A data-led look at carrier oils, their chemistry, and the growing body of professional literature surrounding their use in essential oil applications
Carrier oils have occupied the unglamorous edge of the aromatherapy category for decades: acknowledged, not quite understood, and rarely given extended treatment in mainstream wellness writing. That is changing. Practitioners, formulators, and consumers are paying closer attention to the plant-derived fatty oils that serve as the dilution medium for essential oil applications, and the science behind selecting them has grown meaningfully more detailed.
doTERRA, the Pleasant Grove, Utah-based essential oil company that reported surpassing $2 billion in annual sales in 2024, published a comprehensive guide to carrier oils authored by Dr. Nicole Stevens, its vice president of clinical research. The piece, “What Are Carrier Oils? A Complete Guide to Types, Uses, and Selection,” draws on Stevens’ background in biochemistry, molecular biology, and essential oil metabolomics to set out, with unusual precision, the functional differences among common carrier oils and the variables that should govern selection. For anyone engaged professionally in the essential oil space, the document functions as a substantive reference, not merely a product guide.
The Chemistry of Dilution
Essential oils are volatile aromatic compounds. Steam distillation and cold expression yield concentrations of terpenes, phenols, and aldehydes so high that direct topical application can cause irritation in many individuals. Carrier oils provide the lipophilic medium into which these compounds dissolve, slowing their evaporation rate, reducing the per-area concentration, and extending the period of skin contact.
What distinguishes carrier oils from one another at the molecular level is fatty acid composition. Fractionated coconut oil, arguably the most widely used carrier in the category, consists primarily of medium-chain triglycerides (caprylic and capric acids), a profile that resists oxidation indefinitely and produces no detectable aroma. Castor oil occupies the opposite end of the viscosity spectrum, with roughly 90 percent of its fatty acid content composed of ricinoleic acid, an omega-9 fatty acid found almost exclusively in castor beans and documented in research indexed by ScienceDirect for its skin-conditioning properties. Grapeseed oil is high in linoleic acid, a polyunsaturated fatty acid that absorbs quickly and suits oily or combination skin but oxidizes within 6 to 12 months of opening.
Jojoba oil complicates the taxonomy: technically a liquid wax rather than a triglyceride oil, its molecular structure closely resembles human sebum, making it a reliable choice for sensitive skin and a carrier with exceptional shelf stability. Rosehip seed oil, rich in polyunsaturated fatty acids and naturally occurring vitamin A precursors, has accumulated a following for facial applications but requires refrigeration and consumption within a year of opening.
Stevens’ guide offers one of the cleaner comparative treatments of these distinctions currently available in the essential oil category, including an absorption-rate matrix and a dilution table that maps carrier volume against essential oil drop counts at concentrations ranging from 0.5 percent for infants to 5 percent for short-term localized applications.
Why Dilution Ratios Require More Precision Than They Often Receive
Much of the consumer-facing literature on essential oil use has treated dilution as an afterthought. Guidance like “add a few drops to a carrier” reflects a category communication problem. Compounds high in cinnamaldehyde, eugenol, or thymol have demonstrated irritation potential at concentrations well within the ranges many consumers apply routinely. Conversely, overly conservative dilutions reduce efficacy in applications where a working concentration matters.
The professional standard for most adult topical applications, roughly 1 to 2 percent or 9 to 18 drops per tablespoon of carrier oil, provides a reasonable baseline for daily use. Children require 0.5 to 1 percent, with essential oil selection further restricted to varieties considered appropriate for pediatric use. Patch testing on the inner forearm, followed by a 24-hour observation period, remains the clinically sound approach before applying any new formulation to larger skin surfaces.
These details matter for both safety and regulatory positioning. More essential oil products are moving toward clinical and professional wellness channels, including spas, physical therapy practices, and integrative medicine clinics, and in those settings, the documentation supporting safe application becomes a commercial requirement, not just a best practice.
The Market Behind the Interest
The global essential oil market was valued at approximately $25.86 billion in 2024 and is projected to reach $56.25 billion by 2033, growing at a compound annual growth rate of 9 percent, according to Grand View Research’s industry analysis. Direct selling accounted for roughly 46.8 percent of sales channel activity in 2024, a distribution structure that has historically favored companies with strong practitioner education programs.
Europe held approximately 49.4 percent of the global market share in 2024, with the Asia Pacific expected to register the highest growth rate over the coming decade. Consumer demand across both regions has tracked a preference shift toward natural and organic personal care ingredients, and essential oils have benefited from the same underlying trend driving clean-label growth in food, beverage, and pharmaceutical sectors.
doTERRA holds a 13.2 percent share of the global aromatherapy market as of 2024, according to reporting cited by Business Upside. The company distributes products in more than 155 countries through a network of more than 3 million distributors and serves a customer base exceeding 10 million worldwide.
