A CPSR for shampoo is legally mandatory before the product goes on sale anywhere in the EU, exactly like every other cosmetic. What makes haircare interesting is that the rules cut both ways: the rinse-off retention factor gives you real formulation freedom on systemic safety, while the eye area, the scalp and the sheer volume consumers use pull in the other direction.
Understanding which way each factor pushes is the difference between a smooth assessment and a formula that comes back needing changes. This guide covers what a safety assessor looks at in a shampoo or conditioner, which tests you actually need, where haircare formulas typically fail, and what to have ready before you commission the report.
Key takeaways
- Shampoos and conditioners are cosmetics under Regulation (EC) No 1223/2009 — a CPSR is mandatory, with no exemption for small batches.
- The rinse-off retention factor of about 0.01 substantially reduces systemic exposure compared with leave-on products.
- But the standard daily amount is high — 10.46 g for shampoo — and eye contact is a foreseeable use, so ocular tolerance matters.
- Water-based haircare almost always needs preservative efficacy testing (ISO 11930) and microbiological limits (ISO 17516).
- Leave-in conditioners are not rinse-off — the retention factor changes to 1 and the assessment is materially stricter.
- Common problem areas: preservative levels, fragrance allergens, colorant selection, MIT/MCI sensitisers and pH.
- Anti-dandruff and anti-hair-loss claims risk pushing the product into medicinal or biocidal territory.
Why haircare is assessed differently
The single most important number in a shampoo assessment is the retention factor. For rinse-off products, the SCCS Notes of Guidance apply a factor of approximately 0.01 — reflecting that only around 1% of what you apply remains on the skin after rinsing.
That two-order-of-magnitude reduction flows straight into the systemic exposure calculation, which is why an ingredient that fails at 0.5% in a body lotion can pass comfortably at the same level in a shampoo. Our guide to how the margin of safety is calculated walks through the arithmetic.
But the offsetting factors are real:
| Factor | Effect on the assessment |
|---|---|
| Retention factor ~0.01 | Strongly favourable — systemic exposure drops ~100× |
| Daily amount 10.46 g (shampoo), 14 g (conditioner) | Unfavourable — much higher than a face cream at 1.54 g |
| Foreseeable eye contact | Unfavourable — ocular tolerance data expected |
| Scalp application | Unfavourable — higher follicle density and vascularity |
| Warm, wet use environment | Unfavourable — enhanced penetration; contamination risk in use |
| Frequent, lifelong use | Unfavourable — chronic exposure, sensitisation risk |
| High water content | Unfavourable — microbiological risk requires preservation |
The leave-in trap: leave-in conditioners, hair oils, heat protectants and styling creams are not rinse-off products. The retention factor becomes 1, systemic exposure rises roughly a hundredfold, and a formula that was comfortably safe as a rinse-out conditioner can fail as a leave-in. If you are extending a rinse-off range into leave-in formats, the safety assessment does not carry over — tell your assessor the real use pattern.
What your assessor examines
Surfactants and eye irritation
Anionic surfactants — sodium lauryl sulfate, sodium laureth sulfate, and their derivatives — are the workhorses of cleansing and the main driver of ocular irritation potential. Because getting shampoo in the eyes is entirely foreseeable, an assessor will want to see that the surfactant system has been evaluated for eye irritation.
In vitro methods (HET-CAM, BCOP, EpiOcular or equivalent) are the standard route, and are essential if you intend to make a “no tears” or “gentle on eyes” claim. Note that surfactant combinations behave non-linearly — amphoterics such as cocamidopropyl betaine are usually added to reduce irritation, but at high proportions of the total surfactant load they can increase it. Test the actual finished formula, not the individual raw materials.
Preservation
Shampoo is typically 70–90% water, used in a warm humid environment, with wet hands repeatedly entering the pack. It is a demanding preservation challenge and one of the most common reasons a haircare assessment stalls.
You will need preservative efficacy testing to ISO 11930 on the finished formula in its final packaging, plus microbiological limits to ISO 17516. Our guide to which cosmetic tests you actually need covers the full set.
Watch the Annex V limits, particularly:
- Methylisothiazolinone (MIT) — permitted in rinse-off only, at 0.0015%. It is prohibited in leave-on products entirely.
