What does 4-Butylresorcinol do?#
This serum uses resorcinol-based brightening compounds (such as 4-butylresorcinol) that work at very low concentrations to help visibly reduce the appearance of dark spots and uneven skin tone.
Benefits
- Helps visibly reduce the appearance of stubborn dark spots and patches
- Works at very low concentrations, which helps keep it gentle on skin
- Helps promote a more uniform, even-looking skin tone
- Helps deliver visible improvements in the look of skin tone with consistent use
How it works
Resorcinol-based brightening compounds are a targeted class of cosmetic ingredients used to even out the look of skin tone. They are designed to deliver visible results at very low concentrations, which helps reduce the likelihood of irritation while still providing noticeable improvements in skin tone evenness. They are valued for helping to reduce the appearance of stubborn dark spots and promote a more uniform-looking complexion.
How to use 4-Butylresorcinol#
Before you start
Patch test first if you react easily to new products, and stop using it if irritation or a rash appears.
Best time
It suits either, and both if you like.
How often
From the start is fine — it does not need weeks of easing in.
Where it goes
After cleansing, before moisturizer.
Where to apply
Across the whole area you want to even out, or just on the spots themselves. Keep it away from the eye area.
Sun
Wear sunscreen daily. 4-butylresorcinol isn't one of the actives we flag for extra sun care - and sun exposure is what drives the look of the marks you're working on, so daily protection earns its place either way.
What to expect
Give it time, and keep going. Any change in how dark spots look builds over several weeks, and it eases back if you stop — so it works better as a habit than as a course.
If it doesn't suit
Most people notice nothing unusual early on. A few see mild redness, itching or a little flaking in the first weeks — if that happens, drop back to once a day or every other day until it settles, which it usually does within the first month.
Discontinue use if irritation or a rash occurs. Patch test first if you react easily to new products.
The form you will see it in
Dark spot correcting serum
- Where it goes
- Before moisturizer
Using 4-Butylresorcinol with other ingredients
Pairs well with 4-Butylresorcinol
Niacinamide
Works well togetherComplementary brightening support — together they help promote a more even, radiant-looking complexion from two different angles.
Tranexamic acid
Works well togetherTogether they support a more even-looking complexion and help soften the look of dark spots.
What not to use with 4-Butylresorcinol
Nothing flagged. None of the ingredients this wiki covers needs to be kept apart from 4-Butylresorcinol — check the label of anything not covered here.
Who should avoid 4-Butylresorcinol?#
Six situations change whether 4-Butylresorcinol suits your skin right now. Each one is either a reason to skip it, a reason to go slowly, or nothing to watch for.
- Recent Facial or Laser
- Skip it
- Maternity & Nursing
- Go slowly
- Fragile or Sensitive
- Go slowly
- Prone to Redness
- Go slowly
- Dry or Itchy Patches
- Go slowly
- Recent Shave or Wax
- Go slowly
Maternity & Nursing — If you are pregnant or nursing, you may prefer to check with your healthcare provider before use.
Fragile or Sensitive — Use it less often — or stop — if it feels uncomfortable, and keep it off skin that’s broken, cut or sunburned.
Prone to Redness — Try it on a small area first, and use it less often — or stop — if you notice stinging or extra redness.
Dry or Itchy Patches — Keep the rest of your routine well moisturized, and use it less often — or stop — if you notice tightness or itching.
Recent Shave or Wax — Avoid for 24 hours after waxing, threading, or dermaplaning.
