2% Salicylic Acid Face Wash formula for Acne-Prone Skin?

Table of Contents

Introduction

If you are developing an effective salicylic acid face wash, this free formula gives you everything you need to get started , from the full ingredient list to step-by-step method, pH guidance, and issue-solving tips.

Salicylic acid (SA) is a beta-hydroxy acid (BHA) and one of the most research-supported actives used in acne cleansers. At 2%, it works at the skin’s surface and within pores to help dissolve the plug of oil, dead cells, and debris that causes breakouts.

This formula is designed for DIY formulators and small cosmetic brands who want to create a gel-based, foaming BHA cleanser that is equally functional and gentle enough for daily use.

This post covers the full formulation science behind the product, not just the recipe. By the end, you will understand why each ingredient is chosen, how to safely substitute ingredients, and how to scale your batch with confidence.

Quick Specs

Specification	Detail
Product Type	Foaming gel face wash / cleanser
Best For	Oily, acne-prone, combination skin
Concern Targeted	Acne, clogged pores, excess sebum, blackheads
Finish / Texture	Clear-to-slightly-opaque gel; rich foam lather
Difficulty Level	Intermediate
Batch Size Options	100g (trial) / 500g (small production)
Target pH Range	3.5 – 4.0
Estimated Shelf Life	12 – 18 months (unopened, stored correctly)
Preservative System	Phenoxyethanol & Ethylhexylglycerin (Euxyl PE 9010) @ 1%

Complete Formula Table , 2% Salicylic Acid Cleanser

Batch size: 100g (scale linearly for 500g). All percentages are by weight (w/w).

Phase	INCI / Common Name	%	Function	Notes
A	Water (Aqua)	50.40	Solvent / carrier	Use purified or distilled water only
A	Glycerin	3.00	Humectant, viscosity aid	Helps solubilize salicylic acid slightly
A	Disodium EDTA	0.10	Chelator	Protects preservative efficacy; add to water phase
B	PEG-40 Hydrogenated Castor Oil	2.00	Solubilizer for SA	Critical: dissolves SA in the water phase; prevents turbidity
B	Salicylic Acid	2.00	BHA exfoliant / keratolytic	Must dissolve fully in solubilizer BEFORE adding to water; target pH <4.0
C	Sodium Laureth Sulfate (SLES 70%)	14.00	Primary anionic surfactant	Main foam builder; mild vs SLS; add at cool-down
C	Cocamidopropyl Betaine (CAPB 30%)	8.00	Amphoteric co-surfactant	Boosts foam, reduces irritation, improves feel
C	Lauryl Glucoside	5.00	Non-ionic surfactant	Gentle, skin-compatible; supports sensory profile
C	Cocamide DEA	2.00	Foam stabilizer / thickener	Enhances foam density and viscosity
D	Niacinamide	2.00	Pore-refining, sebum control	Add below 40°C; stable in this pH range
D	Panthenol (D-Panthenol)	0.50	Skin-conditioning, soothing	Helps offset any dryness from SA or surfactants
D	Allantoin	0.20	Soothing, skin-calming	Soluble in water; helps reduce sensitivity
D	Sodium Chloride (NaCl)	1.50	Viscosity modifier	Add incrementally; thickens SLES-based systems
D	Phenoxyethanol & Ethylhexylglycerin (Euxyl PE 9010)	1.00	Preservative	Broad spectrum; stable at low pH; add below 40°C
D	Citric Acid (50% solution)	q.s.	pH adjuster	Adjust to final pH 3.5–4.0; add dropwise, mix well
D	Fragrance / Essential Oil (optional)	0.30	Sensory / masking	Use sparingly; choose pH-stable, non-comedogenic options
	TOTAL	100.00

Phase Overview

Phase A , Water Phase:

The base of the formula. Purified water carries water-soluble ingredients. Glycerin provides initial slip and helps with solubilization. EDTA is added here to deactivate trace metals that might destabilize the preservative.

Phase B , Salicylic Acid Pre-Mix:

This is the most essential phase. Salicylic acid must be dissolved in PEG-40 Hydrogenated Castor Oil (a non-ionic solubilizer) before it is introduced to the water phase. Skipping this step causes cloudiness, crystal formation, or complete instability.

Phase C , Surfactant System:

The cleansing agents are blended and combined into a single surfactant system. Adding them separately and rapidly can cause excessive foaming in the beaker. Gentle stirring is essential here.

