Cheap Essential Oils and Smell Training: What You're Actually Sniffing

The essential oil adulteration problem

Essential oil adulteration is not a fringe concern. It is a recognized industry-wide issue that has been documented by analytical chemists, regulatory bodies, and industry organizations for decades.

The economics are straightforward. Genuine essential oils are agricultural products with variable yields, seasonal availability, and significant production costs. Rose otto requires roughly 10,000 pounds of petals to produce one pound of oil. Even common oils like lavender and eucalyptus have production costs that create a floor price for the genuine product. When a retail bottle is priced significantly below what the raw material costs to produce, something has been changed.

The most common forms of adulteration documented in published industry analyses include:

Carrier oil dilution. A genuine essential oil is mixed with a cheap carrier oil (often fractionated coconut oil or a refined vegetable oil) to increase volume. The bottle still smells like the essential oil, but the concentration of active odorant compounds is reduced. On a GC/MS report, this shows up as an unexpected fatty acid profile or a reduction in the percentage of key compounds.

Synthetic compound addition. The dominant odorant molecule is manufactured synthetically and added to a base. Synthetic linalool is added to low-grade lavender. Synthetic limonene is added to weak lemon oil. Synthetic eugenol is added to clove. The resulting product smells approximately correct to a casual consumer, but the chemical profile does not match the genuine botanical. GC/MS testing reveals this through the presence of marker compounds that do not occur in the natural oil, or through ratios of compounds that are outside the expected range for the species.

Note: The Olfactory Training Kit uses Lavandula x intermedia cv. Grosso (lavandin). Lavandula angustifolia is discussed here for comparison purposes only.

Species substitution. A botanical species is sold under the name of a different one, usually with a different chemical profile. Cassia is sold as cinnamon. Eucalyptus citriodora (lemon eucalyptus, dominated by citronellal) is sold as generic "eucalyptus" in place of cineole-rich species like Eucalyptus globulus or Eucalyptus radiata. Within the lavender category, Lavandula angustifolia (true lavender) and Lavandula x intermedia (lavandin) are both legitimate lavender-category oils, but they have different camphor content and slightly different linalool ratios. They are not interchangeable without a label that identifies which species is in the bottle. For olfactory training, species accuracy matters because the chemical profile dictates what compounds your receptors are being exposed to.

Reconstitution. Individual chemical isolates (often synthetic) are blended together to approximate the scent profile of a genuine essential oil. The result may smell similar to the real thing but lacks the full spectrum of minor compounds present in a naturally distilled oil.

This is not speculative. Analytical studies published in peer-reviewed journals and industry publications have documented these practices across multiple oil types, price points, and distribution channels. The problem is more severe for expensive oils (rose, sandalwood, melissa) but is documented even for common oils like lavender and eucalyptus.

Why this matters specifically for olfactory training

Olfactory training is not aromatherapy. You are not diffusing a pleasant scent into a room for ambiance. You are presenting a concentrated odorant stimulus to damaged or dysfunctional olfactory receptor neurons, twice a day, with the goal of promoting neural activity.

The Damm et al. (2014) multicenter study directly examined whether odor concentration affected olfactory training outcomes. The finding was clear: higher-concentration odors were associated with greater improvement in olfactory test scores than low-concentration odors.

This has a direct implication for oil quality. Every form of adulteration described above (dilution, synthetic addition, species swaps) reduces the concentration of the specific naturally occurring odorant compounds that the training protocol relies on. A bottle of "lavender" oil that is 40% carrier oil delivers 40% less linalool per sniff than a pure bottle. A bottle sold as one lavender species but that is actually a different species delivers a different linalool, linalyl acetate, and camphor profile. Both Lavandula angustifolia and Lavandula x intermedia are legitimate lavender-category oils, but they differ chemically, and an accurate label matters.

You are investing 12 weeks of consistent, twice-daily effort into this practice. The quality of the stimulus you expose your olfactory system to during those 12 weeks is a variable the published research has told us matters.

How to tell what you're getting

There are practical steps you can take regardless of where you buy your oils:

Ask for GC/MS testing data. This is the single most reliable indicator. A company that tests its oils can show you the chemical profile. The specific compounds and their percentages. If a company cannot provide GC/MS data for the oil you are purchasing, that does not automatically mean the oil is adulterated, but it means you have no independent way to verify what is in the bottle.

Check the botanical species. The label or product listing should identify the specific species, for example, Lavandula angustifolia or Lavandula x intermedia cv. Grosso (both legitimate lavender-category oils), Citrus limon, Syzygium aromaticum, Eucalyptus globulus or Eucalyptus radiata. If it just says "lavender oil" or "eucalyptus oil" without a species name, you cannot know which plant it came from. Different species within the same genus can have very different chemical profiles.

