanol, Hydroxyethylcellulose, Salicylic Acid
And the ingredients for Shara Shara Smooth Bebe Foot:
The key active ingredients are lactic acid and glycolic acid, which are alpha-hydroxy acids or AHAs.
Alpha hydroxy acids are chemical exfoliants which consist of an OH hydroxy group (the red part) two bonds away from a carboxylic acid (the blue part). Exfoliation can be physical or chemical – physical exfoliation involves mechanically buffing away the surface layers of the skin (the stratum corneum). Chemical exfoliants like alpha hydroxy acids and beta hydroxy acids penetrate into the stratum corneum and break it up into smaller sections – this would naturally happen as the cells rise to the surface, but chemical exfoliants speed up this process. (For the difference between AHAs and BHAs, check out this post.)
At the moment, it’s not entirely clear how AHAs cause the dead skin layers to break down. It was originally thought that they break down the junctions or “glue” (desmosomes) holding the dead skin cell “bricks” (corneocytes) together, but the best contender for the mechanism so far is that AHAs trigger an influx of calcium into the corneocytes themselves, which burst, causing exfoliation.
Formulation Aspects for Foot Peels
For the AHAs to reach the lower layers of the stratum corneum, they have to penetrate into the skin, which is difficult because skin is a fantastic barrier against most chemicals, and foot skin is particularly tough. Two things help the AHAs penetrate: low pH (high acidity) and penetration enhancers.
Uncharged chemicals penetrate membranes better, and low pH causes AHAs to remain neutral (the science behine pH and AHAs is a little complex but it’s here if you’re interested). Penetration enhancers usually disrupt the skin barrier and make it easier for chemicals to penetrate – alcohol is a good penetration enhancer, so it’s generally the first or second ingredient in these foot peels. I know “disrupting the skin barrier” sounds pretty bad, but it’s necessary for tough foot skin, and it reverses reasonably quickly with alcohol when compared to the surfactants you’d find in most cleansers. Alcohol’s bad rap in general isn’t well deserved – there’s a breakdown of the myths surrounding alcohol in skincare on Futurederm here.
Why Do Foot Peels Have a Lag Time?
If you’ve tried a foot peel, you’ll know that it takes a few days or even a week before the peeling actually happens (and when it does, it’s a little frightening how much skin there is). That’s the way that chemical exfoliation works – it takes a little while for the dead layers to break down enough to detach from the layers underneath, unlike the instant gratification you get from physical exfoliation. (I have some photos of my peely feet if you’re really curious – it’s gross. Click at your own risk.)
X Cao, F Yang, J Zheng and KW Wang, Intracellular Proton-mediated Activation of TRPV3 Channels Accounts for the Exfoliation Effect of α-Hydroxyl Acids on Keratinocytes (open access), J Biol Chem, 2012, 287, 25905-25916.
H Löffler, G Kampf, D Schmermund and HI Maibach, How irritant is alcohol? British Journal of Dermatology, 2007, 157, 74–81.
This post contains affiliate links – please click through if you’d like to support Lab Muffin financially (thank you!). For more information, see Disclosure Policy.