- Methylchloroisothiazolinone/Methylisothiazolinone (MCI/MIT) — rinse-off only, 0.0015% of the 3:1 mixture, and it cannot be combined with MIT alone in the same product.
- Phenoxyethanol — 1.0%.
- Sodium benzoate / potassium sorbate — pH-dependent efficacy; they need a formula below roughly pH 5.5 to work, which conflicts with the pH many haircare formulas target.
The isothiazolinones are potent contact sensitisers and a major cause of allergic contact dermatitis in Europe. They remain legal in rinse-off at the Annex V levels, but many brands have moved away from them for sensitive-scalp positioning. If you use them, get the level exactly right — an over-dose is both a compliance breach and a real consumer safety issue.
Fragrance allergens
Haircare is heavily fragranced, and the expanded allergen declaration list under Regulation (EU) 2023/1545 hits it hard. Where the previous regime required 26 fragrance allergens to be declared above the threshold, the amended Annex III expands this to more than 80.
The declaration thresholds are unchanged in principle — 0.001% for leave-on and 0.01% for rinse-off — so shampoos benefit from the tenfold higher threshold. Even so, a typical fragranced shampoo will now declare considerably more allergens than before. Request a full allergen breakdown from your fragrance house at your actual dosage, not a generic certificate. Our guide to the new fragrance allergen labelling requirements covers the timeline and what to do about existing artwork.
pH and physicochemical properties
Hair and scalp tolerate a fairly wide pH range, but assessors will look at whether your pH is appropriate for the format. Shampoos typically sit around pH 4.5–6.0, conditioners lower at around 3.5–4.5 to help close the cuticle. A markedly alkaline formula needs justification, and a strongly acidic one may raise irritation questions.
pH, viscosity, density and appearance normally come from a certificate of analysis on the finished product and feed directly into the CPSR Part A dataset.
Colorants
Only colorants listed in Annex IV may be used, and several carry a rinse-off-only restriction — which is convenient for shampoo but not for a leave-in extension of the same range. Check each colorant’s Annex IV conditions against the actual product type rather than the range as a whole.
Stability, packaging and PAO
Accelerated stability and packaging compatibility testing establishes shelf life and the period after opening, and for haircare it also catches practical failures: phase separation in conditioners, viscosity drift in surfactant systems over temperature cycling, fragrance discolouration, and interaction between cationic conditioning agents and the pack.
Since most shampoos have a shelf life above 30 months, you will normally use the PAO symbol rather than a date of minimum durability. Twelve months is typical for haircare. Our accelerated stability and compatibility test covers both shelf life and pack compatibility.
Test in the pack you will actually ship. A conditioner that is stable in a glass laboratory jar can behave differently in an HDPE bottle with a flip-top cap, and cationic ingredients are notorious for interacting with packaging. Late pack changes are a common reason stability work has to be repeated.
Claims: where haircare gets dangerous
More than most categories, haircare marketing edges toward claims that change the product’s legal classification.
| Claim | Risk |
|---|---|
| “Reduces hair loss” / “stops hair fall” | Medicinal by presentation — treating a physiological condition |
| “Stimulates hair growth” | Medicinal by function |
| “Treats dandruff” (vs “helps reduce visible flakes”) | Medicinal — seborrhoeic dermatitis is a condition |
| “Kills bacteria on the scalp” | Potentially biocidal — outside cosmetic scope |
| “Anti-lice” / “eliminates head lice” | Biocidal or medical device, not cosmetic |
| “Repairs damaged hair” | Acceptable if framed as appearance/condition and substantiated |
| “Strengthens” / “reduces breakage” | Acceptable with instrumental substantiation |
Anti-dandruff formulas are the most common borderline case. Zinc pyrithione — long the standard anti-dandruff active — is now prohibited in cosmetic products in the EU following its CMR classification, which forced a category-wide reformulation onto piroctone olamine, climbazole, salicylic acid and selenium disulfide. Each has its own Annex III conditions and its own claim limits. Our guide to classifying borderline products covers where the lines fall, and permitted cosmetic claims covers substantiation.
