4-Butylresorcinol

4-Butylresorcinol (Purity ≥99.0%-99.5% HPLC / Rucinol Grade / Nano-Liposomal Options) | Gold Standard Dual-Enzyme Active for Human Tyrosinase & TRP-1 Inhibition, Melasma Clearance & Spot Erasure

1. Product Overview & Value Proposition

4-Butylresorcinol (4-butylbenzene-1,3-diol, commercially designated as Rucinol, 4-丁基间苯二酚), engineered by introducing a four-carbon linear aliphatic butyl tail onto the 4-position of a resorcinol ring, represents one of the most pharmacologically precise and clinically verified depigmenting bioactives in aesthetic dermatology. While traditional skin-lightening ingredients (such as arbutin, kojic acid, or ascorbic acid derivatives) target only the primary tyrosinase enzyme, 4-Butylresorcinol delivers a specialized dual-enzyme inhibitory mechanism: it directly blocks both Tyrosinase (monophenolase and diphenolase catalytic cycles) and Tyrosinase-Related Protein-1 (TRP-1). This coordinated dual action suppresses the entire enzymatic pathway of eumelanin synthesis, preventing the conversion of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into dark, insoluble melanin polymers.

In comparative clinical biochemistry, 4-Butylresorcinol demonstrates superior binding affinity for the binuclear copper catalytic pocket of human tyrosinase. In enzymatic assays using purified human tyrosinase (rather than non-human mushroom tyrosinase), 4-Butylresorcinol exhibited an IC50 of approximately 11.27 μmol/L, significantly outperforming hydroquinone, arbutin, and kojic acid. More importantly, it achieves this profound melanin clearance at low concentrations (typically 0.1% to 0.3%) without inducing melanocyte apoptosis, cytotoxicity, or the permanent cellular destruction linked to prescription hydroquinone. It is widely recognized as a benchmark topical active for stubborn facial melasma (chloasma), post-inflammatory hyperpigmentation (PIH), age spots (solar lentigines), and procedural hyperpigmentation following laser resurfacing. We provide specialized commercial grades tailored to cosmetic and dermatological manufacturing requirements:

• Ultra-Pure Clinical Crystalline Powder (≥ 99.0% & 99.5% HPLC): Snow-white microcrystalline powder with residual resorcinol controlled below 0.05%, engineered for prestige spot-correcting serums, medical-grade depigmentation creams, and dermatological night balms.
• Cold-Water-Dispersible (CWD) Nano-Liposomal & Liquid Dispersions (5.0%–10.0%): Pre-solubilized, phospholipid-encapsulated nano-emulsions utilizing hydrogenated lecithin. Bypasses the lipophilic solubility barrier of raw crystals, enabling transparent, cold-process integration into facial toners, essence waters, and post-procedure sheet masks without crystallization or turbidity.
• Stabilized Anti-Discoloration Systems: Low-melting crystals (~52°C) engineered for rapid, gentle incorporation into cosmetic oil phases, displaying high resistance to pink/red oxidative discoloration when paired with chelators and antioxidant stabilizers.

As an established bulk 4-Butylresorcinol manufacturer and direct active ingredient supplier, our facilities operate continuous catalytic alkylation suites, automated macroporous resin chromatography lines, and low-temperature vacuum crystallization systems. To empower agile skincare brands, cosmetic chemists, and contract manufacturing organizations (CMOs), we pair uncompromising analytical quality with flexible commercial terms: accessible low MOQ procurement for benchtop pilot trials, multi-ingredient shipment consolidation across our cosmetic bioactives (Phenylethyl Resorcinol 377, Alpha-Arbutin, Glabridin, Ferulic Acid, Phloretin, Ceramide NP, Madecassoside, Bakuchiol), and dedicated on-the-ground China-wide raw material sourcing assistance tailored to your exact manufacturing roadmap.