Phase D , Cool-Down Actives:

Heat-sensitive ingredients, including niacinamide, panthenol, preservative, and fragrance, are all added at or below 40°C. NaCl is dissolved in a small amount of water first and added here to thicken the system. pH is adjusted last.

Why This Formula Works

The effectiveness of this salicylic acid cleanser comes down to two things: making the BHA bioavailable at the right pH, and building a surfactant system that cleans without stripping.

Salicylic acid is only active meaning it can perform its keratolytic, pore-unclogging function when the formula pH is below 4.0. Above that range, the acid ionizes and loses its ability to penetrate the follicle.

At Formula Chemistry, this formula targets a pH range of 3.5 to 4.0, which keeps SA in its active, undissociated form. The surfactant system is deliberately chosen to be gentler than a standard SLS-only cleanser, using a mixture of SLES, cocamidopropyl betaine, and lauryl glucoside.

This combination delivers rich foam with reduced irritation potential , critical when working with an exfoliating active like SA.

Key ingredient-to-benefit connections:

Salicylic acid @ 2% and pH 3.5–4.0 helps clear pore congestion and may reduce the appearance of blackheads and breakouts.
PEG-40 Hydrogenated Castor Oil solubilizes SA fully, preventing crystallization and guaranteeing even distribution through the formula
SLES + CAPB surfactant blend removes excess oil and surface impurities without disrupting the skin barrier more than necessary
Niacinamide @ 2% may help clearly reduce pore appearance and support oil-control after rinsing.
Allantoin + Panthenol ,soothing and conditioning agents that help offset any potential dryness from the BHA and surfactants
Citric acid pH adjustment , maintains SA in its active state while supporting a mild, skin-compatible environment.

Ingredient Breakdown and Substitutions

Salicylic Acid (BHA)

Formulation role: Oil-soluble keratolytic exfoliant; penetrates pores; antibacterial properties.
Usage range: 0.5–2.0% (2% is the regulatory maximum in many markets for rinse-off OTC products)
Phase & solubility: Slightly soluble in water; requires a solubilizer, do NOT add directly to water
pH compatibility: Active only below pH 4.0; avoid high-pH formulas
Substitution: No direct swap at the same efficacy. Lactic acid (AHA) can provide mild exfoliation at higher pH but will not replicate SA’s oil-solubility or pore-clearing action.

PEG-40 Hydrogenated Castor Oil

Formulation role: Non-ionic solubilizer; essential for dispersing salicylic acid in water-based systems
Usage range: 1–5% depending on active load
Phase: Can be used at room temperature; pre-mix with SA before adding to water
Compatibility: Compatible with anionic and amphoteric surfactants; does not affect foam significantly at these levels.
Substitution: Polysorbate 20 or Caprylyl/Capryl Glucoside at a similar ratio; test for clarity

SLES (Sodium Laureth Sulfate 70%)

Formulation role: Primary anionic surfactant; main foam-builder and cleansing agent
Usage range: 5–15% active surfactant (check active content of your raw material)
Phase: Add in cool-down or at room temperature to avoid excessive foam
Compatibility: Works well with CAPB and non-ionic co-surfactants; avoid mixing with cationic surfactants
Substitution: Sodium Lauroyl Methyl Isethionate (SLMI) for a milder profile; adjust % based on active content

Cocamidopropyl Betaine (CAPB)

Formulation role: Amphoteric co-surfactant; foam booster, irritation reducer, viscosity enhancer
Usage range: 3–10% in combination systems
Phase: Add alongside other surfactants
Compatibility: Broad; compatible with anionics, non-ionics, and most actives
Substitution: Sodium Cocoamphoacetate for a gentler alternative; Disodium Cocoamphodiacetate for a sensitive-skin version

Niacinamide

Formulation role: Skin-conditioning active; may help with visible pore size and sebum balance
Usage range: 2–5% in cleansers (note: rinse-off exposure limits efficacy vs leave-on products)
Phase: Cool-down only , add at or below 40°C to prevent conversion to niacin
Compatibility: Stable at pH 3.5–4.0; sensitive to heat over 50°C; avoid metal contamination
Substitution: Zinc PCA at 0.5–1% for sebum control and mild antimicrobial support

Euxyl PE 9010 (Phenoxyethanol and Ethylhexylglycerin)

Formulation role: Broad-spectrum preservative blend
Usage range: 0.5–1.0%
Phase: Cool-down , add 40 °C below
Compatibility: Effective at pH 3.5–6.0; pairs well with EDTA chelation; do not exceed 1%
Substitution: Optiphen Plus (Phenoxyethanol + Caprylyl Glycol + Sorbic Acid) at the same usage level; also pH-stable

