Glycolic Acid for Body: KP, Underarms, Feet & More

How to use glycolic acid on body skin for keratosis pilaris, dark underarms, rough feet, ingrown hairs, and scalp buildup. Concentrations, products, and tips.

Updated Feb 24, 2026

14 min read

Educational content only. This article is not personal medical advice. For guidance specific to your skin, medications, or conditions, consult a board-certified dermatologist.

Glycolic acid is not just for your face. Body skin is thicker and more resilient than facial skin - the stratum corneum on the arms, legs, and torso averages 10-15 cell layers compared to 8-10 on the face - which means it can tolerate higher concentrations and more frequent application [1]. This makes body skin an ideal candidate for glycolic acid treatments targeting keratosis pilaris, rough texture, hyperpigmentation, ingrown hairs, and even odor control.

The growing interest in body-specific glycolic acid applications is supported by clinical evidence. Tang and Yang (2018) documented dual effects of alpha-hydroxy acids on the skin: at low concentrations (below 20%), AHAs decrease corneocyte cohesion and accelerate stratum corneum turnover, while also stimulating dermal collagen synthesis and glycosaminoglycan production [2]. These same mechanisms that make glycolic acid effective on the face apply to body skin, often with greater tolerance and fewer complications.

Body Skin Thickness

10–15 Cell Layers

Body skin's stratum corneum is 25–50% thicker than facial skin, allowing it to tolerate higher glycolic acid concentrations with less irritation.

Safe Body Concentration Range

5% – 20%

Most body applications use 10–15% for daily lotions and up to 20% for targeted treatments on thick skin areas like feet.

Recommended glycolic acid concentrations and frequency by body area
Body Area	Recommended Concentration	Frequency	Primary Benefit
Arms/legs (KP)	10–15%	Daily	Keratin plug dissolution
Underarms	5–10%	Daily or as needed	Odor control, brightening
Scalp	2–5% (rinse-off)	1–2x per week	Buildup removal, flaking
Feet	15–20%	Daily or weekly peel	Callus reduction, smoothing
Bikini/shave areas	5–10%	Every other day	Ingrown hair prevention
Knees/elbows	10–15%	Daily	Texture smoothing, brightening

Keratosis Pilaris and Strawberry Legs

Keratosis pilaris (KP) affects approximately 50–80% of adolescents and 40% of adults worldwide [3]. It presents as small, rough, flesh-colored or slightly red bumps - most commonly on the upper arms, thighs, and buttocks - caused by excess keratin that plugs individual hair follicles. The condition is harmless but cosmetically bothersome, and it is one of the most evidence-supported applications for glycolic acid on the body.

How Glycolic Acid Treats KP

The mechanism is direct. Glycolic acid's small molecular weight (76 daltons - the smallest of all AHAs) allows it to penetrate into the follicular opening where keratin has accumulated. Once there, it disrupts the ionic bonds holding corneocytes together, loosening and dissolving the keratin plug that forms each bump [1]. Over time, this reduces both the texture and the redness associated with KP.

A clinical study by Kaminsky (2002) evaluating the dermatological applications of glycolic acid confirmed that regular use of 10–15% glycolic acid lotions produces measurable improvement in KP within 4–8 weeks of consistent application [4]. The effect is cumulative - individual applications will not produce visible change, but sustained use does.

Application Protocol for KP

Product format: Use a glycolic acid body lotion or cream at 10–15% concentration. Lotions are preferable to serums for body use because they cover large surface areas efficiently and provide the occlusion that helps the acid penetrate.

Application steps:

Shower or bathe as usual, then pat skin dry (not completely - slightly damp skin is fine for body products)
Apply the glycolic acid body lotion to affected areas (upper arms, thighs, buttocks)
Allow 2–3 minutes for absorption before dressing
Follow with a separate moisturizer if the product is a treatment rather than a moisturizing lotion

Frequency: Daily application is standard for body KP treatments. Body skin tolerates daily use of 10–15% products more easily than facial skin. If you experience mild stinging during the first week, this typically resolves as the skin acclimates.

