Glycolic vs Lactic Acid: Which AHA Is Actually Right for You
Glycolic gets the hype and the higher numbers. But lactic acid does something glycolic can't — and for a lot of skin, that changes the whole calculation.
It is a potent multi-acid peel — 15% glycolic with malic, mandelic and lactic acids, plus fruit enzymes — delivered in a soothing, emollient 'milk' base rather than a bare acid solution. The squalane-and-olive-emollient milk cushions the acids so they exfoliate effectively without the harsh, stripped feel of a clear acid liquid.
A well-built multi-acid exfoliant — a potent 15% glycolic acid with three more AHAs and fruit enzymes, cushioned in a soothing 'milk' base, fragrance-free. It smooths texture and brightens effectively, and the milk format genuinely softens the experience. At standout value; still a real, potent peel that sensitive skin should approach with care.
Note: This peel is a recent Prequel product and our assessment combines ingredient analysis with a growing body of real-world feedback. This review will be refreshed as the product's track record lengthens.
The case for it
Same rule for everyone. “Good choice” is the verdict on 9,564 of 45,024 concern verdicts across the catalog; rule R5 decided 9,072 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
The case for it
Same rule for everyone. “Good choice” is the verdict on 9,564 of 45,024 concern verdicts across the catalog; rule R5 decided 9,072 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
The case for it
Cautions: a photosensitising active — use sun protection.
What would change this: Guideline or regulatory standing for the active on this concern would move this from a promising bet to a recommendation.
Same rule for everyone. “Promising” is the verdict on 7,858 of 45,024 concern verdicts across the catalog; rule R9p decided 7,858 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
The case for it
Same rule for everyone. “Not for this” is the verdict on 488 of 45,024 concern verdicts across the catalog; rule R10 decided 488 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
The case for it
Cautions: fungal-acne triggers.
What would change this: Guideline or regulatory standing for the active on this concern would move this from a promising bet to a recommendation.
Same rule for everyone. “Promising” is the verdict on 7,858 of 45,024 concern verdicts across the catalog; rule R9p decided 7,858 of them. Unchanged since September 5, 2026, engine 5.1.1.
Brand or formulator? Disclose a concentration or correct a fact →
The studies behind the evidence row
Where our review and the verdict differ. The review below was written on the formulation and the published trials; the verdicts above apply the stricter standing test in our methodology — an active earns a recommendation only with guideline or regulatory standing for the concern. Where the two disagree, the verdict is DermApproved’s position.
A verdict is DermApproved’s assessment of how well a product’s ingredients fit a concern — never a claim about what the product treats. Evidence dots and collected reviews sit beside it and are never blended in. Rules 0.5.1 · evidence table ev-2026.09-r228 · how we decide
The Prequel Multi-Acid Milk Peel has a soft, reassuring name. 'Milk' suggests something gentle, mild, soothing — the opposite of the word 'peel,' which suggests something intensive. So the first job of an honest review is to explain exactly what the 'milk' in this product is, because misreading it leads to one of two mistakes: either underestimating a genuinely potent product, or being put off a genuinely comfortable one.
Here is the truth of it. The 'milk' refers entirely to texture and vehicle — not to strength. Most acid peels and exfoliating solutions are bare, watery, clear liquids: the acids dissolved in not much else. They are effective, but they can feel harsh, and they can leave skin tight and stripped. Prequel's approach is to take a potent multi-acid blend and formulate it into a milky, lightly emollient base — squalane, olive-derived emollients, glycerin — that cushions the acids as they work. The result genuinely feels softer on the skin: a mild tingle rather than a sharp sting, no stripped after-feel. That is real, and it is the product's nicest quality. But here is the crucial qualifier: the milk does not weaken the acids. Look at the formula — 15% glycolic acid, the lead, a genuinely potent exfoliating strength, plus malic, mandelic and lactic acids, plus lipase and protease enzymes. This is a real, multi-mechanism, effective peel. The milk makes it comfortable; it does not make it gentle in the sense of weak. Read 'milk' as 'cushioned,' not as 'mild,' and you will treat the product correctly.
The multi-acid-and-enzyme construction is genuinely smart, and worth understanding. Rather than relying on one acid at a very high concentration, the peel spreads the exfoliating work across several. Glycolic acid, the small and penetrating one, does the main job of dissolving dull surface cells. Lactic acid, gentler and a humectant itself, broadens the effect while softening intensity. Mandelic acid, the largest-moleculed and slowest, adds a gentler layer. Malic acid rounds out the AHAs. And then lipase and protease — enzymes — add a non-acid exfoliating mechanism, breaking down surface debris and dead-cell proteins. Several gentler routes, working together, can resurface thoroughly while feeling more comfortable than a single harsh acid. It is a thoughtful, dermatologically minded design, fitting for a brand founded by one.