Equipment and Preparation

Tools Required

Digital scale (accurate to 0.01g for small batches)
2–3 glass or stainless steel beakers (100ml–500ml)
Digital thermometer or infrared temperature gun
pH meter (calibrated with buffer solutions) or narrow-range pH strips (3.0–5.0)
Overhead stirrer, hand whisk, or spatula
Dropper or pipette for pH adjustment
Funnel and final container (pump or flip-cap bottle)
Labels for each beaker during the process

Sanitation Steps

Sanitize all equipment with 70% isopropyl alcohol before use.
Work on a clean, dry surface.
Use freshly opened or sealed raw materials.
Wear gloves, salicylic acid can cause mild skin irritation at handling levels.
Use only purified, distilled, or deionized water, never tap water.

Step-by-Step Method

Weigh out Phase A ingredients into your main beaker: distilled water, glycerin, and Disodium EDTA. Stir until the EDTA is fully dissolved. No heat is required, but gentle warming to 30–35°C can help.
In a separate small beaker, combine Phase B: weigh Salicylic Acid and PEG-40 Hydrogenated Castor Oil. Warm gently to 40–45°C and stir until the SA dissolves completely into a clear solution. This may take 3–5 minutes. Do NOT add SA to water before this step.
Add the Phase B pre-mix (SA + solubilizer) into your Phase A water base while stirring gently. The solution should remain clear or turn slightly hazy, this is normal. Stir for 2–3 minutes to fully incorporate.
In a third beaker, combine Phase C surfactants: SLES, CAPB, Lauryl Glucoside, and Cocamide DEA. Stir very gently, avoid whipping air into the mix, as this creates excessive foam and makes weighing and handling difficult.
Add the Phase C surfactant blend slowly into your Phase A+B base. Use a low-speed stir or gentle hand-mixing. The product will begin to build viscosity.
Allow the batch to cool to 40°C or below before proceeding.
Add Phase D ingredients one by one: first dissolve NaCl in a small amount of distilled water (approx 5–10x its weight) before adding to the batch. Stir between each addition. Then add niacinamide, panthenol, allantoin, and preservative (Euxyl PE 9010) in sequence.
Add fragrance or essential oil last if using, and stir gently to incorporate.
Check and adjust pH: Use a calibrated pH meter to test the batch. Target range is 3.5–4.0. Add 50% citric acid solution dropwise to lower the pH if needed. Add a small amount of diluted NaOH (10%) to raise the pH if it overshoots. Stir for 2 minutes after each adjustment and re-check before adding more.
Do a final viscosity check. If too thin, dissolve an additional 0.1–0.2% NaCl in water and incorporate gently. If too thick, add a small amount of distilled water.
Record the final pH and the batch weight. Transfer to your final container and label with date, formula version, and pH.

pH, Stability, and Testing Notes

Target pH and Why It Matters

This formula must be maintained between pH 3.5 and 4.0. Below 3.5, there is a higher risk of skin irritation, especially with daily use. Above 4.0, salicylic acid begins to ionize, losing its effectiveness as a pore-unclogging agent. The preservative system also performs optimally at pH 4.5, so keeping the correct range protects both the active and the product.

How to Measure pH

Always use a calibrated pH meter for accuracy. pH strips are acceptable for initial checks, but may not provide sufficiently precise readings in a surfactant-heavy system. Measure pH directly in the product, surfactant systems do not typically require dilution for pH testing. Calibrate your meter with 4.0 and 7.0 buffer solutions before each session.

Stability Checklist

Day 0: Record baseline, pH, viscosity (pourability), color, clarity, odor
Day 7: Re-test all parameters. Look for cloudiness, separation, or color shift.
Day 14: Freeze-thaw test (freeze for 24h, thaw at room temp), examine for irreversible separation
Day 30: Full re-test. Confirm pH has not drifted more than 0.3 units. Examine for particulates
Elevated temperature test: Place the sample at 40–45°C for 4 weeks to accelerate stability
Accept criteria: No separation, no significant pH drift, no off-odor, clear or consistent appearance.

Preservation and Shelf Life

This formula uses Euxyl PE 9010 (Phenoxyethanol 90% and Ethylhexylglycerin 10%) at 1.0%. This is a well-established, broad-spectrum preservative combination effective against bacteria, yeast, and mold.

It performs reliably in surfactant systems at the target pH range of this formula (3.5–4.0) and is considered relatively low-risk for skin sensitization at this usage level.

