Caproic Acid (also known as hexanoic acid) is a medium-chain fatty acid that is naturally found in various animal fats and vegetable oils. It is characterized by its six-carbon chain and is commonly used in the cosmetic industry for its emollient and surfactant properties.
Caproic Acid plays a role in enhancing the texture and stability of formulations, making it a valuable ingredient in skin and hair care products. Additionally, it possesses antimicrobial properties, which can contribute to the preservation of cosmetic formulations. Its unique characteristics make Caproic Acid a versatile component in the development of effective and appealing personal care products.
CAS Number: 142-62-1
Molecular Formula: C6H12O2
Synonyms:
- sodium caproate
- bismuth(III)hexanoate
- hexanoic acid, copper (2+) salt
- hexanoate
- sodium hexanoate
- hexanoic acid, sodium salt
+ 15 more…
- Bi(OHex)3
- hexanoic acid, rhodium (2+) salt
- n-caproic acid
- hexanoic acid
- calcium hexanoate
- caproate
- capronic Acid
- hexanoic acid, potassium salt
- hexanoic acid, manganese (2+) salt
- hexanoic acid, sodium salt (1:1)
- hexanoic acid, calcium salt
- calcium N-hexanoate
- hexanoic acid, nickel (2+) salt
- hexanoic acid, barium salt
- caproic acid sodium salt
Properties of Caproic Acid
Chemical Identifiers
| EC Number | 205-550-7 |
| UNII | 1F8SN134MX |
| InChIKey | FUZZWVXGSFPDMH-UHFFFAOYSA-N |
| SMILES | CCCCCC(=O)O |
| IUPAC Name | hexanoic acid |
| InChI | InChI=1S/C6H12O2/c1-2-3-4-5-6(7)8/h2-5H2,1H3,(H,7,8) |
Physical and Chemical Properties
Caproic Acid is characterized by its white crystalline solid form or a colorless to pale yellow liquid state, accompanied by a strong and unpleasant odor. It exhibits limited solubility in water and has a density lower than that of water.
This compound can cause significant irritation upon contact with skin, eyes, and mucous membranes. Additionally, it poses toxicity risks through ingestion, inhalation, and dermal absorption. Caproic Acid is commonly utilized in the production of fragrances and perfumes.
| Property | Value |
| LogP | log Kow = 1.92 |
| Odor | Characteristic goat-like odor |
| Density | 0.927 – Less dense than water; will float |
| Viscosity | 3.23 mPa.s at 20°C |
| Color/Form | Oily liquid |
| Solubility | 5 to 10 mg/mL at 72°F |
| Flash Point | 220°F |
| Boiling Point | 396 to 397°F at 760 mmHg |
| Melting Point | 27°F |
| Decomposition | When heated to decomposition it emits acrid smoke and fumes. |
| Vapor Density | 4.01 – Heavier than air; will sink (Relative to Air) |
| Odor Threshold | Low: 6000.0 [mmHg] |
| Vapor Pressure | 0.2 mmHg at 68°F 1 mmHg at 158°F 20 mmHg at 233.2°F |
| Surface Tension | 23.4 mN/m at 70°C |
| Refractive Index | 1.4170 at 20 C/D |
| Heat of Combustion | -3,492.4 KJ/mol (liquid) |
| Henry’s Law Constant | 7.58X10-7 atm cu m/mol at 25°C |
| Dissociation Constants | pKa = 4.88 |
| Kovats Retention Index | 973 |
| Collision Cross Section | 128.54 Ų [M-H]- [CCS Type: DT; Method: single field calibrated with Agilent tune mix (Agilent)] |
| Autoignition Temperature | 716°F |
| Other Experimental Properties | Heat of formation: -584.0 KJ/mol Specific heat 2.33 J/g |
Structural Properties
Caproic Acid has a moderate complexity, with a simple structure consisting of eight atoms. It is a neutral molecule, meaning it has no formal charge. The compound has a moderate molecular weight and includes a few flexible bonds that can rotate. It can form hydrogen bonds, with one hydrogen donor and two acceptors.
