BUTTER-C
Signature ingredients
Iron oxide tinted sunscreen OEM/ODM manufacturing
Iron Oxide Tinted Sunscreen · OEM/ODM
Iron oxides are red, yellow and black pigment powders, listed on the label by their color index numbers CI 77491, CI 77492 and CI 77499 — the "palette" of foundations and tinted sunscreens. Blending these three colors with pigmentary titanium dioxide in different ratios gives many shades, enough to cover the range of skin types (Lyons et al., 2021). One point needs to be clear from the start: iron oxides are not UV filters. They are colorants under ASEAN Annex IV and are not on the Annex VII list of UV filters; SPF and UVA come from the filters — on this page Butter-C proposes zinc oxide and/or titanium dioxide. The reasons to add iron oxides are a cream that matches skin tone, less white cast from mineral filters, and a body of data drawing attention: visible light can cause hyperpigmentation in people with darker skin, broad-spectrum sunscreens do not protect adequately against this range, and to block it the product layer has to be visible on the skin (Lyons, 2021). In a study in 12 volunteers, the tinted products protected better against visible light plus UVA1 than the untinted ones (Ezekwe et al., 2024) — a result of the whole formulas, a small sample, limited evidence. That is why a visible light statement is made only after testing the finished product itself. This page differs from the general sunscreen page and from the zinc oxide and titanium dioxide pages because the main task is color: each shade is a separate formula, every lot is color-matched, SPF is measured for each shade, and the pigments are checked for metal impurities. Butter-C offers turnkey OEM/ODM manufacturing, from formula development and coordination of sun protection testing to labeled finished goods and the notification dossier.
Formula base
Mineral filters carry the SPF, iron oxides carry the color
A tinted sunscreen is two systems layered together: the filter system determines SPF and UVA; the pigment system determines shade, coverage and white cast. Butter-C checks the current Annex VII (version 2025-2, 12 December 2025) and Annex IV as reported in our iron oxide article when building the formula.
Iron Oxides (CI 77491, 77492, 77499)
Red: Fe2O3, CAS 1309-37-1; yellow: hydrated iron(III) oxide, CAS 51274-00-1; black: Fe3O4, CAS 1317-61-9. According to our iron oxide article, ASEAN Annex IV Part 1 (version 2026-1, 22 June 2026) places all three in column 1 — colorants allowed in all cosmetic products — with the conditions column left blank; there is no entry in Annex II, III, VI or VII. The raw material comes as dry powder, surface-treated powder or ready-made dispersion; the surface coating agent must also appear in the ingredient list.
Filter: zinc oxide
Annex VII Ref A29 (zinc oxide) and Ref A29a ("Zinc Oxide (nano)"): maximum 25%; footnote (2): when both forms are used, the sum may not exceed 25%. Both entries state "Not to be used in applications that may lead to exposure of the end-user's lungs by inhalation". Zinc oxide dissolves in dilute acid, so no acids are combined in the same formula — details on the zinc oxide sunscreen page.
Filter: titanium dioxide
Annex VII Ref 27 (titanium dioxide) and Ref 27a ("Titanium dioxide (nano)"): maximum 25%; footnote (4): when both forms are used, the sum may not exceed 25%. Ref 27 refers powders containing 1% or more of particles with an aerodynamic diameter ≤ 10 µm to Annex III Ref 338; the sentence "Not to be used in applications that may lead to exposure of the end-user's lungs by inhalation" appears in Ref 27a and in Annex III Ref 338 point c. Footnote (3): for titanium dioxide used as a colorant, see Annex IV, CI 77891.
Titanium dioxide as both filter and pigment
Skin shades are built from iron oxides together with pigmentary titanium dioxide (Lyons, 2021). Annex VII does not say how to count a substance that plays both roles; Butter-C provisionally counts all titanium dioxide in the formula toward the 25% limit of Ref 27/27a. This is Butter-C's cautious reading, not wording from the regulation — how it is listed and calculated must be confirmed by regulatory affairs for each dossier.
