Castor Oil: Understanding Types, Grades, and Uses

Castor oil is a plant-derived oil extracted from the seeds of the Ricinus communis plant, valued for its unique chemical structure and high ricinoleic acid content. Known for its versatility, castor oil is used in a wide range of industries, including cosmetics, pharmaceuticals, industrial manufacturing, and agriculture, thanks to its lubricating, emulsifying, and moisturizing properties.

However, not all castor oil is created equal. The market offers multiple types of castor oil, each defined by its grade, purity level, processing method, and certifications. Whether you're formulating a skin cream, producing lubricants, or sourcing ingredients for food-grade applications, selecting the right castor oil grade is essential for performance and compliance.
From cold-pressed and refined castor oils to pharmaceutical- or industrial-grade options, understanding the differences helps buyers meet regulatory requirements while ensuring product integrity. Whether your priority is castor oil purity, castor oil percentage of active content, or global certifications like USP or Organic, the right type of castor oil supports safety, efficiency, and results. Let’s explore the most common grades available and what sets them apart.

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In this article, we’ll explain:

1. Common Grades & Purities of Castor Oil

2. Certifications & Standards

3. Chemical Forms & Variants

4. Applications Based on Type

5. How to Choose the Right Type of Castor Oil

Common Grades & Purities of Castor Oil

Food Grade

Food grade castor oil is processed to meet the strict safety standards set by regulatory bodies like the FDA. It is considered safe for human consumption in trace amounts and is commonly used in food coatings, flavorings, and as a mold inhibitor. This high-purity castor oil undergoes rigorous filtration and refining to remove any residual toxins or contaminants. Its clarity and stability make it a trusted ingredient in food and beverage manufacturing.

Pharmaceutical Grade

Pharmaceutical castor oil must meet USP (United States Pharmacopeia) or NF (National Formulary) standards. This ultra-pure form is suitable for use in laxatives, capsules, ophthalmic solutions, and topical medications. Its purity, low acid value, and absence of heavy metals make it safe for both ingestion and topical applications, fulfilling stringent pharmaceutical guidelines.

ACS/Reagent Grade

This reagent-grade castor oil is manufactured for laboratory use, where chemical purity and consistency are paramount. While not intended for medical or food use, it plays a vital role in analytical testing, chemical synthesis, and scientific research requiring minimal variability or contamination.

Industrial/Technical Grade

Industrial grade castor oil is optimized for manufacturing processes rather than human contact. It’s commonly used in the production of adhesives, paints, greases, coatings, lubricants, and biodiesel. While it may not meet pharmaceutical or food-grade purity, it provides excellent oxidative stability and viscosity, making it ideal for demanding mechanical and industrial applications.

Electronic Grade

Less common but highly specialized, electronic-grade castor oil is refined to meet the ultra-low impurity requirements of the electronics and semiconductor industries. It may be used in dielectric fluids, capacitor production, and cleanroom applications where even trace contaminants must be avoided.

Certifications & Standards: Castor Oil

When sourcing castor oil for regulated or consumer-facing applications, certifications are just as important as purity. Let’s take a look:

USP/NF: Meets pharmaceutical requirements for safety and efficacy in drug formulations.
Food-Grade: Certified for use in edible and food-contact applications.
Organic Certified: Produced from non-GMO castor beans grown without synthetic pesticides or fertilizers, in compliance with USDA and EU organic standards.
Kosher & Halal Certified: Suitable for use in products intended for religious dietary markets.
REACH & RoHS Compliant: Ensures the oil is free from hazardous substances, supporting environmental safety and European market access.
Allergen-Free: Free from common allergens, making it safe for personal care, food, and pharmaceutical use.

These certifications ensure your castor oil meets expectations for purity, traceability, and performance across regulated industries and consumer segments.

Chemical Forms & Variants of Castor Oil

While castor oil is most commonly encountered as a viscous, pale yellow liquid, it also exists in modified forms tailored for specific functions. Understanding the physical state and chemical derivatives of castor oil helps users select the right version for industrial, cosmetic, or scientific use.

Liquid Form

The standard type of castor oil used across most industries is the unmodified liquid form. It is hydrophobic, highly viscous, and stable under normal storage conditions. Thanks to its high ricinoleic acid content, it exhibits excellent lubricity, solvency, and emollient characteristics. Liquid castor oil is a go-to option for applications in lubricants, pharmaceuticals, and cosmetics due to its purity and handling ease.

Hydrated vs. Anhydrous Forms

Castor oil is not categorized by water content like many inorganic substances, but moisture exposure can still compromise castor oil purity. Over time, ambient humidity may introduce water into improperly sealed containers, increasing the risk of hydrolysis, microbial growth, or rancidity. For this reason, castor oil should be stored in an anhydrous (dry) environment to preserve chemical stability and shelf life.