Additionally, the compound has a topological polar surface area, indicating it is somewhat hydrophilic. The molecule is canonicalized, meaning it is represented in its most stable form. Overall, Caproic Acid’s structure suggests it is relatively simple and stable with moderate interactions.
| Property | Value |
| XLogP3 | 1.9 |
| Complexity | 68.9 |
| Exact Mass | 116.083729621 g/mol |
| Formal Charge | 0 |
| Heavy Atom Count | 8 |
| Molecular Weight | 116.16 g/mol |
| Monoisotopic Mass | 116.083729621 g/mol |
| Isotope Atom Count | 0 |
| Rotatable Bond Count | 4 |
| Compound Is Canonicalized | Yes |
| Hydrogen Bond Donor Count | 1 |
| Hydrogen Bond Acceptor Count | 2 |
| Covalently-Bonded Unit Count | 1 |
| Topological Polar Surface Area | 37.3 Ų |
| Defined Atom Stereocenter Count | 0 |
| Defined Bond Stereocenter Count | 0 |
| Undefined Atom Stereocenter Count | 0 |
| Undefined Bond Stereocenter Count | 0 |
Uses of Caproic Acid in Cosmetics
Functional role in cosmetics:
- Caproic Acid is used as a emulsifying agent in cosmetics.
Other uses:
- Used in lubricants and as a lubricant additive.
- Also used as a surfactant.
Cosmetic Products Containing Caproic Acid
Recent products using Caproic Acid in their cosmetic formulations
- NATURE SPELL Hyaluronic Acid Oil
- Ree Derma Hot Oil Hair And Scalp Treatment
- Snowberry Youth Renewing Serum With Eprolex™
- Skindose Ginseng Bee Venom
- Ultraceuticals Ultra C10+ Firming Serum
- Ryx Skin Sincerity Tokyo Luxe Bathe (beauty Milky Bar)
- Gigi Ester C Skin Whitening
- Luxmetique Unifique Serum
- Bio essence Bio Energy Complex Bio-Treasure Jeju Water Hydrating Skin Lotion
- Mary Kay Timewise 4-in-1 Cleanser (Normal To Oily)
- Hourglass Unreal Liquid Blush
- nuse Color Care Lipbalm
- Dr.Touchh Melasma 3d Serum Plus
- BEYOND Gold Mask 24k
- Marta Masi BB Cream
- O Skin Care Secret Gold 24k Night Mask
Top companies using Caproic Acid in their cosmetic products
- NATURE SPELL
- Ree Derma
- Snowberry
- Skindose
- Ultraceuticals
- Ryx Skin Sincerity
- Gigi
- Luxmetique
- Bio essence
- Mary Kay
- Hourglass
- nuse
- Dr.Touchh
- BEYOND
- Marta Masi
How Caproic Acid Works in Formulations
Caproic Acid is a versatile ingredient in cosmetics, prized for its antimicrobial, emollient, and skin-conditioning properties. It’s commonly found in skin care, hair care, and cleansing products, helping to hydrate, soothe, and improve product performance.
Ideal Concentration and Benefits in Different Formulations
Skin Care Products (e.g., Moisturizers, Serums)
Caproic Acid is widely used in moisturizers and serums for its hydrating and skin-soothing effects. Ideal for dry or sensitive skin formulations, providing a smoother and more comfortable feel
- Concentration: 0.5%–3%
- Benefit: Helps reduce dryness, soothe irritated skin, and improve overall skin texture.
Hair Care Products (e.g., Shampoos, Conditioners)
In shampoos and conditioners, Caproic Acid is used for its conditioning properties and ability to add shine to the hair.
- Concentration: Below 2%
- Benefit: Contributes to a silky texture, improving hair manageability.
Soaps and Body Washes
Caproic Acid acts as a foaming agent and skin conditioner in cleansing products like soaps and body washes.
- Concentration: 1%–3%
- Benefit: Helps maintain a healthy skin barrier while adding a gentle lather.
Compatibility with Other Ingredients
Soluble in organic solvents and compatible with most cosmetic ingredients, making it versatile for various formulations. Sensitive to high heat—requires careful temperature control during formulation. May cause mild irritation in sensitive skin; patch testing is recommended.
Stability and Shelf Life
Caproic Acid is stable under standard storage conditions, but it should be stored carefully to preserve its efficacy. Use sealed bottles or other airtight packaging to minimize exposure to air, which could affect product stability.
- Shelf life: 12–24 months
- Best storage: Keep in airtight containers, away from heat and light to preserve its effectiveness.
Formulation Challenges and Troubleshooting
Caproic Acid presents several formulation challenges due to its potential for irritation and sensitivity to heat:
Heat Sensitivity
Caproic Acid is sensitive to high temperatures, which can affect its stability in formulations.
Solution: Use low-temperature processing techniques to maintain its stability and efficacy.
Skin Irritation Potential
At higher concentrations or in sensitive individuals, Caproic Acid may cause mild irritation.
Solution: Limit use to recommended concentrations and conduct patch testing before introduction to the market.
Odor and pH Balance
Caproic Acid has a distinct odor and may affect the pH of formulations.