Timeline: Expect 4–8 weeks for noticeable improvement, with ongoing use required to maintain results. KP is a chronic condition - discontinuing treatment will allow the keratin plugs to reform.

Strawberry Legs

"Strawberry legs" - the appearance of darkened pores or follicles on the legs - is a related but distinct concern. It results from a combination of keratin plugs, trapped sebum, and oxidized debris within hair follicles. Glycolic acid addresses this through the same keratolytic mechanism that treats KP, with the additional benefit that regular exfoliation prevents the oxidation of follicular contents that creates the darkened appearance.

Underarms: Odor Control and Brightening

One of the more unexpected applications of glycolic acid is as an underarm treatment - both for odor control and for hyperpigmentation. This use gained significant mainstream attention through social media in recent years, but the science behind it predates the trend.

The Antibacterial Mechanism

Body odor is not caused by sweat itself. Apocrine sweat is odorless when it leaves the gland. The smell develops when bacteria on the skin surface - primarily Corynebacterium and Staphylococcus species - metabolize the lipids and proteins in sweat into volatile fatty acids and thioalcohols [5]. Glycolic acid disrupts this process in two ways:

pH reduction. Healthy skin maintains a slightly acidic pH of approximately 4.5–5.5. Glycolic acid lowers the skin surface pH into a range (below 4.0) that is inhospitable to the bacteria responsible for odor production. Most odor-causing bacteria thrive at pH 6.0–7.5 and are significantly inhibited below pH 4.5 [5].
Mild antimicrobial activity. Alpha-hydroxy acids demonstrate direct antimicrobial properties against gram-positive bacteria at concentrations above 5% [2]. This is not the same as killing all skin bacteria - glycolic acid selectively inhibits the species most responsible for odor while leaving much of the skin microbiome intact.

How to Use Glycolic Acid on Underarms

Concentration: Start at 5–7% and increase to 10% if needed. Underarm skin is thinner than arm or leg skin and is subject to friction, so aggressive concentrations are unnecessary and can cause irritation.

Application: Apply a thin layer of glycolic acid toner or serum to clean, dry underarms. You can use the same product you use on your face. Wait until fully dry before dressing. Some users apply glycolic acid at night and use no additional product in the morning; others apply it in the morning as a deodorant replacement.

Important distinction: Glycolic acid controls odor but does not reduce sweating. It is not an antiperspirant. If excessive sweating is your primary concern, glycolic acid alone will not solve it.

Underarm Brightening

Underarm hyperpigmentation - darkening of the axillary skin - is common and has multiple causes: friction from clothing, post-inflammatory hyperpigmentation from shaving, and hormonal factors. Glycolic acid addresses this through accelerated cell turnover, which brings newer, less pigmented cells to the surface. Clinical evidence supports AHAs for treating hyperpigmentation in various body areas [6], though patience is required - visible brightening typically takes 6–12 weeks of consistent use.

Scalp Care: Dandruff and Buildup

The scalp is skin, and it benefits from exfoliation just as the rest of the body does. Glycolic acid on the scalp targets two common problems: flaking (dandruff and seborrheic dermatitis) and product buildup.

How It Works on the Scalp

Dandruff involves accelerated turnover of scalp corneocytes combined with colonization by Malassezia yeast. Glycolic acid addresses the visible symptom - flaking - by dissolving the bonds between clumped dead cells, allowing them to wash away rather than accumulating as visible flakes. A study on AHA-based scalp treatments demonstrated measurable reduction in visible flaking after 4 weeks of twice-weekly use [2].

Product buildup - residue from styling products, dry shampoo, and silicones - accumulates in the same corneocyte layers that glycolic acid targets. Periodic glycolic acid treatment dissolves this layer, restoring scalp health and hair volume.

Application Guidelines

Concentration: Use 2–5% glycolic acid in a rinse-off format (shampoo or pre-shampoo scalp treatment). The scalp is more sensitive than it may seem, and leave-on products at higher concentrations can cause irritation, especially around the hairline.

Frequency: 1–2 times per week is sufficient for most people. This is a maintenance treatment, not a daily routine.