The addition of Disodium EDTA at 0.1% acts as a chelator, binding trace metals in the water and formula that would otherwise reduce preservative efficiency. Together, these two components form a strong protection system for an aqueous surfactant product.

The estimated shelf life is 12–18 months for properly preserved batches stored away from direct sunlight and heat. Once opened, recommend use within 6–9 months.

Always advise end users to keep the cap closed and refrain from introducing water into the bottle.

Important: Do not omit the preservative in this formula.

An unpreserved water-based cleanser can become contaminated with bacteria, yeast, or mold within days to weeks particularly in humid bathroom environments. This is a safety risk, not just a stability issue.

Troubleshooting

Problem	Likely Cause	Fix
Formula is too thin / watery	Not enough NaCl or Cocamide DEA	Add NaCl in 0.1–0.2% increments; re-test viscosity after each addition
Formula is too thick / gel-like	Too much NaCl	Dilute with a small amount of water; add in 0.5% increments
Cloudiness / haze in product	Salicylic acid not fully dissolved	Re-dissolve SA in PEG-40 HCO before adding to batch; ensure warm enough
pH too high / SA inactive	Insufficient citric acid	Add 50% citric acid solution dropwise; re-check pH after each addition
Foam is weak or short-lived	Low surfactant level or wrong ratio	Increase CAPB slightly; check SLES concentration (active %); add Cocamide DEA
Skin irritation or tightness	pH too low or SA % too high	Re-check and adjust pH to 3.8–4.0; confirm SA at exactly 2.0%
Preservative failure	pH too high or chelator missing	Ensure pH <4.5 for Euxyl PE 9010; confirm EDTA is present in formula
Color change over time	Niacinamide + heat or metal contamination	Add niacinamide at cool-down only (<40°C); avoid metal utensils
Separation in bottle	Incompatible ingredients or temperature shock	Store away from extreme heat; confirm solubilizer was used for SA

Formula Variations

Variation 1: Sensitive Skin Version

Reduce Salicylic Acid to 1.0% and adjust pH target to 3.8–4.0 (top of the range). Replace Sodium Laureth Sulfate with Sodium Lauroyl Methyl Isethionate (SLMI) at the same active level for a milder lather.

Increase Allantoin to 0.5% and Panthenol to 1.0% to boost the soothing profile. This version is better tolerated by those new to BHA actives or with reactive skin.

Variation 2: High-Cleansing / Oily Skin Version

Increase SLES slightly to 16% and reduce the water % to compensate. Add 0.5% Zinc PCA to the cool-down phase for additional sebum control. Consider adding 0.5% Tea Tree Leaf Oil (solubilized in Phase B) to enhance immunosupport.

This version is designed for significantly oily or congestion-prone skin and should not be used more than once daily.

Variation 3: Hydrating Barrier-Support Version

Add 1.0% Sodium PCA (cool-down) and 0.5% Betaine (water phase) to boost the humectant load. Increase Panthenol to 1.0%. Introduce 0.2% Bisabolol at cool-down for additional calming support.

This version is particularly useful for combination skin types where the T-zone needs BHA action, but the drier zones need extra moisture support during cleansing.

How to Use, Safe Guidance

Recommended frequency: Once or twice daily , morning and/or evening as part of a regular cleansing routine
Patch test: Before first use, apply a small amount to the inner forearm for 24 hours to test for any reaction
Application: Apply a small amount to damp skin, lather gently, and rinse thoroughly with water. Avoid the eye area and mucous membranes.
Sensitivity note: If you are new to salicylic acid cleansers, begin with once-daily use and increase frequency gradually
Precaution: Avoid use on broken, wounded, or severely irritated skin
If irritation, redness, or discomfort occurs, discontinue use immediately and consult a dermatologist if symptoms persist.

Final Summary

This 2% salicylic acid face wash formula provides effective BHA exfoliation at the correct active pH (3.5–4.0) in a gentle, foaming surfactant base.
Key actives: Salicylic acid (2%), niacinamide (2%), allantoin, and panthenol work together to address acne, oiliness, and pore appearance.
The surfactant system (SLES + CAPB + Lauryl Glucoside) supplies a rich lather suitable for oily and combination skin without harsh stripping.
Preserved with Euxyl PE 9010 and chelated with EDTA for a 12–18 month shelf life
Difficulty level: Intermediate salicylic acid solubility calls needing careful pre-dispersion, but the method is clear and repeatable
Suitable for DIY formulators and small brands looking to launch an OTC-style acne cleanser

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2% Salicylic Acid Face Wash Formula for Acne-Prone Skin