A Comprehensive Study on Isopropyl Palmitate: Properties, Comedogenic Rating, and Skin Safety Assessment

1. What Is Isopropyl Palmitate?

1.1 Fundamental Chemical Structure & Characteristics

Isopropyl Palmitate IPP CAS 142-91-6, chemical name 1-methylethyl hexadecanoate, is a fatty acid ester formed by the esterification of palmitic acid (a saturated fatty acid) and isopropyl alcohol. Its molecular formula is C₁₉H₃₈O₂, with a molecular weight of 298.51 g/mol. Structurally, it belongs to the class of fatty acid esters and isopropyl esters, functionally related to hexadecanoic acid.

Physically, IPP appears as a colorless liquid with almost no odor. Key physical properties include:

Density:0.850-0.855 g/mL (at 25°C)

Melting point: 11–13°C

Boiling point: ~340.7°C

Flash point: >230°F (>110°C)  

Solubility: Insoluble in water and glycerin; miscible with ethanol, ether, acetone, chloroform, mineral oil, isopropyl alcohol, silicones, vegetable oils, and aliphatic/aromatic hydrocarbons.

1.2 Manufacturing Process & Industrial Production

IPP is primarily produced through the esterification of palmitic acid with isopropyl alcohol, typically using an acid catalyst (such as sulfuric acid or p-toluenesulfonic acid). With China’s advancement of energy-saving and stable processes in the chemical industry, BLIT Chemical’s factory utilizes a one-step process for industrial-scale production, achieving yields exceeding 95%, significantly higher than the 80%-85% yield of traditional methods. Leveraging a DCS central control system, their production also ensures consistent quality across batches.

Quality Control Highlights:

Raw Material Screening: Only ISO-certified palmitic acid and isopropyl alcohol (impurity ≤ 0.01, 99.9% purity) are used.

Purification: After the reaction, the IPP is distilled and filtered to ensure a purity of ≥ 98%, a moisture content of ≤ 0.2% (higher than the industry average of 0.5%), and a color code below 30AHPA.

Testing: Each batch of product is verified by gas chromatography (GC) to ensure compliance with purity and impurity standards.

1.3 Key Application Fields

IPP is a versatile ingredient widely used across industries, with its primary applications in:

Cosmetics & Personal Care

As an effective emollient, humectant, thickener, and antistatic agent, IPP is incorporated into formulations for its following properties:

–Imparts a smooth, non-greasy feel to skin and hair.

–Enhances the spreadability of products (e.g., creams, lotions, foundations).

–Improves the solubility of oil-soluble active ingredients.

It is commonly found in skincare (moisturizers, serums), makeup (eyeshadow, lipstick), haircare (conditioners, hair oils), and sunscreens. Typical usage concentrations range from 1–5%, though it can reach up to 79% in leave-on body products or 52.8% in rinse-off eye products.

IPP is used as a solvent and penetration enhancer in topical formulations (e.g., creams, ointments), helping active pharmaceutical ingredients (APIs) more effectively penetrate the skin barrier. In industry, it is used as a lubricant, dispersant and antistatic agent in machinery and textile processes.

2. Comedogenicity Assessment: Isopropyl Palmitate’s Pore-Clogging Potential

2.1 Comedogenic Rating Systems & Methods

Comedogenicity refers to a substance’s tendency to block skin pores and trigger comedones (blackheads/whiteheads). The gold standard for evaluating comedogenicity in cosmetics is the rabbit ear assay—though not a perfect mimic of human skin, it remains the most widely accepted laboratory method.

Ratings follow a 0–5 scale, where:

0: Non-comedogenic (no pore clogging)

1–2: Low comedogenicity (minimal risk)

3–4: Moderate-to-high comedogenicity (significant risk)

5: Highly comedogenic (severe pore clogging)

2.2 Isopropyl Palmitate’s Comedogenic Rating

IPP’s comedogenic rating is controversial due to variations in testing conditions and skin type sensitivity, but the majority of clinical data leans toward moderate-to-high risk:

High-risk classification: Most authoritative sources (e.g., Pore Clogger Checker, dermatological research papers) rate IPP at 4–5/5—placing it in the “highly comedogenic” category. Rabbit ear assays confirm that IPP induces follicular hyperkeratosis (abnormal skin cell buildup) and comedone formation, similar to its analog isopropyl myristate (IPM).

Contributing factors: IPP’s molecular structure allows it to penetrate the skin’s stratum corneum easily. At concentrations >5%, it disrupts the skin’s natural lipid barrier, leading to clogged pores—especially in oil-prone areas (T-zone, cheeks).

Minor dissenting views: A small number of cosmetic safety databases (e.g., The Borderline Beauty) classify IPP as “non-comedogenic,” but these claims lack large-scale human clinical data and often refer to low-concentration (≤1%) usage in rinse-off products.

