Strength is only one of the two numbers that matter. The other is pH, which decides how much of that concentration is actually active on the skin; the distinction is set out in the free acid value. And why a body needs a different intensity to the face is the subject of why the body is not a bigger face.

The Lotion Standard · Marker One in depth

The ladder that isn't: why a stronger acid is not a better body lotion

The Lotion Editorial Assessed against peer-reviewed dermatological literature Reading time 7 minutes

We are trained to read strength as a single line, where higher is always further along. With acids on the body, that line is a fiction. There is no one ladder, only different jobs done at different intensities.

In brief

A higher glycolic acid percentage does not make a better body lotion. A leave-on lotion and a professional peel are different jobs, not two rungs of one ladder: a peel uses a high concentration at low pH for brief, supervised, rinsed-off contact, while a daily lotion works at a moderate concentration left on the skin and used consistently over time. For a leave-on product, the measure that predicts results is tolerated, repeated exposure, not peak strength. Beyond the point the skin can comfortably sustain, more acid buys irritation rather than benefit.

Strength is the easiest thing to sell, because it is the easiest thing to compare. One number, larger than another, implying more for your money and faster results. It is also where most people choosing a body acid go wrong, because they are comparing numbers that belong to entirely different activities, as though a marathon and a sprint could be ranked on a single scale of speed.

The confusion comes from treating concentration as a ladder, where a stronger acid is simply a more advanced version of a weaker one. In reality there are different exposure models, and the right concentration depends entirely on which one you are in.

Two different jobs, mistaken for one ladder

A professional glycolic peel is a controlled, deliberate injury. It uses a high concentration at a low pH, applied for a short, carefully timed contact and then neutralised or rinsed away, under the supervision of a trained practitioner. The depth of the peel rises with the concentration, the number of coats and the contact time, which is exactly why it is timed and watched: unbuffered glycolic acid at high strength can cause blistering and scarring if left unmanaged.¹ That supervision is not a formality. It is the safety system that makes the high number reasonable.

A daily leave-on body lotion is the opposite proposition. It stays on the skin. It is not rinsed, not neutralised, not supervised, and it is used again tomorrow and the day after. Its job is not a single dramatic event but a steady, sustainable nudge toward smoother skin over weeks. A concentration that makes sense for a few rinsed-off minutes under supervision makes no sense at all for something you leave on your arms every night.

In-clinic peel

A controlled event

Strength: High, professional-grade
Contact: Brief, then neutralised or rinsed
Oversight: Trained practitioner
Frequency: Occasional, spaced out

At-home treatment

An occasional reset

Strength: Elevated, short wear
Contact: Minutes, then removed
Oversight: Self-directed, with care
Frequency: Periodic

Daily leave-on lotion

A sustained habit

Strength: Moderate, left on skin
Contact: Continuous, not rinsed
Oversight: None needed
Frequency: Regular, ongoing

Three different jobs. Reading them on one "higher is better" scale is the most common mistake in body acids.

The point of diminishing returns

Alpha hydroxy acids have what the literature describes as dual, concentration-dependent effects: at measured concentrations they encourage orderly renewal, while at excessive ones the same chemistry tips toward irritation and barrier disruption.² For a leave-on product, this matters enormously, because the benefit is not delivered in a single use. It accumulates across many. The most effective concentration is therefore not the highest the skin can briefly survive, but the one it can comfortably tolerate, night after night, without the redness or stinging that makes people abandon the routine altogether.

Push past that point and you do not get more renewal. You get a product too harsh to use consistently, which means less renewal, not more, because the bottle ends up at the back of the cupboard. Strength that cannot be sustained is not strength at all.

The acid that works is not the strongest one. It is the one you will still be using in three months.

The number that actually predicts results

For a daily lotion, results track tolerated, repeated exposure: a moderate concentration, formulated at a working pH and buffered with the humectants and lipids that keep skin comfortable, applied consistently over time. This is why a thoughtfully built moderate-strength lotion routinely outperforms a higher number formulated carelessly. One you will use; the other you will flinch from.