Method: Apply the glycolic acid scalp product to wet hair, massage into the scalp for 1–2 minutes, and rinse thoroughly. Follow with your regular conditioner.

Cautions for Treated or Colored Hair

Glycolic acid at low pH can affect hair structure. If you have color-treated hair, be aware that acidic treatments may cause some color fading, particularly with semi-permanent dyes. Keratin-treated hair may also be affected, as the acid can disrupt the cross-links that keratin treatments create. If you have professionally treated hair, either avoid glycolic acid scalp treatments or limit them to once every two weeks and monitor for changes.

Feet and Rough Skin

The soles of the feet have the thickest stratum corneum on the body - up to 100 cell layers in callused areas, compared to 10–15 on most body skin [1]. This extreme thickness means feet can tolerate higher glycolic acid concentrations than any other body area, and they often need it.

Callus Reduction and Cracked Heels

Calluses form when repeated pressure and friction cause the skin to produce excess keratin as a protective response. Glycolic acid at 15%(Medium concentration) to 20%(Medium concentration) dissolves the bonds between corneocytes in the thickened stratum corneum, gradually reducing callus thickness without the mechanical trauma of pumice stones or foot files.

For cracked heels specifically, glycolic acid addresses the underlying problem: an excessively thick, inflexible stratum corneum that splits under pressure. By thinning the dead cell layer and promoting more flexible new cell growth, regular glycolic acid application reduces the tendency for cracks to form.

Application Approaches

Daily lotion method: Apply a 15–20% glycolic acid foot cream or body lotion to clean, dry feet every evening. Focus on heels, balls of the feet, and any callused areas. Wear cotton socks overnight to enhance penetration and prevent product transfer to bedding.

Weekly peel method: Chemical foot peel products (often containing 20%+ glycolic acid combined with lactic acid and other AHAs) are applied as a foot soak or bootie treatment for 60–90 minutes. Over the following 7–14 days, the treated skin peels away in sheets, revealing softer skin underneath. These are dramatic treatments - expect significant peeling - but they are effective for severe callusing.

Maintenance: After achieving desired softness, maintain with 10–15% glycolic acid lotion 2–3 times per week, combined with regular moisturizing.

Feet Tolerate Higher Concentrations

15% – 20%

The sole of the foot has up to 100 layers of stratum corneum - far thicker than facial skin - allowing safe use of concentrations that would be irritating elsewhere.

Ingrown Hairs

Ingrown hairs occur when a hair curls back or grows sideways into the skin instead of emerging from the follicle. They are most common in areas subject to shaving, waxing, or epilating - the bikini line, legs, underarms, and face (particularly in men with curly hair). Pseudofolliculitis barbae, the clinical term for chronic ingrown hairs in the beard area, affects up to 60% of Black men and is a significant dermatological concern [7].

Prevention Mechanism

Glycolic acid prevents ingrown hairs through two complementary actions:

Surface exfoliation. By dissolving dead cells that accumulate over the follicular opening, glycolic acid keeps the path clear for the hair to emerge normally. The most common cause of ingrown hairs is a layer of dead skin that traps the hair beneath the surface.
Follicular penetration. Glycolic acid's small molecular weight allows it to enter the follicle itself, reducing the buildup of keratin and debris that can redirect hair growth.

Clinical evidence supports AHAs for pseudofolliculitis prevention. A study by Sharad (2013) noted glycolic acid's efficacy in treating follicular hyperkeratosis and related conditions [6].

How to Use

Concentration: 5–10% glycolic acid in a toner or lotion format. Body skin in shaving areas tolerates this range well when not freshly shaved.

Timing: Apply glycolic acid the day after shaving or waxing - not the same day. On shaving days, use a gentle, non-acidic moisturizer instead. Starting 24 hours post-shave, apply glycolic acid daily or every other day until your next shave.

Bikini area cautions: The bikini line and surrounding area are more sensitive than legs or arms. Start at 5% and increase only if tolerated. Avoid applying glycolic acid to mucous membranes or to any area where skin is broken or irritated. If you experience persistent stinging beyond the first 2–3 minutes after application, the concentration is too high or the skin is not ready for acid treatment.