Used as directed, it delivers. Skin looks smoother and more radiant within a week or two, and over four to eight weeks the look of texture, pores and uneven tone genuinely improves. The milky liquid spreads easily, absorbs without residue, and the cushioned feel makes it a pleasant step in an evening routine rather than a chore to brace for. There is no perfume to contend with, either, which suits a product applied to freshly exfoliating skin.
It helps to be honest about who should hold back, because the milk texture can lull people into treating this casually. Genuinely sensitive, reactive or rosacea-prone skin may find even a cushioned 15% glycolic blend more than it wants, and a gentler single-acid product is the wiser starting point there. Skin already running a retinoid needs to alternate nights rather than stack, and anyone unwilling to commit to daily sunscreen should not be using AHAs at all. For normal, combination and oily skin prepared to introduce it slowly and protect the results, though, this is a peel that rewards patience with steadily smoother, brighter, more even-looking skin.
There is a sensible rhythm to working it into a routine, and it rewards a little discipline. Two nights a week is the right starting cadence, applied to dry skin after cleansing and followed with a hydrating serum and moisturizer; frequency can climb gradually as skin proves it can cope. Acid nights and retinoid nights stay separate, alternated rather than stacked. And because every alpha hydroxy acid leaves skin more vulnerable to UV, daily broad-spectrum sunscreen is not optional but the other half of the treatment. Used with that small amount of structure, the peel does steady, genuine work without ever tipping skin into the raw, over-exfoliated state that gives acids a bad name.
Its limits are the ones any potent acid product carries, plus the milk-related misconception already addressed. Fifteen percent glycolic acid is potent, full stop — so this needs gradual introduction. Begin two nights a week, start with shorter contact if your skin is acid-sensitive, and build up; do not go nightly out of the gate. Genuinely sensitive or rosacea-prone skin should be cautious or choose a gentler single-acid product. It cannot be layered with a retinoid or other exfoliants in the same routine. And, universally for acids, daily sunscreen is non-negotiable, since AHAs increase sun sensitivity. The emollient milk base also means it is not fungal-acne safe.
Value, finally, is exceptional, and characteristically Prequel. Twenty-three dollars for a generous 226 mL bottle of a well-formulated, dermatologist-developed multi-acid peel is remarkable — used two or three nights a week as it should be, that bottle lasts months, and the per-use cost is close to nothing. To sum up: this is a genuinely good, intelligently constructed multi-acid exfoliant, and the milk format is a real, welcome innovation in comfort. Buy it understanding that 'milk' means cushioned, not weak — introduce it like the potent peel it is, wear your sunscreen — and it is one of the best-value resurfacing treatments you can put in a routine.
The hero actives that drive this product's performance.
| Ingredient | Function | Evidence |
|---|---|---|
| Glycolic Acid (15%) (15%) | The lead acid at a stated 15% — glycolic is the smallest, most penetrating AHA, doing the primary work of dissolving dull, built-up surface cells to smooth texture and brighten tone. It is a genuine, potent exfoliating strength, here cushioned in a soothing milk base. | Established mechanism for Rough Texture · established mechanism |
| Lactic Acid | A gentler, larger-moleculed AHA that also acts as a humectant — it broadens the surface exfoliation while softening the overall intensity, part of why this peel exfoliates without feeling harsh. | Established mechanism for Rough Texture · established mechanism |
| Mandelic Acid | The largest-moleculed AHA in the blend, the gentlest and slowest-penetrating — with malic acid, it rounds out a multi-acid mix that exfoliates from several angles at once rather than relying on glycolic alone. | Limited for Blackheads |
| Fruit Enzyme Complex (Lipase, Protease) | Lipase and protease enzymes that break down surface debris and dead-cell proteins — a gentle, non-acid route to exfoliation that works alongside the acids, adding a second mechanism to the 'multi' in Multi-Acid. | Not yet assessed |
| Squalane | A lightweight, skin-identical emollient — with olive-derived emollients and glycerin it creates the soothing, milky, cushioned base that buffers the acids, so the peel smooths the skin without the tight, stripped feel of a bare acid solution. | Not yet assessed |
Ingredient standings describe the active at treatment-level doses and vehicles; this product's own condition grades weigh its actual formula.