2. Product Specifications (Analytical Quality)

3. Functional Applications (Mechanism of Action)

Deploying pharmaceutical-grade 4-Butylresorcinol across clinical brightening serums, targeted melasma treatments, and post-procedure spot correctors provides scientifically verified cellular actions:

• Dual Enzymatic Blockade of Human Tyrosinase & TRP-1: 4-Butylresorcinol binds competitively to the binuclear copper active site of human tyrosinase, blocking the enzymatic conversion of L-tyrosine into L-DOPA and dopaquinone. Concurrently, it uniquely inhibits Tyrosinase-Related Protein-1 (TRP-1), an essential melanosomal enzyme that catalyzes the oxidation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into dark eumelanin. By neutralizing both enzymatic checkpoints simultaneously, it suppresses pigment synthesis more comprehensively than single-pathway tyrosinase inhibitors.
• High Specificity on Human vs. Mushroom Tyrosinase: In clinical cosmetic pharmacology, many conventional actives (like kojic acid and arbutin) display high potency against fungal/mushroom tyrosinase but exhibit diminished affinity for human tyrosinase. In contrast, 4-Butylresorcinol exhibits exceptional stereospecific affinity for human tyrosinase (IC50 ~11.27 μmol/L), demonstrating clinical depigmentation in human in vivo cohorts at concentrations as low as 0.05% to 0.3%.
• Non-Cytotoxic, Reversible Safety Profile: Prescription depigmenting drugs (such as hydroquinone) clear hyperpigmentation by inducing severe oxidative stress that kills melanocytes (cytotoxicity), carrying severe risks of permanent confetti leukoderma and exogenous ochronosis. 4-Butylresorcinol blocks melanin synthesis via reversible enzymatic competition without damaging melanocyte structural integrity or decreasing cellular viability, ensuring high dermatological safety for long-term daily maintenance.
• Clinical Superiority in Refractory Melasma (Chloasma): Hormonally triggered facial melasma is notoriously resistant to standard cosmetic treatment due to deep dermal and epidermal pigment distribution. Multiple randomized, double-blind, vehicle-controlled clinical trials confirm that topical 0.1% to 0.3% 4-Butylresorcinol produces statistically significant improvements in Melasma Area and Severity Index (MASI) scores within 8 to 12 weeks, outperforming hydroquinone 4% formulations with significantly less irritation, erythema, or peeling.
• Optimal Membrane Permeability & Melanosomal Uptake: The 4-carbon linear alkyl tail provides an optimal lipophilicity balance (logP ~2.6). This allows 4-Butylresorcinol to partition smoothly through stratum corneum lipid bilayers, enter epidermal keratinocytes and basal melanocytes, and concentrate directly inside the inner melanosomal lumen where active melanogenesis takes place.
• Formulation Stability & Low Melting Point Ease: With a melting point around 51°C–55°C, 4-Butylresorcinol melts easily into the cosmetic oil phase or glycol premixes during low-temperature emulsion compounding (<60°C). When maintained within an acidic-to-neutral pH window (pH 4.5 to 6.0) alongside chelating agents and water-soluble antioxidants, it resists pink/red oxidative discoloration throughout long-term shelf-life cycles.

4. Formulation Combinations & Trending Market Applications

Capitalize on the expanding clinical spot-correction, aesthetic dermatological, and high-efficacy cosmeceutical markets by formulating with our versatile 4-Butylresorcinol portfolio:

• The Master Clinical “Melasma & Stubborn Spot Eraser” Serum: Our 4-Butylresorcinol (≥99.5%, 0.2%–0.3%) + Tranexamic Acid (USP, 2.0%–3.0%) + Niacinamide (≥99.5%, 4.0%–5.0%) + Ethyl Ascorbic Acid (Lipophilic Vitamin C, 2.0%) + Bisabolol (≥95%, 0.5%). The globally recognized benchmark melasma-correcting matrix: 4-Butylresorcinol blocks tyrosinase and TRP-1 enzymes, Tranexamic Acid suppresses plasmin-mediated melanocyte activation, Niacinamide prevents melanosome transfer, and Bisabolol calms underlying micro-inflammation.
• The “Post-Acne PIH & Blemish-Clarifying” Fluid: Our 4-Butylresorcinol (≥99.5%, 0.2%) + Azelaic Acid Derivative (Potassium Azeloyl Diglycinate, 3.0%) + Glabridin (CWS Water-Soluble 10%, 0.5% delivering 0.05% active) + Zinc PCA (1.0%) + Centella Asiatica Extract (Madecassoside ≥95%, 0.2%). A targeted clarifying emulsion designed to dissolve follicular blemishes, regulate sebum, soothe post-inflammatory erythema (PIE), and erase stubborn brown acne marks (PIH).
• The “Post-Laser & Barrier Repair” Night Balm: Our Nano-Liposomal 4-Butylresorcinol (5% Active, 4.0% delivering 0.2% active) + Ceramide NP (≥98%, 0.2%) + Madecassoside 95% (0.2%) + PDRN (Sodium DNA ≥98%, 0.2%) + Ectoine (≥99.0%, 1.0%). A soothing, restorative night treatment engineered for post-procedure recovery to clear procedural pigmentation, rebuild the intercellular lipid barrier, and accelerate dermal re-epithelialization without stinging.
• The High-Clarity “Radiant Tone” Essence Water: Our Water-Dispersible Nano-Liposomal 4-Butylresorcinol (10% Active, 2.0% delivering 0.2% active) + Alpha-Arbutin (≥99.5%, 1.0%) + Ectoine (1.0%) + Multi-Molecular Weight Sodium Hyaluronate (0.5%) + Propanediol (5.0%). A crystal-clear, refreshing aqueous essence designed to deliver rapid skin-tone brightening, deep cellular hydration, and environmental antioxidant protection without cloudiness or sticky residue.