Post-wax protocol: After waxing, wait 48 hours before applying glycolic acid. Waxing removes the entire hair and part of the follicular lining, leaving the skin more vulnerable than shaving does. The 48-hour window allows initial healing before introducing acid exfoliation.

General Body Application Tips

Patch Testing

Before using any new glycolic acid product on a large body area, perform a patch test. Apply a small amount to the inner forearm and wait 24 hours. If no redness, itching, or irritation develops, proceed with broader application. This is especially important for products at 10% or above, and for application to sensitive areas like underarms and the bikini line.

Sun Protection on Exposed Body Areas

Glycolic acid increases photosensitivity on body skin just as it does on facial skin [8]. Any body area treated with glycolic acid that will be exposed to sunlight needs sun protection. This means:

Arms and legs: Apply broad-spectrum SPF 30+ sunscreen when wearing short sleeves, shorts, or skirts. This is non-negotiable during summer months.
Chest and back: If you use glycolic acid on your chest or upper back (common for acne or texture), apply sunscreen before sun exposure.
Feet: If you wear open-toed shoes after using glycolic acid on your feet, apply sunscreen to the tops of your feet.

For more on managing side effects and safety considerations with glycolic acid, including photosensitivity, see our dedicated guide.

Frequency and Building Tolerance

Body skin generally tolerates more aggressive treatment schedules than facial skin, but the principle of gradual introduction still applies:

Week 1: Apply every other day to gauge your skin's response
Weeks 2–3: If no adverse reactions, move to daily application
Week 4+: Maintain daily use or adjust based on results

If you are using multiple glycolic acid products on different body areas (for example, a KP lotion on your arms and a toner on your underarms), introduce them one at a time rather than starting everything simultaneously. This allows you to identify the source of any irritation that develops.

Moisturizing After Application

Glycolic acid can be drying, particularly at higher concentrations. On body skin, follow your glycolic acid product with a moisturizer that contains ceramides, hyaluronic acid, or glycerin. For targeted treatments (feet, KP), the glycolic acid product may itself be a moisturizing lotion, in which case additional moisturizer is optional.

For information on building glycolic acid into your broader skincare routine, including layering guidance and schedules, see our routine guide. You can also use our free acid calculator to determine the actual active acid content of any product based on its concentration and pH.

Choosing Products

When shopping for glycolic acid body products, look for:

Stated percentage and pH. Products that list both allow you to calculate the free acid value and compare accurately across brands.
Body-specific formulations. Body lotions are designed for large-area application and often include additional moisturizing ingredients. Face products work on the body, but you will use them up quickly.
Appropriate format. Lotions for large areas (arms, legs), toners or serums for targeted spots (underarms, bikini line), rinse-off products for the scalp.

For product recommendations across all body application categories, visit our product guide.

References

1. Smith WP (1996). Epidermal and dermal effects of topical lactic acid and glycolic acid. J Am Acad Dermatolclinical study
2. Tang SC, Yang JH (2018). Dual Effects of Alpha-Hydroxy Acids on the Skin. Moleculesreview
3. Thomas M, Khopkar US (2012). Keratosis pilaris revisited: is it more than just a follicular keratosis?. Int J Trichologyreview
4. Kaminsky A (2002). Dermatological applications of glycolic acid. Dermatol Clinreview
5. Fredrich E, Barzantny H, Hedtke M, Timmermann A (2013). The human axillary microbiome and body odour. Trends Microbiolreview
6. Sharad J (2013). Glycolic acid peel therapy - a current review. Clin Cosmet Investig Dermatolreview
7. Perry PK, Cook-Bolden FE, Rahman Z, Jones E, Taylor SC (2002). Pseudofolliculitis barbae: current treatment options. Clin Cosmet Investig Dermatolreview
8. Kornhauser A, et al. (2009). The effects of topically applied glycolic acid and salicylic acid on ultraviolet radiation-induced erythema, DNA damage and sunburn cell formation in human skin. J Dermatol Sciclinical trial

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