Calluses form when the outer skin layer thickens in response to repeated friction or pressure, often under the forefoot or heel. In many people they act as a protective adaptation, but they can also become painful, cracked, or thick enough to change how weight is distributed through the foot.

That matters because discomfort can subtly alter gait and load patterns, which may worsen irritation or contribute to forefoot pain over time. The practical question is not whether callus “should” exist, but when it has crossed the line into something that needs controlled thinning—and how to do that without damaging healthy tissue.

Evidence consistently places professional mechanical removal at the top for immediate change. In a three-armed randomized comparative trial of plantar callus, scalpel debridement performed by podiatry produced immediate, significant improvements in objective skin measures (hydration, elasticity, texture, and size) and also improved associated foot pain and function (p < 0.01). Two home treatments—40% potassium hydroxide (KOH) and trichloroacetic acid (TCA)—also produced changes, but they were generally smaller and slower over a 21-day follow-up.

Importantly, this trial used biophysical measurements rather than only appearance, which strengthens the claim that the skin’s physical properties changed, not just the surface look. Meanwhile, chemical “gels” and softeners are not all the same: their active ingredients and concentrations determine both effect and risk.

A small pilot human-use study examined a commercially available callus softener containing <10% KOH, applied for 3–5 minutes before mechanical filing with a rasp. In 10 participants, no irritation, adverse reactions, or chemical burns were reported at immediate, 1-day, or 1-week checks, and callus severity scores generally improved from baseline (with some rebound by week 1).

This is encouraging for short-contact, label-directed KOH use, but the sample size was small and the intervention combined chemical softening with rasping, so the product’s standalone contribution cannot be fully separated. Evidence from dermatology also supports keratolytics more broadly: a randomized, double-blind, vehicle-controlled intra-individual study in adults with localized hyperkeratosis found greater short-term improvements on the treated side (notably for hyperkeratosis, desquamation, and dryness by day 10), with good overall tolerance reported—suggesting that keratolytic strategies can measurably improve thickened skin in certain conditions.

When comparing “gel” removers to regular callus removers, the most defensible distinction is mechanism. Mechanical options (pumice, files, rasps, and professional scalpel debridement) physically reduce thickness, and professional care delivers the fastest change with the most control in skilled hands. Chemical removers (KOH, TCA, and commonly salicylic-acid products) break down keratin and can make thick skin easier to remove or reduce gradually, but they carry a clearer edge-case danger: healthy skin can be over-treated.

Clinical guidance warns against self-trimming with sharp tools due to infection risk, and it highlights that medicated pads or liquids can irritate normal skin—especially in people with diabetes or poor circulation. In practice, gels can work, but the evidence suggests they are best viewed as adjuncts that require careful timing, targeted application, and attention to contraindications, rather than a universal “better” alternative to controlled mechanical thinning and pressure management.