5. Why Choose Us As Your Long-Term Active Ingredient Partner?

• Flexible Low MOQ Policy: Mitigate product launch risk. As an agile low MOQ 4-Butylresorcinol bulk supplier, our orders start as low as 100 g for ultra-pure prestige clinical grades (≥99.5%), 500 g for standard cosmetic grade (≥98.5%), and 1 kg for pre-dispersed nano-liposomal liquids (5%–10%), scaling smoothly up to recurring multi-hundred kilogram commercial manufacturing contracts.
• Strict Resorcinol Control (≤ 0.05%): Residual unreacted resorcinol is the primary source of skin irritation and regulatory non-compliance in resorcinol derivatives. Our multi-stage recrystallization process guarantees residual unreacted resorcinol remains strictly ≤ 0.05% (500 ppm), ensuring high tolerance in sensitive, rosacea-prone, and post-procedure skin.
• Multi-Product Portfolio Consolidation: Streamline your supply chain by sourcing your complete clinical brightening suite (4-Butylresorcinol, Phenylethyl Resorcinol 377, Alpha-Arbutin, Glabridin, Ferulic Acid, Phloretin, Ceramide NP, Madecassoside, Bakuchiol, Ectoine, L-Ergothioneine, PDRN), longevity vitamins (L-5-MTHF-Ca, β-NMN), and botanical extracts under a single, cost-effective freight shipment to reduce customs overhead and landed freight costs.
• Value-Added China Sourcing Service: In addition to our dedicated chemical synthesis lines, liposomal nano-homogenization facilities, and high-vacuum crystallization suites, our on-the-ground technical team audits upstream intermediate manufacturing, validates HPLC impurity profiling paperwork, and procures specialized functional ingredients across China tailored to your exact manufacturing roadmap.

6. Quality & Supply Chain Assurance

• Precision Catalytic Alkylation Synthesis: Produced via selective Friedel-Crafts alkylation of pure resorcinol using butanol or butyl halides. Our catalytic engineering suppresses dialkylated side-products (such as 4,6-dibutylresorcinol), which can alter melting points and cause batch haziness. High-vacuum recrystallization delivers pure, snow-white crystalline material.
• Advanced Solubilization & Anti-Discoloration Technology: 4-Butylresorcinol has a low melting point (~52°C) and sparingly dissolves in plain water (~1.5 g/L). We supply both pure crystalline powders for oil-phase/glycol compounding and pre-solubilized nano-liposomal grades (5%–10% active) that disperse transparently into room-temperature water without heating or crystal precipitation.
• Validated HPLC Analytical Standardization: Every commercial batch is tested against certified primary reference standards using High-Performance Liquid Chromatography (HPLC-UV at 280 nm). We quantify pure 4-Butylresorcinol, verify the absence of heavy-metal catalysts, and guarantee batch-to-batch active potency and color stability.
• Formulation Compatibility & Color Stability Protocols: High-purity 4-Butylresorcinol is pure white to off-white, preventing the initial formula yellowing caused by inferior grades. When formulated with chelators (disodium EDTA) and water-soluble antioxidants (such as sodium metabisulfite or sodium bisulfite at 0.1%–0.2%) within pH 4.5 to 6.0, it resists oxidative pink or brown discoloration over accelerated shelf-life cycles.
• Comprehensive ICP-MS & Heavy Metal Screening: Batch-tested via high-resolution ICP-MS to ensure heavy metals (Lead, Arsenic, Cadmium, Mercury) strictly comply with California Prop 65, European Cosmetic Regulation (EC) No 1223/2009, and China Safety and Technical Standards for Cosmetics. Sealed in food/pharma-grade double-polyethylene liners within light-proof aluminum bottles (100 g, 500 g, 1 kg) and heavy-duty 25 kg fiber export drums.