Oil base, emulsifier, dispersion
Esters such as C12-15 Alkyl Benzoate and Caprylic/Capric Triglyceride wet the powders; a water-in-oil emulsion with Polyglyceryl-2 Dipolyhydroxystearate and an electrolyte in the water phase. Pigments are milled in oil or bought as ready-made dispersions, and fineness is checked before they go into the base so the cream does not streak (manufacturing practice).
Key technical points
Four issues specific to a tinted sunscreen
The four items below are settled on the sample before it goes for SPF testing — changing the pigment source, color ratio, filter powder source or oil ratio after testing can change the result.
Iron oxides do not replace filters
Iron oxides are not in Annex VII; a tinted cream still needs a filter system sufficient for the target value. Color and filters also interact: in an early experiment using transmission spectra and tests in guinea pigs, a white paste with 20% zinc oxide protected poorly against visible light even when applied thickly, while adding pigments such as iron oxide lowered transmission more than the product of the individual components (Kaye et al., 1991). Any color change made after SPF testing therefore means testing again.
Visible light: how far the data go
Ezekwe (2024) irradiated the backs of 12 volunteers with visible light plus UVA1 (370–700 nm) and followed them for 14 days: the product with 11% titanium dioxide, 1% iron oxides and antioxidants gave the highest and most consistent protection; the product with 12% zinc oxide, organic filters and 4% iron oxides showed some efficacy — the authors say further studies are needed to see whether iron oxide content correlates with protection. Ruvolo (2026; 12 people with darker skin; all three authors work for a cosmetics company) found that not every mineral formula with iron oxides significantly reduced redness and pigmentation compared with a zinc-oxide-only formula. The conclusion for formulation: the overall formula matters, not just the iron oxide percentage.
Each shade is a separate formula
Each shade is a different combination of iron oxides and pigmentary titanium dioxide (Lyons, 2021), so absorption spectrum, viscosity and skin feel also differ. Butter-C color-matches every lot against the approved reference sample with a colorimeter and under standard lighting; SPF and UVA are measured for each shade, or by a shade-grouping approach accepted by the testing laboratory and regulatory affairs.
Metal impurities in pigments
The ASEAN guideline notes that heavy metals may be found in pigments. Wang et al. (2022) measured 10 inorganic pigments: colored pigments contained 7.6–21.2 µg/g nickel, more than white pigments; nickel dissolved into artificial sweat from three pigments, including hydrated iron oxide. Each iron oxide lot needs a certificate of analysis (COA) for arsenic, lead and mercury, plus nickel when the client positions the product for sensitive skin; the finished product meets the heavy metal limits of Appendix 06-MP and the ASEAN guideline.
Nanoparticles and inhalation
According to Lyons (2021), nano zinc oxide and titanium dioxide do not block visible light — that part relies on the pigments. If nano filters are used, the material must meet all criteria of Ref A29a or Ref 27a. Annex IV sets no particle size condition for the three iron oxide CI numbers, and no specific data were found on nano iron oxides applied to human skin (our iron oxide article): a nano grade needs its own particle size dossier and safety assessment. This product is not made as a spray or powder.
Three formulation directions
Three formats of iron oxide tinted sunscreen
Tinted mineral zinc oxide cream
Zinc oxide as the main filter, possibly with titanium dioxide; iron oxides match the skin tone and hide the white cast on darker skin. For people who want to avoid organic filters. The water phase must not drift into the acid range; "broad spectrum" is labeled only once UVA has been measured on the finished product.
Tinted titanium dioxide cream
Close to product D in the Ezekwe (2024) study — 11% titanium dioxide, 1% iron oxides and antioxidants, which gave the highest and most consistent protection of the four products tested. That result belongs to that whole formula and does not transfer to another formula. Titanium dioxide is strongest in UVB, so the UVA side needs zinc oxide or confirmation by testing; a coated grade is chosen to reduce photocatalysis (see the titanium dioxide sunscreen page).