Be skeptical of unregulated quality claims. "Therapeutic grade," "clinical grade," "certified pure," and "pharmaceutical grade" are not regulated terms when applied to essential oils sold as consumer products. Any company can use them. They may reflect genuine internal quality standards, or they may be purely marketing language. Without third-party testing data to back them up, they are not verifiable.

Evaluate the price in context. This does not mean expensive is always better, pricing reflects distribution models, marketing budgets, and margin structures as much as oil quality. But if a 15ml bottle of rose otto is priced at $12 and the raw material costs $75-$150 per 15ml at wholesale, that bottle does not contain pure rose otto. The math does not work.

Consider the supplier's transparency. Companies that invest in quality control are generally willing to discuss their sourcing, testing, and supply chain. Companies that deflect these questions or hide behind vague language like "we source from the finest growers" without specifics are providing less accountability.

The four oils in the olfactory training protocol

Each oil in the standard four-scent protocol has its own quality considerations:

Lavender (floral category). Two Lavandula species commonly fill this slot. Lavandula angustifolia (often called "true lavender" or "fine lavender") typically shows linalool 25-45% and linalyl acetate 25-47%, with very little camphor (<1%). Lavandula x intermedia (lavandin. Most often the 'Grosso' cultivar, widely grown in France) typically shows linalool 24-35%, linalyl acetate 28-38%, and camphor 6-10%. Both are legitimate floral-category oils for olfactory training; they have different but complementary profiles, with lavandin having a sharper, more penetrating floral character driven by its camphor content. Common adulteration in either case involves extension with synthetic linalool or dilution with carrier oils. GC/MS testing identifies these. What matters is that the bottle is accurately labeled and chemically verified for whichever species it contains.

Lemon (fruity category). The target species is Citrus limon. Key odorant: limonene (typically 60-75%) and citral. Common adulteration: addition of synthetic limonene (cheap and widely available industrially) and dilution with other citrus byproducts. Lemon oil also oxidizes relatively quickly once opened, shelf life matters for a 12-week protocol. Store tightly capped, away from heat and light.

Clove bud (aromatic/spicy category). The target species is Syzygium aromaticum (clove bud, not clove leaf or clove stem. These have different eugenol ratios). Key odorant: eugenol (typically 75-88%). Clove bud oil is less commonly adulterated than some others due to its relatively low cost, but species substitution (leaf for bud) does occur and changes the chemical profile.

Eucalyptus (resinous category). Two Eucalyptus species commonly fill this slot. Eucalyptus globulus typically shows 1,8-cineole (eucalyptol) at 70-85%. Eucalyptus radiata typically shows 1,8-cineole at 60-75%, with α-terpineol contributing a softer overall profile. Both are valid resinous-category representatives for olfactory training. The species to watch out for is Eucalyptus citriodora (lemon eucalyptus), whose dominant compound is citronellal, not cineole. It belongs in an entirely different scent category. Eucalyptus oils are also sometimes extended with synthetic cineole, which a GC/MS report will flag.

What we do

We source our oils from suppliers who provide GC/MS testing to verify purity and composition for each oil type. We chose to assemble the kit at Advanced Rx (a licensed pharmacy in Fort Washington, PA) because pharmacy environments have built-in standards for ingredient verification, documentation, and traceability that consumer product assembly does not require.

We chose lavender over rose specifically because rose otto is one of the most adulterated oils in the global market, and we were not confident we could consistently source verified pure rose at a price that keeps the kit at $69. We wrote about that decision in detail: Rose vs. Lavender for Olfactory Training: Why We Chose Lavender.

We do not claim that our oils are the only pure oils available. Plenty of reputable essential oil suppliers sell genuine products. What we offer is a verified set (four oils, correct species, correct categories, GC/MS-tested sourcing, assembled in a pharmacy, with a 3-month supply and a free training logbook) so you do not have to evaluate four separate supply chains yourself.

If you are sourcing your own oils and you are confident in their quality, that is a legitimate approach. We wrote about that comparison here: DIY Smell Training vs. a Kit: What You Should Know.

The bottom line

You are about to spend 12 weeks (168 training sessions) sniffing four oils twice a day. That is a meaningful commitment of time and consistency. The quality of the oils you use during those sessions is one of the few variables you can control, and the published research tells us it is a variable that matters.

Whatever you decide (a kit, DIY, or another option) make sure you know what is in the bottle.

Download our free 12-week training logbook (PDF) to track your progress.

The content on this page is for informational and educational purposes only. It is not medical advice and does not replace evaluation or advice from a qualified healthcare provider.