7. FAQ

Q1: What is the primary biological and clinical difference between 4-Butylresorcinol and Phenylethyl Resorcinol (377)?
A1: While both are resorcinol derivatives engineered for tyrosinase inhibition, their molecular structures and target profiles differ:

• 4-Butylresorcinol (Rucinol): Features a linear 4-carbon aliphatic butyl chain (MW: 166.22 g/mol; logP ~2.6). It exerts a dual-action blockade on both Tyrosinase and TRP-1. It displays exceptionally high affinity for human tyrosinase and is clinically favored for treating deep, diffuse hormonal melasma and stubborn facial pigmentation at low concentrations (0.1%–0.3%).
• Phenylethyl Resorcinol (377): Features an aromatic 1-phenylethyl group (MW: 214.26 g/mol; logP ~3.6). Inspired by the pine stilbene pinosylvin, it is more lipophilic and combines tyrosinase inhibition with potent antioxidant and lipid anti-peroxidation properties. Both rank among the most effective non-prescription depigmenting agents available.

Q2: Why is 4-Butylresorcinol considered a safer, non-cytotoxic alternative to Hydroquinone?
A2: Prescription hydroquinone functions primarily through cytotoxicity: it produces intracellular reactive oxygen species and quinone metabolites that destroy melanocyte organelles, carrying severe risks of permanent patchy leukoderma (confetti hypopigmentation) and exogenous ochronosis. In contrast, 4-Butylresorcinol acts as a competitive, reversible enzyme inhibitor. It blocks tyrosinase and TRP-1 catalytic sites without altering melanocyte viability or inducing cellular apoptosis, delivering clinical spot clearance with high long-term dermatological safety.

Q3: How do formulators dissolve crystalline 4-Butylresorcinol and prevent formula discoloration?
A3: With a melting point around 51°C–55°C, 4-Butylresorcinol is sparingly soluble in plain cold water (~1.5 g/L). Formulators incorporate it cleanly using three standard techniques:

• Low-Temperature Oil Phase Co-Melting: Gently melt the crystals into the cosmetic oil phase or polar emollients (C12-15 alkyl benzoate, caprylic/capric triglyceride) at 55°C–60°C prior to emulsification.
• Glycol Pre-Dissolution: Dissolve in cosmetic glycols (propanediol, 1,3-butylene glycol, propylene glycol) at room temperature or gentle warmth (~40°C), adding during the cool-down phase below 45°C.
• Anti-Discoloration Safeguards: Maintain formulation pH between 4.5 and 6.0, incorporate 0.05%–0.1% disodium EDTA or sodium phytate to sequester trace metals, add 0.1%–0.2% sodium metabisulfite or lipophilic antioxidants, and house the finished formula in opaque airless packaging.

Q4: What is the clinically supported usage percentage of 4-Butylresorcinol in finished cosmetic products?
A4: Formulating guidelines depend on the delivery format and target application:

• Clinical Melasma & Targeted Dark-Spot Correctors: 0.1% to 0.3% of pure 4-Butylresorcinol powder (clinically validated in human trials to significantly reduce MASI melasma scores).
• Daily Tone-Evening Serums & Lotions: 0.05% to 0.1%.
• Aqueous Toners & Clear Sheet Masks: 1.0% to 2.0% of our water-dispersible nano-liposomal 10% liquid (yielding 0.1%–0.2% active).
• Formulating Window: Optimal formulation pH is mildly acidic to neutral (pH 4.5 to 6.0); stable when added during the cool-down phase (<45°C).

Q5: What is the MOQ for bulk 4-Butylresorcinol orders?
A5: We support agile product commercialization with flexible minimum order quantities starting from just 100 g for ultra-pure prestige clinical crystals (≥99.5%), 500 g for standard cosmetic grade (≥98.5%), and 1 kg for pre-dispersed nano-liposomal liquids (5%–10%), scaling smoothly up to recurring multi-hundred kilogram commercial manufacturing contracts.

8. References

1. PubChem: 4-Butylresorcinol Compound Summary (CID 88185) – National Center for Biotechnology Information.
2. PubMed Central: 4-Butylresorcinol: A Highly Effective Dual Inhibitor of Human Tyrosinase and TRP-1 for the Clinical Treatment of Melasma and Hyperpigmentation – National Institutes of Health research database.

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