Solution: Balance with complementary fragrances and pH adjusters to maintain product stability.
Regulatory Compliance
Ensure compliance with local regulations regarding the use of Caproic Acid in cosmetics.
Solution: Consult regulatory guidelines for specific applications and regions.
Is Caproic Acid Safe in Cosmetics?
Safety reports for Caproic Acid are given below:
- Safety Assessment of Fatty Acids & Fatty Acid Salts as Used in Cosmetics. Download PDF
Regulatory Considerations for Using Caproic Acid in Cosmetic Formulations
Few Regulatory considerations are to be taken into account before using Caproic Acid as an ingredient. Given below is the list of those regulations:
FDA Requirements: Caproic Acid (Hexanoic Acid) is permitted as a food additive for human consumption as a synthetic flavoring substance and adjuvant. It must be used in the minimum quantity required for its intended effect and in accordance with good manufacturing practices.
REACH Registered Substance: Caproic Acid is registered under REACH with active status as of August 12, 2022.
New Zealand EPA Inventory of Chemical Status: Hexanoic Acid (Caproic Acid) does not have individual approval but may be used under an appropriate group standard.
The Australian Inventory of Industrial Chemicals: Listed as hexanoic acid in the Australian Inventory of Industrial Chemicals.
Caproic Acid Side Effects
Caproic Acid is a fatty acid that can cause irritation upon exposure. Inhalation of vapors may lead to respiratory distress, including coughing and throat irritation. Skin contact can result in dermatitis or irritation, while ingestion may cause gastrointestinal discomfort, including nausea, vomiting, and diarrhea.
In laboratory settings, Caproic Acid has been classified as a mild irritant. The substance can also pose risks to aquatic life, indicating potential environmental toxicity. Proper handling and usage precautions are advisable to minimize exposure risks. The LD50 for oral ingestion in rats is reported to be approximately 1,500 mg/kg, suggesting moderate toxicity.
Chronic exposure to Caproic Acid may lead to more severe health effects, although detailed long-term studies are limited. Always ensure that safety data sheets are consulted for handling guidelines and first aid measures in case of exposure.
Potential Risks
Given below is the list of potential side effects associated with the use of Caproic Acid in cosmetics:
- Ulcerative colitis
- Irritable bowel syndrome
- Nonalcoholic fatty liver disease
- Celiac disease
- Autism
- Pervasive developmental disorder
- Crohn’s disease
- Colorectal cancer
- Clostridium difficile infection
- Medium Chain Acyl-CoA Dehydrogenase Deficiency
Symptoms
- Eye Exposure: May cause redness, pain, and blurred vision.
- Skin Exposure: May cause redness and pain.
- Inhalation Exposure: May cause coughing and sore throat.
Interactions
Caproic Acid and octanoate inhibit T3-induced activation of lipogenic enzymes (malic enzyme and fatty acid synthase) in chick embryo liver cells by blocking transcription within 30 minutes. This effect is reversible after 2 hours without fatty acids and does not affect general gene transcription (e.g., GAPDH, β-actin).
The inhibition is not due to reduced T3 receptor binding. Interestingly, carnitine and 2-bromooctanoate enhance T3-induced mRNA accumulation of these enzymes, and hexanoate amplifies carnitine’s effect, suggesting they may share a regulatory pathway. The active inhibitor is likely a metabolite of hexanoate or octanoate.
Toxicity Data
LC₅₀ in mice is 4,100 mg/m³ over a 2-hour exposure, indicating moderate inhalation toxicity.
Adverse Effects
Caproic Acid acts as a dermatotoxin, capable of causing skin burns. It may also induce toxic pneumonitis—lung inflammation caused by inhalation of harmful vapors or fumes.
Exposure Routes
Caproic Acid can be absorbed into the body through inhalation of its aerosol and via skin contact.
Carcinogen Classification
No indication of carcinogenicity to humans (not listed by IARC).
Antidote and Emergency Treatment
In cases of severe exposure, consider orotracheal or nasotracheal intubation, especially if the patient is unconscious, shows signs of severe pulmonary edema, or is in respiratory distress. Early intubation may be necessary with signs of upper airway obstruction.
Use positive-pressure ventilation with a bag-valve mask if beneficial. Treat pulmonary edema with appropriate medications and administer a beta agonist like albuterol for severe bronchospasm. Continuously monitor cardiac rhythm and manage arrhythmias as needed. Initiate IV D5W at a minimal rate, or use 0.9% saline (NS) or lactated Ringer’s (LR) if hypovolemia is present.