Water (Aqua), Glycolic Acid, Sodium Hydroxide, Glycerin, Propanediol, Ethylhexyl Olivate, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, C13-14 Isoalkane, C11-12 Isoalkane, Phytic Acid, Malic Acid, Mandelic Acid, Lactic Acid, Lipase, Protease, Squalane, Polyglyceryl-10 Stearate, C15-23 Alkane, Hydroxyacetophenone, Phenoxyethanol, Tricaprylin, Glyceryl Oleate, Ethylhexyl Polyhydroxystearate, Tetradecane, C13-14 Alkane, Decyl Glucoside, Maltodextrin, Xanthan Gum, Lecithin, Sclerotium Gum, Polyglyceryl-4 Oleate, Carrageenan, Silica
treatment
PM
Use in the evening on clean skin. Start two nights a week, applying an even layer, and build up as tolerated. Begin with shorter contact if your skin is acid-sensitive. Do not layer it with a retinoid or other exfoliants in the same routine, and apply sunscreen every morning.
Skin often looks smoother and more radiant within the first week or two. Improvement in the look of texture, pores and uneven tone builds over 4-8 weeks of consistent use.
This is a well-constructed multi-acid exfoliant combining acids and enzymes. Glycolic acid, the lead at a stated 15%, is the most-studied AHA, with robust evidence for stratum corneum exfoliation and improvement of texture, tone and the appearance of hyperpigmentation; 15% is a potent, effective concentration. Lactic acid is a gentler AHA with humectant properties; mandelic acid, with a larger molecular size, penetrates more slowly and is the gentlest of the group; malic acid contributes additional alpha-hydroxy activity. Phytic acid adds a mild exfoliating and antioxidant role. Lipase and protease are enzymes that catalyze the breakdown of lipids and proteins respectively, providing a non-acid exfoliating mechanism with promising, if less extensive, evidence.
The distinctive formulation feature is the emollient 'milk' vehicle — squalane, olive-derived emollients and glycerin. Buffering acids within an emollient base is a recognized way to improve tolerability: it does not reduce the acids' concentration, but it cushions application and limits the stripped after-feel, which can improve adherence and comfort without compromising efficacy.
The key caveats are standard for potent AHA products. Glycolic acid at 15% carries genuine irritation potential, warranting gradual introduction and caution for sensitive or compromised skin. AHAs increase photosensitivity, making daily sunscreen essential, and exfoliating acids should not be layered with retinoids or other exfoliants in the same routine. The realistic, evidence-aligned outcome is gradual, genuine improvement in skin texture, radiance and tone with consistent, appropriately spaced use.
Dermatology supports alpha-hydroxy acid exfoliation for texture, tone and dullness, and glycolic acid at concentrations around 10-15% is regarded as effective for at-home use. A multi-acid blend at modest individual strengths, combined with enzymes, aligns with the well-regarded principle of spreading exfoliation across gentler mechanisms rather than relying on a single high-concentration acid. Clinicians would clarify, as this review does, that an emollient 'milk' base improves comfort and tolerability but does not lower the acids' strength — a 15% glycolic formula remains a potent exfoliant requiring respect. Standard clinical guidance matches best use: introduce gradually, start with low frequency and shorter contact, do not combine with retinoids or other acids in the same routine, and apply daily broad-spectrum sunscreen, since AHAs increase photosensitivity. Sensitive or rosacea-prone skin is generally steered toward gentler options such as PHA exfoliants. Dermatologists would view this as a sound, well-designed multi-acid exfoliant for non-sensitive skin, with the consistent reminder that over-exfoliation damages the barrier and that less-frequent, well-tolerated use outperforms aggressive use.
Work this into the evening, after cleansing, on dry skin. Begin with two nights a week, spreading an even layer over the face and steering clear of the eye area; if your skin is acid-sensitive, keep the first applications to shorter contact times. Build frequency gradually as your skin tolerates it, and follow with a hydrating serum and moisturizer. Keep it off the same night as a retinoid or other exfoliating acids — alternate them instead. A broad-spectrum sunscreen every morning is essential, since AHAs increase sun sensitivity.
At around $23 for a generous 226 mL bottle, the Multi-Acid Milk Peel is outstanding value. Used two to three nights a week as recommended, the large bottle lasts roughly three to five months, making the per-use cost very low for a well-formulated, dermatologist-developed multi-acid exfoliant. The acids themselves — glycolic, lactic, mandelic, malic — are well-understood, inexpensive ingredients, but the formulation work here is real: the multi-acid-and-enzyme blend and the cushioning milk base are a thoughtful construction, not a bare acid solution. Compared with multi-acid exfoliants and peels from mid-range and prestige brands, which often run $30 to $60 for far smaller volumes, Prequel's pricing is exceptional, consistent with its accessible-derm-skincare positioning. For an effective at-home resurfacing treatment, the value is among the best in the category.