Salt Forms & Derivatives

Though pure castor oil does not form traditional salts, several functional castor oil derivatives offer alternative forms and performance profiles:

Hydrogenated Castor Oil: Also known as castor wax, this solid, odorless wax is commonly used in cosmetics, coatings, and plasticizers where a non-greasy finish is desired.
Sulfated Castor Oil (Turkey Red Oil): A water-dispersible version of castor oil used in textiles, hair conditioners, and bath oils. Its sulfate groups allow it to emulsify easily in aqueous systems.
PEG Castor Oils (e.g., PEG-40 Hydrogenated Castor Oil): Polyethylene glycol esters of castor oil, used extensively as emulsifiers in personal care and pharmaceutical formulations.

Each of these variants has different handling requirements and is suited to specific product formulations based on desired consistency, solubility, and function.

Castor Oil Applications Based on Type

Selecting the correct grade and type of castor oil is crucial to achieving reliable, high-performance outcomes in any formulation. Different purity levels, chemical modifications, and certifications enable castor oil to serve across a wide array of industries:

Food & Beverage Applications

Only food-grade castor oil, typically cold-pressed and free of solvents like hexane, is suitable for incidental use in food products. Applications may include mold inhibition, flavor extraction, or as a processing aid under FDA-compliant guidelines. Although not typically ingested in large amounts, it plays a role in safe, clean-label manufacturing.

Industrial Manufacturing

Industrial-grade castor oil is a workhorse in manufacturing. Its high hydroxyl content and chemical reactivity make it ideal for producing biodiesel, polyurethane foams, adhesives, coatings, greases, and plastics. It’s also used in surfactant production and textile treatments. These applications prioritize performance over castor oil purity, making this grade efficient and cost-effective for large-scale use.

Pharmaceuticals & Healthcare

Pharmaceutical-grade castor oil (USP or NF certified) is used both as an active ingredient and excipient in healthcare settings. Common applications include laxatives, oral capsules, topical carriers, and emulsifiers in creams and ointments. Hydrogenated castor oil is especially valued in solid dose formulations for its stability and inert behavior.

Scientific Research & Lab Work

Reagent-grade castor oil is used in laboratory environments where high purity and consistency are essential. It functions as a reagent, carrier, or control compound in studies involving drug delivery, dermatological testing, and chemical synthesis. In research applications, even slight variations in castor oil percentage or composition can affect results, which makes grade selection vital.

How to Choose the Right Type of Castor Oil

Choosing the correct type of castor oil is critical to ensuring safe, effective, and compliant product performance. Castor oil is available in multiple grades, including pharmaceutical, food, cosmetic, and industrial, each tailored to specific end uses and purity requirements.

Purity and Application

The level of castor oil purity needed depends on your formulation goals:

Cold-pressed or virgin castor oil is ideal for personal care and wellness applications due to its minimal processing and solvent-free extraction.
Food-grade castor oil must meet FDA or equivalent safety standards and be suitable for incidental ingestion or food manufacturing.
Industrial-grade castor oil, though more cost-effective, may contain trace impurities and is intended strictly for manufacturing applications such as lubricants, biodiesel, and coatings.

Always verify the castor oil percentage and purity specifications before purchase to ensure compatibility with your product's intended function.

Regulatory Requirements

If your industry is regulated, such as food, pharma, or cosmetics, you must choose castor oil that meets applicable standards:

Look for USP, NF, or BP-certified castor oil for pharmaceutical formulations.
Food production requires FDA-compliant food-grade oil.
Many clean-label or global markets also require supporting documentation like COAs, organic certifications, or Kosher/Halal labels.

Confirm these credentials before use to prevent costly compliance issues.

Industry-Specific Recommendations

Food Industry: Only use food-grade castor oil that complies with FDA or EFSA regulations and is supported by full traceability documentation.
Cosmetic & Personal Care: Opt for cold-pressed, hexane-free oil for safer use on skin and hair.
Pharmaceutical Use: Always select USP-grade castor oil for oral or topical formulations requiring high purity and performance.
Industrial Manufacturing: Technical-grade castor oil may suffice, but ensure its characteristics align with your specific production and material requirements.

Common Mistakes to Avoid

Believing all castor oils are interchangeable.
Using industrial-grade oil in food or skincare products.
Failing to obtain or review certification documents such as COAs.
Overlooking the processing method. Solvent-extracted oils may not be acceptable in clean-label or sensitive applications.

Selecting the right castor oil grade is not just a matter of preference, it’s a critical step in protecting your formulation’s integrity, regulatory standing, and end-user safety. Whether you're working in cosmetics, pharmaceuticals, industrial manufacturing, or food production, always match your oil type to your application needs and certifications.

Looking for high-quality castor oil?

Lab Alley offers a full selection of castor oil grades, including USP, food, and industrial types, available in bulk or smaller quantities. All products come with complete documentation for peace of mind and compliance.

For more detailed guidance, explore our Resource Library for more information.

Our Customer Care team is also available for more information and documentation, including chemical Safety Data Sheets.

Where to Buy Castor Oil

As your trusted partner in chemical supply, Lab Alley is always striving to meet the growing demands of our customers. We want you to be able to access all of your chemical needs in one place, along with streamlined online ordering and fast shipping.

Due to popular demand from our valued clientele, Lab Alley's Castor Oil is available in a range of purities and packaging options to suit various commercial, laboratory, and personal needs.