Hybrid organic filters – iron oxides
Organic filters from Annex VII give a thinner texture, iron oxides give the color. On in vitro plates, blue light (415–455 nm) blocking by commercial tinted sunscreens varied with the formula: creams with iron oxides plus both zinc oxide and titanium dioxide blocked more than darker-tinted creams with organic filters or hybrids with only one mineral filter (Dumbuya et al., 2026; 2 of 3 authors from industry). Each filter under its own entry; a photostability test; a hybrid version is not labeled "mineral filters only".
Packaging is planned with the formula
Multilayer tubes or pump bottles; checks for pigment settling, color separation, oil separation at the tube neck and plastic compatibility. No sprays or loose powders: Ref A29, A29a, 27a and Annex III Ref 338 (point c) exclude applications that may lead to inhalation into the lungs.
Parameters we monitor
What our R&D team measures on every sample
Below are the parameters Butter-C monitors during formula development and scale-up to production. Specific limits are agreed with you on the approved sample and then written into the product's in-house specification.
- SPF for each shade
- The labeled value is measured on people under ISO 24444:2019 at a laboratory whose ISO/IEC 17025 accreditation covers this method; in vitro screening results are used only during formula development.
- UVA protection
- Measured under ISO 24443:2021 (UVA protection factor, critical wavelength); the UVA symbol on the label follows the rules of the target market, since the ASEAN sunscreen labeling guideline does not set a specific symbol.
- Visible light (if a claim is wanted)
- There are no regulatory guidelines yet for assessing protection against blue light (Dumbuya, 2026); the test method, wavelength range and laboratory are agreed at the start and recorded in the dossier.
- Color
- Each lot color-matched to the reference sample with a colorimeter and under standard lighting; checks for color shift and pigment flotation after stability testing.
- Heavy metals
- COA of each iron oxide lot (arsenic, lead, mercury; nickel depending on positioning); finished product: mercury ≤ 1 ppm, arsenic ≤ 5 ppm, lead ≤ 20 ppm (Appendix 06-MP), cadmium ≤ 5 ppm (ASEAN guideline).
- Filter content
- Zinc oxide and titanium dioxide per formula, each with regular plus nano forms not exceeding 25%; COA of each powder lot (particle size, coating, nano form if any).
- Dispersion and stability
- Centrifugation, freeze–thaw cycling, storage at 40 °C; monitoring for pigment settling, oil separation and lumps; agglomerates checked under the microscope.
- Microbiology & preservative challenge
- Tested at a GLP / ISO 17025-accredited laboratory; preservative efficacy test under ISO 11930.
Claims
Writing claims within the cosmetic scope
Every number on a sunscreen label must be backed by a test report on the finished product itself, for that shade. The study in people with melasma (Castanedo-Cazares, 2014: 68 people, all also using 4% hydroquinone, a drug) is a medical setting and not a basis for claims about melasma. Wording follows the ASEAN sunscreen labeling guideline; Butter-C reviews the wording on the label and in marketing materials when preparing the notification dossier.
Helps protect skin against UVB; "broad spectrum" and "UVA protection" only once UVA has been measured on the finished product
Instead of: blocks UV completely, total sun protection, "sunblock".
SPF and PA according to the test result for each shade; SPF above 50 labeled "SPF 50+"
Instead of: values calculated from the ingredient list, one test result applied to all shades without acceptance.
Adds color, light coverage, helps skin look more even instantly
Instead of: skin whitening, fading dark spots, statements that iron oxides act on skin pigmentation.
Helps protect skin against visible light — only once tested on the finished product and approved by regulatory affairs
Instead of: "protects against blue light from screens", blocks blue light completely, statements inferred just from the presence of iron oxides.
Apply enough before sun exposure, reapply after sweating, swimming or toweling
Instead of: all-day protection, no need to reapply. Our iron oxide article notes that applying a thin layer like a foundation gives less protection than the labeled value.
Mandatory label warning
"Do not stay too long in the sun, even while using a sunscreen product" (Annex VII, for primary sunscreen products) — printed in the equivalent Vietnamese, with the translation approved by regulatory affairs.