Normal, combination or oily skin wanting an effective at-home multi-acid exfoliant to smooth texture, brighten dullness and refine the look of pores will get on well with this, especially anyone who appreciates a peel that feels cushioned rather than harsh. For regular, ongoing use, it is excellent value.
Genuinely sensitive or rosacea-prone skin should be cautious with a 15% glycolic formula and may prefer a gentler single PHA exfoliant. Anyone already using a retinoid should plan to alternate rather than layer, and those needing a fungal-acne-safe product should look elsewhere.
A soft, milky liquid — lightly emollient rather than a bare watery acid solution. It spreads smoothly, absorbs without residue, and feels cushioned on the skin.
Unscented in practice, with a barely-there neutral note.
Generous 226 mL bottle in Prequel's clean design. The large format suits regular use; a pump or controlled opening helps dose the milky liquid.
First use feels surprisingly gentle for a 15% glycolic peel — the milky, emollient texture cushions the application, with at most a mild tingle rather than a sharp sting. Skin feels smoother within days. Some mild dryness in the first week or two is normal as skin adjusts; introduce it gradually.
About 3-5 months using it two to three nights a week
All Year
Prequel, founded by dermatologist Dr. Samantha Ellis, designed the Multi-Acid Milk Peel to make a genuinely potent acid peel more comfortable to use. The 'milk' is the point: a multi-acid-and-enzyme blend formulated into an emollient, cushioned vehicle, in a generous, affordably priced bottle.
Prequel is a skincare brand founded in 2022 by Dr. Samantha Ellis, a board-certified dermatologist, positioned as accessible, science-based dermatologist-developed skincare. As a recent brand its long-term track record is still limited, but its formulations are genuinely derm-developed.
A 'milk' peel is a gentle, low-strength peel.
The 'milk' refers to the soothing, emollient texture, not to a weak formula. This peel contains 15% glycolic acid plus three more AHAs and enzymes — a genuinely potent exfoliating blend. The milk base buffers and cushions the experience; it does not water down the acids. Treat it as a real peel.
Combining several acids makes a peel harsher than a single-acid one.
Not necessarily. Using glycolic, malic, mandelic and lactic acids together — at modest individual strengths and in a buffered, emollient base — can exfoliate thoroughly while feeling more comfortable than one acid at a very high concentration. The multi-acid-plus-enzyme approach spreads the work across several gentler mechanisms.
It is a multi-acid exfoliating treatment — 15% glycolic acid with malic, mandelic and lactic acids, plus lipase and protease enzymes — delivered in a soothing, emollient 'milk' base. It smooths texture, brightens tone and refines the look of pores, with the milk base buffering the potent acids.
The 'milk' refers to the cushioned, emollient texture, not to a low strength. The formula contains a genuinely potent 15% glycolic acid plus three more AHAs and enzymes. The milk base makes the experience more comfortable — less of the harsh, stripped feel — but it is still a real, effective peel that needs gradual introduction.
Start two nights a week and build up as your skin tolerates it. Despite the soothing texture, the 15% glycolic acid is potent, so introducing it gradually avoids irritation. Always follow with moisturizer, apply sunscreen daily, and do not use it on the same night as a retinoid or other exfoliants.
It is gentler in feel than a bare acid solution, but the 15% glycolic acid means it is still a potent exfoliant. Genuinely sensitive or rosacea-prone skin should be cautious — patch test, start with short contact and low frequency, or choose a gentler single PHA exfoliant instead.
Yes — at around $23 for a generous 226 mL bottle, it is excellent value. Used two to three nights a week, the large bottle lasts several months, making the per-use cost very low for a well-formulated, dermatologist-developed multi-acid peel.
Recurring themes our editors read across retailer reviews of this product — summaries in our words, not quotations, and not a substitute for your own patch test.
Visibly smooths texture and boosts radiance with regular use
Milk base makes a potent acid blend feel comfortable, not harsh
Multi-acid and enzyme blend exfoliates from several angles
Generous bottle at an excellent price
15% glycolic acid is still potent — too much for sensitive skin
Needs gradual introduction and careful frequency
Cannot be layered with a retinoid in the same routine
Not fungal-acne safe, owing to the emollient base