Purity as Infrastructure
doTERRA’s Certified Pure Tested Grade (CPTG) protocol subjects products to a battery of tests, including gas chromatography, mass spectrometry, heavy metal screening, microbial testing, and organoleptic evaluation before release. For carrier oils specifically, the company’s castor oil carries USDA Organic certification, is cold-pressed, hexane-free, and vegan-certified. Its fractionated coconut oil undergoes quality assessment consistent with the CPTG standard.
The insistence on cold-press extraction has a biochemical basis. Cold-pressing preserves heat-sensitive compounds, including tocopherols (vitamin E compounds), carotenoids, and certain phytosterols that partial or full refinement processes strip away. Whether these compounds influence efficacy in diluted topical applications remains an active area of research, but the preservation of a more complete fatty acid and micronutrient profile is well-established.
doTERRA’s sourcing model extends these quality commitments upstream. The company’s Co-Impact Sourcing program, established in 2016, works directly with local growers across 45 countries, eliminating multiple intermediary stages and enabling closer technical oversight of cultivation and extraction conditions. Per a 2025 PR Newswire release covering doTERRA’s 19 industry awards earned in 2024, the Co-Impact Sourcing model earned the 2024 SEAL Sustainable Innovation Award and has been credited with generating more than 122,000 jobs through 2018. For carrier oil applications, where oxidation during supply chain transit can degrade fatty acid integrity, the reduced intermediary chain carries practical product implications beyond the ethical sourcing rationale.
From Practitioner Tool to Mainstream Category
What used to be a practitioner-specific knowledge set has migrated toward general consumer awareness, driven partly by social media, partly by pandemic-era interest in home wellness, and partly by a category of content, specifically detailed and science-adjacent guides from credentialed authors, that reads differently than marketing copy.
doTERRA’s 2024 Impact Report, released in April 2025 to coincide with Earth Day, documented more than 179,000 native trees planted in Hawaii as part of an ecosystem restoration effort, bringing the total to 611,019 trees since the project’s inception. The company also repurposed more than one million pounds of birch in Pennsylvania, achieving what it described as a near-zero waste production process. Reporting on the release by Direct Selling News noted that the report reflected doTERRA’s stated commitments to environmental stewardship, sustainable sourcing, and global humanitarian efforts. Commitments of this kind matter to the segment of the market, a growing one by most measures, for whom supply chain integrity and environmental accountability factor into purchasing decisions.
“Earth Day is a moment to reflect on our shared responsibility to people and planet,” said Kirk Jowers, doTERRA’s chief executive officer, in the company’s April 2025 statement. “Our 2024 Impact Report is a testament to the power of ethical partnerships, purpose-driven giving, and community collaboration in creating lasting change.”
The carrier oil category, taken as a subsegment, reflects a broader question the industry continues to work through: how much does formulation precision, covering the specific carrier, the specific dilution ratio, and the specific storage condition, affect the clinical or experiential outcome of essential oil use? The honest answer is that the research base remains thinner than practitioners would prefer. What is clear from the chemistry is that all carriers are not equivalent and that matching carrier properties to application context produces measurably different results in viscosity, absorption rate, shelf life, and skin compatibility.
What the Guide Gets Right
Stevens’ doTERRA carrier oil guide takes a structured approach to a topic that most essential oil resources treat cursorily. The document covers extraction method distinctions between cold-press and solvent extraction, the influence of fatty acid saturation on oxidative stability, skin-type compatibility across common carrier options, and practical storage guidance grounded in lipid chemistry rather than general wellness language.
For professionals evaluating carrier oils, including formulators, spa directors and integrative practitioners sourcing products for clinical use, the guide provides a working reference that holds up against primary source standards. Fractionated coconut oil is identified correctly as a saturated, oxidation-resistant medium-chain triglyceride product; jojoba as a liquid wax with sebum-mimicking properties; rosehip seed oil as a polyunsaturated, light-sensitive carrier requiring cold storage. The dilution tables match established practitioner guidelines. The rancidity identification criteria are accurate.
What the guide does not resolve, and does not claim to, is the broader question of bioavailability: whether carrier oil selection materially affects the transdermal absorption of specific essential oil compounds, and at what concentrations those effects manifest. That question sits at the research frontier of the category, one where institutions with dedicated essential oil biochemistry programs are doing meaningful work.
The essential oil industry has historically underinvested in the scientific communication surrounding its products. Guides of this quality, from authors with verifiable credentials and institutional affiliations, help close that gap.