Cosmetic strength limits for 4-Butylresorcinol where you live#
| Region | Most a cosmetic may contain | |
|---|---|---|
 United States | No explicit cap | |
The FDA restricts a short list of ingredients and sets no general strength ceiling on the rest. A figure marked "guidance, not law" is the Cosmetic Ingredient Review panel's recommendation. 21 CFR part 700, subpart B — Requirements for Specific Cosmetic Products (FDA) | ||
 Canada | No explicit cap | |
One list does the work — Health Canada's Hotlist of prohibited and restricted cosmetic ingredients. | ||
 European Union | No explicit cap | |
The Cosmetics Regulation's annexes, consolidated to 1 May 2026. A figure marked "guidance, not law" comes from the EU's cosmetic safety committee rather than from the annexes. | ||
 Great Britain | No explicit cap | |
Great Britain kept the annexes as its own law and updates them only when it chooses; Northern Ireland follows the live EU Regulation, which is why some rows read differently for each. Regulation (EC) No 1223/2009 as it applies in Great Britain · Regulation (EC) No 1223/2009, Annexes II–VI | ||
 India | No explicit cap | |
India writes its own standard, aligned to the European rules as they stood in 2012. Mandatory since 9 February 2026. IS 4707 (Part 2):2025 — restricted and prohibited cosmetic ingredients · IS 4707 (Part 3):2025 — preservatives · Cosmetics Rules, 2020, Ninth Schedule | ||
 Brazil | No explicit cap | |
ANVISA rewrote its restricted list in June 2026, and a companion act amended the prohibited list at the same time. RDC 1.029/2026 — restricted ingredients · RDC 529/2021 — prohibited ingredients, as amended by RDC 1.030/2026 · RDC 528/2021 — preservatives | ||
 Japan | No explicit cap | |
Japan's cosmetics standard keeps drug ingredients out of cosmetics, so most of its figures sit in the ministry's list of the ones a cosmetic may still contain. Cosmetics Standards (化粧品基準), Ministry of Health, Labour and Welfare · Cosmetics Standards — the ministry's own English translation · Drug ingredients permitted in cosmetics — 2007 notification | ||
 South Korea | No explicit cap | |
One MFDS regulation carries both the prohibited list and the restricted list, in force 18 March 2026. Sunscreens and a few other categories are cleared product by product instead. Regulation on Safety Standards for Cosmetics (MFDS Notification 2026-19) · Regulation on the Review of Functional Cosmetics (MFDS Notification 2025-88) | ||
 Kenya | No explicit cap | |
Kenya's standard applies the EU annexes as they stand rather than copying them, so its ingredient limits are the EU's — including the 2024 additions. A figure marked "guidance, not law" sits outside the annexes and does not carry over. KS EAS 377-1, -2 and -3:2022 — cosmetics safety requirements, published by KEBS · Regulation (EC) No 1223/2009, Annexes II–VI | ||
 Namibia | No explicit cap | |
Namibia sets no ingredient limits at all. Its cosmetic rule is a single line requiring a product to be free of any harmful ingredient. Foodstuffs, Cosmetics and Disinfectants Ordinance 18 of 1979, and the regulations under it | ||
 Ukraine | No explicit cap | |
Ukraine's own transposition of the EU annexes, as they stood before the 2024 additions, fully in force since 3 August 2026. A further revision is due on 1 February 2027. Technical Regulation on cosmetic products — Cabinet Resolution No. 65 of 20 January 2021 | ||
 Georgia | No explicit cap | |
Georgia has no cosmetics rulebook — its register of technical regulations carries no cosmetics entry — so only the general product-safety duty applies. | ||
 Australia | No explicit cap | |
Australia writes no cosmetic ingredient list. A figure here is the point at which a substance becomes a medicine or a scheduled substance carrying Caution labeling, so its numbers sit well above other markets'. Poisons Standard — June 2026 · Therapeutic Goods (Excluded Goods) Determination 2018 | ||
 United Arab Emirates | No explicit cap | |
The Gulf standard points at the EU annexes as amended, so its ingredient limits are the EU's. A figure marked "guidance, not law" sits outside the annexes and does not carry over. GSO 1943:2024 — Cosmetic products: safety requirements (Gulf technical regulation) · Regulation (EC) No 1223/2009, Annexes II–VI | ||
 Kuwait | No explicit cap | |
The Gulf standard points at the EU annexes as amended, so its ingredient limits are the EU's. A figure marked "guidance, not law" sits outside the annexes and does not carry over. GSO 1943:2024 — Cosmetic products: safety requirements (Gulf technical regulation) · Regulation (EC) No 1223/2009, Annexes II–VI | ||
 Hong Kong | No explicit cap | |