What to have ready
To commission a CPSR for a shampoo or conditioner, assemble:
- Exact quantitative formula — percentages, not ranges, with the full composition of every compound raw material.
- Raw material documentation — specifications, safety data sheets, CoAs, allergen and impurity data, and confirmation of Annex compliance.
- Fragrance allergen declaration at your actual dosage, covering the expanded list.
- Manufacturing method and a GMP statement (ISO 22716).
- Finished product CoA — pH, viscosity, density, appearance, odour.
- Stability and packaging compatibility report.
- Preservative efficacy test (ISO 11930) and microbiological limits (ISO 17516).
- Ocular tolerance data, particularly for any eye-related claim.
- Packaging specification — material, closure, applicator.
- Draft artwork with the INCI list, warnings and claims.
- Intended use stated precisely — rinse-off or leave-in, adult or child, frequency.
Our full checklist of documents needed to order a CPSR covers each item and why the assessor needs it.
Bringing it all together
Haircare is one of the more forgiving categories on systemic safety and one of the less forgiving on everything else. The rinse-off retention factor gives you room to work with actives and preservatives that a leave-on product could not carry, but the eye contact, the scalp, the water content and the frequency of use mean the ocular, microbiological and sensitisation sides of the file need to be solid.
Get three things right and the assessment is straightforward: a preservation system that passes ISO 11930 in the real pack, a surfactant blend with in vitro ocular data behind it, and claims that stay on the cosmetic side of the line. Get the use pattern wrong — assessing a leave-in as a rinse-off — and you will be doing it twice.
Lexora prepares safety assessments for haircare across rinse-off and leave-in formats, and can arrange the testing alongside them. The Water-Based Cosmetic Safety Package bundles the CPSR with the microbiological, challenge and stability testing that water-based haircare needs, or start with a standalone CPSR.
Frequently asked questions
Does shampoo really need a CPSR?
Yes. Shampoo is a cosmetic product under Regulation (EC) No 1223/2009, and Article 10 requires a safety assessment before it is placed on the market. There is no exemption for small producers, handmade products or low-volume batches. The CPSR must be signed by a qualified safety assessor and held in the Product Information File.
Is a conditioner assessed the same way as a shampoo?
A rinse-out conditioner is assessed on the same rinse-off basis, though with a slightly higher standard daily application amount. A leave-in conditioner is entirely different: the retention factor changes from about 0.01 to 1, so systemic exposure rises roughly a hundredfold and the assessment is considerably stricter. Always tell your assessor which it is.
Do I need eye irritation testing for a shampoo?
Eye contact is a reasonably foreseeable use, so an assessor will expect the surfactant system to have been evaluated for ocular irritation potential — normally through in vitro methods such as HET-CAM, BCOP or EpiOcular. It becomes essential if you want to make any “gentle on eyes”, “no tears” or children’s product claim.
Can I still use MIT or MCI/MIT in shampoo?
Yes, within Annex V limits — both are permitted in rinse-off products only, at 0.0015%, and MCI/MIT as the 3:1 mixture cannot be combined with MIT alone in the same product. They are prohibited in leave-on products. They are also significant contact sensitisers, so many brands have moved away from them for sensitive-scalp ranges.
Can I say my shampoo is anti-dandruff?
Carefully. Framing it as cosmetic — helping reduce visible flakes and relieving the appearance of a flaky scalp — is generally acceptable with substantiation. Claiming to treat dandruff as a medical condition risks medicinal classification. Note also that zinc pyrithione, the traditional anti-dandruff active, is now prohibited in EU cosmetics, so check your active against the current Annexes.
What PAO should I put on a shampoo?
Twelve months is typical for haircare, but the figure must be justified by your stability and preservative efficacy data rather than chosen by convention. If the total shelf life is 30 months or less you use a date of minimum durability instead of a PAO. Your stability report should support whichever you declare.
How does the expanded fragrance allergen list affect haircare?
Regulation (EU) 2023/1545 expands the individually declarable fragrance allergens from 26 to more than 80. Rinse-off products benefit from the higher 0.01% declaration threshold compared with 0.001% for leave-on, but most fragranced shampoos will still declare more allergens than before. Ask your fragrance supplier for a breakdown at your actual dosage — see our guide to the new allergen labelling rules.