A brief practical note that the responsible literature insists upon: because glycolic acid can increase the skin's sensitivity to sunlight, daily sun protection on exposed areas belongs alongside any leave-on acid routine.³

The question to ask

Not "how strong is it?" but "can I use this every day without my skin protesting?" A leave-on body lotion earns its place through consistency, so the right strength is the one matched to daily, tolerated use, supported by a considered pH and a barrier-friendly base, not the largest number on the shelf.

This is the first of the markers in the six-marker clinical body lotion standard, read properly: a disclosed concentration is necessary, but it is only meaningful once you know the exposure model it belongs to. For more on how that number behaves once it is in a formula, it is worth understanding how acid strength is read on body skin. The Lotion's 12% glycolic acid body lotion is built as a leave-on product: a moderate, daily-tolerable strength, formulated within the working pH and partnered with urea, niacinamide and shea, rather than a peel-grade number repurposed into a bottle.

About

The Lotion

The Lotion is an Australian clinical body skincare house. Its focus is a single category: resurfacing body care built on disclosed actives and barrier science rather than fragrance and finish.

The hero formula is a 12% glycolic acid AHA body lotion with urea, niacinamide and shea butter, made in Australia, fragrance-free, vegan and cruelty-free. It is formulated against six verifiable markers: a named concentration, a working pH, barrier support, sensitiser restraint, a defined mechanism, and traceable Australian manufacture.

Questions readers ask

Is a higher percentage glycolic acid body lotion better?

Not for a leave-on product. A daily lotion delivers its benefit through repeated, tolerated use, so the most effective strength is the one you can comfortably apply consistently. A higher number you cannot sustain produces less renewal, not more, because the routine breaks down. Strength and tolerability have to be balanced.

What is the difference between an at-home acid and an in-clinic peel?

They are different jobs. A peel uses a high concentration at low pH for a brief, supervised, rinsed-off contact, where depth rises with concentration and time. A leave-on lotion uses a moderate concentration left on the skin and used regularly. A peel-grade strength is unsafe and unnecessary in a daily product.

What strength of glycolic acid is right for daily body use?

A moderate concentration that the skin tolerates without redness or stinging, formulated within the acid's working pH and buffered with humectants and lipids. The exact number matters less than whether it is sustainable day to day, because consistency over weeks is what produces visible change.

Does glycolic acid make skin sensitive to the sun?

Glycolic acid can increase the skin's sensitivity to sunlight, so daily sun protection on exposed areas is sensible alongside any leave-on acid routine. This is a standard precaution emphasised across the dermatological literature.

Why does a strong acid sometimes give worse results?

Because alpha hydroxy acids have concentration-dependent effects: measured strengths encourage orderly renewal, while excessive ones tip toward irritation and barrier disruption. An over-strong leave-on product can inflame skin and become impossible to use consistently, undermining the very renewal it promised.

The best strength is rarely the biggest. It is the one you can keep.

View the formula

References

Sharad J. Glycolic acid peel therapy: a current review. Clinical, Cosmetic and Investigational Dermatology. 2013;6:281–288. doi:10.2147/CCID.S34029.
Tang SC, Yang JH. Dual effects of alpha-hydroxy acids on the skin. Molecules. 2018;23(4):863. doi:10.3390/molecules23040863.
Kornhauser A, Coelho SG, Hearing VJ. Applications of hydroxy acids: classification, mechanisms, and photoactivity. Clinical, Cosmetic and Investigational Dermatology. 2010;3:135–142. doi:10.2147/CCID.S9042.
Van Scott EJ, Yu RJ. Hyperkeratinization, corneocyte cohesion, and alpha hydroxy acids. Journal of the American Academy of Dermatology. 1984;11(5 Pt 1):867–879. doi:10.1016/S0190-9622(84)80466-1.

Updated May 2026