Hong Kong writes no cosmetics rulebook. Its Poisons List (Cap. 138A, Schedule 10) decides which substances may be sold only as medicines, and general safety is judged case by case against whichever overseas standard the enforcer considers reasonable. Pharmacy and Poisons Regulations (Cap. 138A), Schedule 10 — the poisons list · Pharmacy and Poisons Board — Guidance Notes on classifying pharmaceutical products, April 2026 | ||
 Singapore | No explicit cap | |
Singapore writes the ASEAN annexes into its own schedule, and its regulator tells companies to check the current ASEAN release as well — which is why a figure here can read "guidance, not law". Health Products (Cosmetic Products — ASEAN Cosmetic Directive) Regulations 2007, Third Schedule · ASEAN Cosmetic Directive annexes — release 2026-1, 22 June 2026 | ||
 Brunei | No explicit cap | |
Brunei carries the 2007 ASEAN annexes in its own schedule and has not updated them since, so it reads differently from Singapore on several ingredients. Medicines (Cosmetic Products) Regulations (Cap. 285 Rg 1), Schedule 1 — revised edition 2024 | ||
 Jordan | No explicit cap | |
Jordan's cosmetic rules defer to "the approved references" and name none of them, so there is no Jordanian figure to read. The only number in the instrument governs the ingredient list on the pack. JFDA instructions on cosmetics and pharmaceutical cosmetics, 2026 | ||
 Trinidad & Tobago | No explicit cap | |
Trinidad and Tobago has had the power to set cosmetic standards since 1960 and has never used it. The regulations made under the Act cover food and drugs, with no cosmetics part; what binds is the Act's general rule against selling a cosmetic that may injure the user. Food and Drugs Act, Chap. 30:01 · Food and Drugs Regulations | ||
No cosmetic regulator in the 20 markets above sets a maximum strength for 4-butylresorcinol. That is the state of the rules, not a signal to use more: how much goes into a product is the formulator's decision.
Open a market to see the rulebook its figure comes from. Those notes describe each market's own rules as we read them, current to August 24, 2026; the linked documents are the authority, and nothing here is legal advice.
Sample products with 4-Butylresorcinol#
A few well-known products, not a full list — product names are each brand's own. We don't sell them — the shop prices them in US dollars and ships from Hong Kong, so delivery and duties come on top. It may not ship everywhere.
We may earn a small commission when you buy through these links.
Already have one? Check how it fits your skin with Pick.
Common questions about 4-Butylresorcinol#
What is 4-Butylresorcinol?
- A targeted brightening ingredient that helps stubborn dark spots and uneven patches look lighter, for a more even-looking complexion.
What else is 4-Butylresorcinol called?
- On a label you may see Butylresorcinol and Rucinol.
When should you apply 4-Butylresorcinol?
- Morning or evening. It suits either, and both if you like.
How often can you use 4-Butylresorcinol?
- Daily, all over the face, not the eye area.
Where do you apply 4-Butylresorcinol?
- All over the face, not the eye area. Keep it off your lips too.
Can you use 4-Butylresorcinol around the eyes?
- No. 4-Butylresorcinol goes all over the face, not the eye area.
Does 4-Butylresorcinol make skin more sensitive to the sun?
- No. 4-Butylresorcinol is not flagged as increasing sun sensitivity.
What should you not use with 4-Butylresorcinol?
- Nothing flagged. None of the ingredients this wiki covers needs to be kept apart from 4-Butylresorcinol — check the label of anything not covered here.
Who should avoid 4-Butylresorcinol?
- Skip it if any of these apply: Recent Facial or Laser. Go slowly with Maternity & Nursing, Fragile or Sensitive, Prone to Redness, Dry or Itchy Patches and Recent Shave or Wax.
Is there a cosmetic limit for 4-Butylresorcinol?
- No. No cosmetic regulator in the United States, Canada, the European Union or Great Britain sets a maximum strength for it. That is a limit on the rules, not a signal to use more.
Related ingredients#
How we check this#
Everything on this page traces to the sources listed below — regulators' own publications and published studies. Where the evidence does not answer a question, it is left unanswered.
Some sources below are the official product information for prescription medicines, cited for how they interact with this ingredient. We use them for their safety and handling detail only. A cosmetic product is not one of those medicines and is not intended to treat any condition.
Our review is AI-assisted and is not a named expert's opinion. Last reviewed August 6, 2026.
Think something here is out of date or wrong? Email us at wiki@skinintelligence.ai with your reasoning and where you read it. We read what people send, and we update the page when the sources support it.