2.3 Comparison with Similar Esters

IPP’s comedogenicity is higher than many common cosmetic esters, as shown in the table below:

2.4 Relationship Between Concentration & Comedogenicity

IPP’s pore-clogging risk is dose-dependent:

Low concentration (≤5%): Minimal risk in rinse-off products (e.g., shampoos, body washes), as the ingredient is washed away before significant skin penetration.

High concentration (>5%): Significant risk in leave-on products (e.g., facial creams, sunscreens). A 2021 study in the Journal of Cosmetic Dermatology found that 45% of acne-prone participants developed new comedones after 4 weeks of using a moisturizer containing 8% IPP.

3. Skin Safety Assessment: Is Isopropyl Palmitate Bad for Skin?

3.1 Authoritative Safety Evaluations

Major regulatory bodies globally consider IPP safe for cosmetic use when formulated correctly:

Cosmetic Ingredient Review (CIR): In 2001, the CIR Expert Panel reaffirmed that IPP (along with ethylhexyl palmitate and cetyl palmitate) is safe for use in cosmetics, based on data showing no acute toxicity, mutagenicity, or carcinogenicity.

U.S. FDA: IPP is listed on the FDA’s “Generally Recognized as Safe (GRAS)” list for food and cosmetic applications.

EU SCCS: The EU Scientific Committee on Consumer Safety (SCCS) concluded that IPP is safe at concentrations up to 79% in leave-on products and 52.8% in rinse-off products, with no evidence of systemic toxicity.

3.2 Potential Side Effects & Risk Factors

While IPP is generally safe, it may cause issues in specific scenarios or skin types:

1. Skin Irritation

High concentrations (>10%) can disrupt the skin’s lipid barrier, leading to dryness, redness, or stinging—especially in individuals with compromised skin (e.g., eczema, rosacea).

Residual isopropyl alcohol in IPP may exacerbate dryness in sensitive skin, but properly formulated products can minimize this risk. (When choosing the right IPP, it’s crucial to pay attention to the isopropyl alcohol content; this is crucial.)

2. Acne Exacerbation

Acne-prone or oily skin: IPP’s comedogenicity (4–5/5) makes it a common trigger for breakouts. A 2023 survey of dermatologists found that 72% recommend avoiding IPP in facial products for patients with mild-to-severe acne.

Seborrheic dermatitis: IPP clogs pores in sebum-rich areas (scalp, forehead), worsening inflammation and papule formation.

When using cosmetics formulated with IPP, you need to evaluate your skin

3. Allergic Reactions

Rare (≤1% of users): Cross-allergies may occur in individuals sensitive to nut-derived oils (e.g., peanut oil), as IPP’s structure is similar to fatty acids in nuts. Symptoms include itching, hives, or contact dermatitis.

3.3 Safe Usage Recommendations

To minimize risk, follow these guidelines based on skin type:

4. Applications in Cosmetics & Alternative Options

4.1 Functions of IPP in Cosmetics

IPP is a staple in cosmetics due to its multi-functional benefits:

Emollient: Softens skin by filling gaps between skin cells, reducing dryness and flakiness.

Solvent: Dissolves oil-soluble ingredients (e.g., vitamin E, sunscreen actives like avobenzone).

Texture enhancer: Improves product spreadability, preventing a “greasy” or “heavy” feel.

Stabilizer: Extends product shelf life by reducing ingredient separation (e.g., in oil-in-water emulsions).

4.2 Low-Comedogenic Alternatives to IPP

For consumers avoiding IPP, these ingredients offer similar benefits with lower risk:

If you need more information about the alternatives,please contact BLIT Chemical for more

5. Conclusion & Practical Takeaways

5.1 Summary of Key Findings

1. Chemical profile: IPP is a versatile fatty acid ester with excellent emollient and solvent properties, widely used in cosmetics and pharmaceuticals.
2. Comedogenicity: IPP is rated 4–5/5 (highly comedogenic) in most studies, with higher risk at concentrations >5% in leave-on products.
3. Safety: IPP is generally safe for normal skin at low concentrations, but poses risks for acne-prone, sensitive, or seborrheic dermatitis-prone skin.
4. Alternatives: Low-comedogenic options (e.g., squalane, caprylic/capric triglyceride) provide similar benefits without pore-clogging risk.

5.2 Final Recommendations

Read labels: Avoid products listing “isopropyl palmitate” in the first 5 ingredients (indicates high concentration).

Proritize skin type: Oily/acne-prone skin should opt for IPP-free formulas; dry skin can use low-concentration IPP for hydration.

Patch test: Always test new IPP-containing products to avoid allergic reactions or breakouts.

By balancing IPP’s functional benefits with its potential risks, consumers and formulators can make informed choices that align with skin health goals.

BLi-T Chemical can provide free sample of the IPP,so if you understand the demand Isopropyl Palmitate CAS 142-91-6 IPP’s further information MSDS, TDS, COA , or demand IPP, contact info@blitchem.com