Administer fluids cautiously in hypotensive patients and watch for fluid overload. Vasopressors may be required if hypotension persists despite normal fluid volume. For eye exposure, use proparacaine hydrochloride to assist irrigation.
Environmental and Sustainability Impact
Caproic Acid is a medium-chain fatty acid used in cosmetics for its antimicrobial and emollient properties. Its use raises environmental and sustainability considerations:
Environmental Impact
- Water Pollution: Caproic Acid is biodegradable and generally non-toxic to aquatic organisms. However, improper disposal in high concentrations may contribute to localized water contamination.
- Carbon Footprint: The production of Caproic Acid typically involves chemical synthesis or extraction from natural sources like coconut oil, which can be sustainable if managed correctly.
Sustainability
The sustainability of Caproic Acid depends on its sourcing and production methods.
- Raw Materials: Caproic Acid is usually derived from natural sources like coconut oil or palm kernel oil, which can be sustainably sourced if certified organic or responsibly harvested.
- Energy Use: Manufacturing requires moderate energy input. Cleaner energy sources and efficient processes can reduce its environmental impact.
- End-of-Life Impact: Caproic Acid is biodegradable and breaks down naturally in the environment, posing minimal long-term ecological risks.
Biodegradability and Toxicity
Caproic Acid is readily biodegradable and generally non-toxic to humans and the environment under normal use conditions.
Ammonia Toxicity: Not applicable. Caproic Acid does not release ammonia or harmful byproducts during decomposition.
Eco-Friendly Alternatives
For those seeking sustainable alternatives to Caproic Acid, the following options may be considered:
- Caprylic/Capric Triglyceride: A mixture derived from coconut oil, offering similar emollient properties with a potentially lower environmental footprint.
- Olive Oil Fatty Acids: Derived from olive oil, these fatty acids provide moisturizing benefits with a sustainable sourcing potential.
- Linoleic Acid: An omega-6 fatty acid with moisturizing properties and can be sourced from sunflower or safflower oil.
Alternatives of Caproic Acid and Comparative Analysis
Given below is the list of alternative ingredients that can be used in place of Caproic Acid in cosmetic formulations:
- Caprylic Acid
- Capric Triglyceride
- Lauric Acid
- Oleic Acid
- Sodium Lauryl Sulfate (SLS)
Comparative analysis of Caproic Acid alternative ingredients:
| Ingredients | Strengths | Limitations | Efficacy | Cost | Stability | Compatibility | Safety |
| Caprylic Acid | Medium-chain fatty acid with antimicrobial and cleansing properties Acts as a surfactant and emulsifier, improving product texture and stability Provides moisturizing and skin conditioning benefits Widely used and well-studied in cosmetic formulations | Can be irritating at high concentrations Less effective as a fragrance enhancer compared to caproic acid | High as a cleansing, emulsifying, and antimicrobial agent | Moderate | High (stable in typical cosmetic formulations) | Good with oils, surfactants, and emulsifiers | Generally safe but may cause irritation in sensitive skin |
| Capric Triglyceride | Derived from capric acid and glycerin, acts as an emollient and texture enhancer Lightweight, non-greasy feel with good skin absorption Improves product spreadability and stability Non-comedogenic and widely accepted in skincare | Not a primary cleansing or surfactant agent Higher cost compared to simple fatty acids | High as an emollient and skin conditioning agent | Moderate to high | High | Excellent in oil-based and emulsified formulations | Generally safe and well tolerated |
| Lauric Acid | Medium-chain fatty acid with strong antimicrobial and cleansing properties Contributes to foam formation and skin barrier support Widely used in cleansing and conditioning products | Can be more irritating than caproic acid at higher concentrations Less water-soluble, requiring emulsifiers | High as antimicrobial and cleansing agent | Moderate | High | Good with surfactants and emulsifiers | Generally safe but may cause irritation in sensitive skin |
| Oleic Acid | Longer-chain fatty acid with excellent emollient and moisturizing properties Improves skin softness and barrier function Widely used in creams and lotions | Less antimicrobial activity compared to caproic acid Can be comedogenic for some skin types | Moderate as emollient and skin conditioning agent | Low to moderate | Moderate (prone to oxidation if not stabilized) | Good with oils and emulsifiers | Generally safe |
| Sodium Lauryl Sulfate (SLS) | Powerful surfactant and cleansing agent Highly effective at removing oils and dirt Widely used in shampoos, soaps, and cleansers | Can be irritating and drying to skin and hair Not suitable for sensitive skin or mild formulations | Very high cleansing and foaming ability | Low | High | Good with most surfactants and formulation types | Potential irritant, especially in leave-on products |
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