Regulators and official bodies · 10
- S21Roaccutane 10 mg soft capsules — Summary of Product Characteristics, sections 4.4 and 4.5. medicines.org.uk/emc/product/100633/smpc.
- S23Treclin 1%/0.025% w/w Gel — Summary of Product Characteristics, section 4.5. medicines.org.uk/emc/product/5371/smpc.
- S25Regulation (EC) No 1223/2009 on cosmetic products, consolidated text CELEX 02009R1223-20260501 (Annexes I–X). eur-lex.europa.eu.
- S26CosIng ingredient record, 4-BUTYLRESORCINOL, CAS 18979-61-8. ec.europa.eu/growth/tools-databases/cosing/details/54209.
- S27Cosmetic Products Regulation (assimilated), Annex III. legislation.gov.uk/eur/2009/1223/annex/III.
- S28FDA, Prohibited & Restricted Ingredients in Cosmetics (21 CFR 700 series). fda.gov/cosmetics/cosmetics-laws-regulations/prohibited-restricted-ingredients-cosmetics.
- S2921 CFR 333.310(b),(c),(f) and 333.320 — OTC topical acne drug products. ecfr.gov.
- S30Health Canada, Cosmetic Ingredient Hotlist.
- S31Commission Regulation (EU) 2024/996, recitals 5–6 and 14. eur-lex.europa.eu/eli/reg/2024/996/oj.
- S32Tretinoin gel/cream, US label, Drug Interactions. DailyMed setid 4889c7f8-37d0-4f1a-9829-bca107806586; and RETIN-A label, accessdata.fda.gov/drugsatfda_docs/label/2002/16921s21s22s25lbl.pdf.
Studies and references · 22
- S1Kolbe L, Mann T, Gerwat W, Batzer J, Ahlheit S, Scherner C, Wenck H, Stäb F. 4-n-butylresorcinol, a highly effective tyrosinase inhibitor for the topical treatment of hyperpigmentation. J Eur Acad Dermatol Venereol 2013;27 Suppl 1:19–23. PMID 23205541.
- S2Huh SY, Shin JW, Na JI, Huh CH, Youn SW, Park KC. The efficacy and safety of 4-n-butylresorcinol 0.1% cream for the treatment of melasma: a randomized controlled split-face trial. Ann Dermatol 2010;22(1):21–5. PMID 20548876 / PMC2883392.
- S3Khemis A, Kaiafa A, Queille-Roussel C, Duteil L, Ortonne JP. Evaluation of efficacy and safety of rucinol serum in patients with melasma: a randomized controlled trial. Br J Dermatol 2007;156(5):997–1004. PMID 17388924.
- S4Madan Mohan NT, Gowda A, Jaiswal AK, Sharath Kumar BC, Shilpashree P, Gangaboraiah B, Shamanna M. Assessment of efficacy, safety, and tolerability of 4-n-butylresorcinol 0.3% cream: an Indian multicentric study on melasma. Clin Cosmet Investig Dermatol 2016;9:21–7. PMID 26855596 / PMC4725640.
- S5Lapeere H, De Keyser E. Allergic contact dermatitis caused by 4-n-butylresorcinol present in a night cream for skin hyperpigmentation. Contact Dermatitis 2020;83(2):134–5. PMID 32243593.
- S6Kim S, Yang H, Kim M, Baek JH, Kim SJ, An SM, Koh JS, Seo R, Jung H. 4-n-butylresorcinol dissolving microneedle patch for skin depigmentation: a randomized, double-blind, placebo-controlled trial. J Cosmet Dermatol 2016;15(1):16–23. PMID 26341915.
- S7Furmanczyk M, Brown A, Bustos J, de Henestrosa ARF, Trullas C, Granger C, Jourdan E. Efficacy and tolerability of a depigmenting gel serum comprising tranexamic acid, niacinamide, 4-butylresorcinol, phytic acid, and a mixture of hydroxy acids… J Cosmet Dermatol 2024;23(6):2058–65. PMID 38549196.
- S8Cantelli M, Ferrillo M, Granger C, Fabbrocini G. An open-label… pilot clinical study to evaluate the efficacy of a skin whitening serum applied twice daily combined with a spot-preventing SPF50+ sunscreen… J Cosmet Dermatol 2022;21(4):1544–51. PMID 34087055.