Try on a small area of skin first; people with nickel allergy and pregnant women should ask a doctor if in doubt
Instead of: hypoallergenic, "free of heavy metals", completely safe for children and pregnant women. The product is not positioned for children; allergy to iron oxides is rare, but cases have been reported (our iron oxide article).
Manufacturing specifications
Current capabilities
- Texture
- Tinted sunscreen cream or lotion, light to medium coverage; one shade or several.
- Pack formats
- Tubes, pump bottles. No sprays or powders. Volume agreed when packaging is selected.
- Minimum order quantity
- Agreed per order — depends on the formula direction, the number of shades and the pack format chosen.
- Testing
- Quality parameters and heavy metals tested at a GLP / ISO 17025-accredited laboratory; SPF and UVA measured for each shade at a specialized testing facility.
- Dossier
- Product Information File (PIF) with SPF and UVA reports per shade, COAs of the filters and iron oxides, and the nanomaterial dossier when a nano form is used; notification dossier prepared by Butter-C.
- Labeling of colorants
- Under Circular 06/2011/TT-BYT (Article 5 as amended by Circular 34/2025/TT-BYT), colorants are listed by CI number or by their Annex IV name; whether a multi-shade range may use "may contain" or "+/-" is confirmed by regulatory affairs, since this provision is written for makeup products.
Suggested product concept
Tinted mineral sunscreen in three shades
A product concept to help you picture the possibilities, not a ready-made product for sale. The actual formula is developed to match your brand positioning and price range.
Coated zinc oxide – titanium dioxide
Mineral filters, non-nano particles; each substance within its own Annex VII entry, with levels set by the SPF measured on the finished product.
Red, yellow and black iron oxides
Blended into light, medium and deep shades; each shade has its own color reference and its own SPF test.
Antioxidant in the base
Tocopherol protects the oils; product D in the Ezekwe (2024) study also contained antioxidants — that result belongs to that formula.
40 ml tube
Water-in-oil emulsion, fragrance-free; the label carries the mandatory sunscreen warning and directions to apply enough and reapply.
Customization options
What you can specify
The same product type can serve very different customer groups depending on the brand. Tell us your requirements in the areas below and our team of pharmacists will develop a matching formula.
Number of shades
One easy-blending shade or a range — each shade is a separate formula, color reference and test.
Filter system
Mineral-only (zinc oxide, titanium dioxide) or hybrid with organic filters; this decides whether "mineral filters only" can be written.
Coverage
Sheer skin-tone matching or medium coverage replacing foundation — pigment load and skin feel change accordingly.
Target values
Desired SPF and UVA level — the final number follows the test result for each shade.
Visible light claim
Whether you want this statement — if so, the extra test and its cost are planned from the start.
Target market
Domestic only or export — the list of permitted filters, how colorants and nano forms are labeled and the UVA symbol differ from country to country.
Further reading
Related topics
Iron oxides in cosmetics
The three CI numbers, visible light data, metal impurities, allergy and ASEAN Annex IV (in Vietnamese).
Facial sunscreen manufacturing
The three filter systems — organic, inorganic and hybrid — for sunscreens in general.
Zinc oxide sunscreen manufacturing
Broad mineral UV filter, white cast and the nano dossier.
Titanium dioxide sunscreen manufacturing
Coatings that reduce photocatalysis, nano and powder conditions.
Skincare primer manufacturing
A tinted line without a sun protection claim, with the same shade-matching task.
UVA, UVB and visible light
How the different light ranges affect the skin (in Vietnamese).
How we work
From idea to finished batch
Eight steps and three milestones signed off by both sides: approved sample, notification number, finished batch. Step-by-step details →
Get started
Tell us about the product you plan to launch
Send us your product direction and expected volume. Our team will get back to you during business hours (Vietnam time, GMT+7).
Head office: Huu Le village, Dai Thanh commune, Hanoi · Factory: Thanh Oai Industrial Cluster, Binh Minh commune, Hanoi, Vietnam
Hotline +84 967 176 511 · [email protected] · Privacy policy ← Full catalog