- S9Kwon SH, Yang JH, Shin JW, Park KC, Huh CH, Na JI. Efficacy of liposome-encapsulated 4-n-butylresorcinol and resveratrol cream in the treatment of melasma. J Cosmet Dermatol 2020;19(4):891–5. PMID 31347777.
- S10Nishimaki-Mogami T, Ito S, Cui H, Akiyama T, Tamehiro N, Adachi R, Wakamatsu K, Ikarashi Y, Kondo K. A cell-based evaluation of human tyrosinase-mediated metabolic activation of leukoderma-inducing phenolic compounds. J Dermatol Sci 2022;108(2):77–86. PMID 36567223.
- S11Ito S, Wakamatsu K. A convenient screening method to differentiate phenolic skin whitening tyrosinase inhibitors from leukoderma-inducing phenols. J Dermatol Sci 2015;80(1):18–24. PMID 26228294.
- S12Maeda K. Timeline of the development of skin-lightening active ingredients in Japan. Molecules 2022;27(15):4774. PMID 35897958.
- S13Austin E, Nguyen JK, Jagdeo J. Topical treatments for melasma: a systematic review of randomized controlled trials. J Drugs Dermatol 2019;18(11):1156–71. PMID 31741361.
- S14Liu Y, Ni H, Wargniez W, Grégoire S, Durand I, Roussel-Berlier L, Eilstein J, Jie Q, Ma T, Shen T, Wang Y, Qiu J. Inter-laboratory study of the skin distribution of 4-n-butyl resorcinol in ex vivo pig and human skin. J Chromatogr B 2018;1093-1094:77–9. PMID 29990716.
- S15Garcia-Jimenez A, Teruel-Puche JA, Ortiz-Ruiz CV, Berna J, Tudela J, Garcia-Canovas F. 4-n-butylresorcinol, a depigmenting agent used in cosmetics, reacts with tyrosinase. IUBMB Life 2016;68(8):663–72. PMID 27342394.
- S16Mota S, Rosa GP, Barreto MC, Garrido J, Sousa E, Cruz MT, Almeida IF, Quintas C. Comparative studies on the photoreactivity, efficacy, and safety of depigmenting agents. Pharmaceuticals (Basel) 2023;17(1):32. PMID 38256889 / PMC10820089.
- S17Ren H, Yin M, Li X, Zhang F, et al. Enhanced stability and reduced irritation of 4-n-butylresorcinol via nanoemulsion formulation: implications for skin pigmentation treatment. Eur J Med Chem 2024;279:116867. PMID 39326268.
- S18Grippaudo FR, Di Russo PP. Effects of topical application of B-Resorcinol and glycyrrhetinic acid monotherapy and in combination with fractional CO2 laser treatment for benign hand hyperpigmentation treatment. J Cosmet Dermatol 2016;15(4):413–9. PMID 27325103.
- S19Fabbrocini G, De Vita V, Fardella N, Pastore F, Annunziata MC, Mauriello MC, Monfrecola A, Cameli N. Skin needling to enhance depigmenting serum penetration in the treatment of melasma. Plast Surg Int 2011;2011:158241. PMID 22567235 / PMC3335478.
- S20Zhang T, Wang Y, Xu Y, Liu Y, Zhuang B, Zhang X, Liao C, Liu W, Ma Y. Enhanced whitening effect of the formulations via inhibition of tyrosinase activity by combination of 4-n-butylresorcinol, licochalcone A and glabridin at an optimal ratio. Skin Res Technol 2026;32(3). PMID 41853874.
- S22Mann T, Gerwat W, Batzer J, Eggers K, Scherner C, Wenck H, Stäb F, Hearing VJ, Röhm KH, Kolbe L. Inhibition of human tyrosinase requires molecular motifs distinctively different from mushroom tyrosinase. J Invest Dermatol 2018;138(7):1601–8. PMID 29427586.
- S24Lee CS, Joo YH, Baek HS, Park M, Kim JH, Shin HJ, Park NH, Lee JH, Park YH, Shin SS, Lee HK. Different effects of five depigmentary compounds, rhododendrol, raspberry ketone, monobenzone, rucinol and AP736 on melanogenesis and viability of human epidermal melanocytes. Exp Dermatol 2016;25(1):44–9. PMID 26440747.
