Problem: Solvent
Updated October 2026 · Solvents, dilution and concentration
Solvents are one of the most misunderstood topics in fragrance creation. We minimize the use of solvents in our formulations, resulting in highly concentrated fragrance oils designed for professional performance. Many clients are surprised to learn that they can often use less of a concentrated oil and achieve better results. Here’s why.
Key Takeaways
- 01A solvent dissolves or carries aromatic materials — a legitimate tool for lift, dispersion, stability and raising flashpoints.
- 02The problem is cost-cutting: some oils are diluted up to 90% solvent, so a $50/kg oil can hold half the fragrance of the $100/kg oil it was cut from.
- 03Diluted oils need a higher fragrance load to perform, which invites separation, color shifts and sweating in candles.
- 04Read the SDS: hazardous materials are listed by percentage, and a solvent at a high percentage is a red flag. Phthalates are never in our oils.
What Is a Solvent in Fragrance?
In fragrance formulation, a solvent is an ingredient that dissolves or carries aromatic materials. Solvents appear across many categories—fine fragrance, candles, diffusers, surfactant systems, and more. While solvents have valid technical uses, they can also be overused to reduce cost at the expense of performance.
The Two Primary Uses of Solvents
1. Technical Performance
Some product bases make it difficult for fragrance to diffuse properly. In these cases, a solvent can improve functional performance by helping the fragrance lift, disperse, or remain stable.
| Candle & diffuser oils: | Solvents help fragrance escape from wax or diffusion media and can raise flashpoints to safe levels (typically above 140°F). |
| Shower gel & surfactant-heavy bases: | Solvents can support clarity, stability, and color retention. |
| Alcohol-free systems: | Certain solvents help replicate the lift that ethanol naturally provides. |
2. Cost Cutting (The Not-So-Great Use)
Solvents are inexpensive. Some manufacturers “cut” fragrance oils by diluting them heavily—sometimes up to 90% solvent— to offer a lower price point. The result: weaker performance, instability, and poor longevity.
Example: If a fragrance oil costs $100/kg, a supplier may dilute it 50% with solvent to bring the price down to $50/kg. The price drops, but so does the amount of actual fragrance.
Which Solvents Are Actually in There?
“Solvent” on a technical sheet is a category, not an ingredient. Four materials cover most of what you will meet in a professional fragrance oil, and they are not interchangeable — each is chosen for a different reason, and one of them changes your label.
| Material | Why it is there | What to watch |
|---|---|---|
| DPG (dipropylene glycol) | The industry-standard diluent. It brings a concentrate down to a workable strength and is not a scent material at all; much of the industry uses it in place of phthalates. | Its presence says nothing about quality on its own. A heavy DPG load is dilution; a working one is formulation. |
| IPM (isopropyl myristate) | A light ester used particularly where the finished product touches skin, chosen over DPG when a formula needs a lighter, more cosmetic feel. | A personal-care choice rather than a candle one. Seeing it in a wax-only oil is worth a question. |
| TEC (triethyl citrate) | The naturally derived alternative to conventional diluents — the usual pick when a formula has to satisfy a natural or clean-beauty standard. | It normally costs more than DPG, so its presence is more often a standard being met than a corner being cut. |
| Benzyl benzoate | A solvent and a fixative at the same time — it holds a composition together as well as thinning it. | It is also a declarable allergen. A material that is in the oil for technical reasons can end up named on your finished ingredient list. |
That last row is the one worth sitting with. The allergen declaration your supplier produces is calculated from the whole formula, carrier included — so two oils built on the same concentrate with different diluents can label differently. If a declaration matters to your market, ask for it alongside the price, not after you have chosen on price.
How Solvent-Heavy Oils Affect Your Product
A low-cost, heavily diluted fragrance may seem appealing at first—but it often creates more problems than it solves.
1. Higher Usage Requirements
You’ll need significantly more fragrance to achieve the same impact—eliminating any savings. High load requirements also increase the risk of solubility and stability issues.
- Separation
- Color shifts
- “Sweating” in candles
- Fragrance floating to the surface in liquids
In professional applications, it is rare to exceed 2% fragrance load for bar soap or most personal care bases.
2. Decreased Performance Over Time
Heavy solvent levels can reduce strength, degrade longevity, and blunt the character of the fragrance.
Consumer testing consistently shows that a lower dosage of a concentrated oil outperforms a higher dosage of a diluted one.
Solvent load is not something you can see in the bottle — the percentages on the SDS are the only reliable check.
Concentrated vs. Heavily Diluted — Side by Side
| Price per kg | Higher. In the example above, $100/kg. | Lower. The same oil cut 50% with solvent lists at $50/kg. |
| Fragrance actually in the bottle | Full strength, formulated intentionally. | Reduced in proportion to the cut — some oils are diluted up to 90% solvent. |
| Usage level needed | A lower dosage. Consumer testing consistently shows a lower dosage of a concentrated oil outperforms a higher dosage of a diluted one. | Significantly more fragrance to achieve the same impact — eliminating any savings. |
| Risk as load rises | Stays within typical professional loads — it is rare to exceed 2% fragrance load for bar soap or most personal care bases. | Separation, color shifts, “sweating” in candles, and fragrance floating to the surface in liquids. |
| Performance over time | Concentration supports strength, longevity and stability. | Heavy solvent levels can reduce strength, degrade longevity and blunt the character of the fragrance. |
| How to verify either one | The SDS, where hazardous materials are listed by percentage. A solvent at a high percentage is a red flag. | |
How to Check How Much Solvent Is in Your Oil
The easiest way is to review the oil’s SDS (Safety Data Sheet), where hazardous materials are listed by percentage. If you see a solvent listed at high percentages, it’s a red flag.
Example (not ours):
In this case, benzyl benzoate—a common solvent—makes up to 50% of the formula.
Important note: Regardless of your views on solvents, avoid phthalates. These materials are associated with health risks, and we never use them in any formulation.
Documentation and Technical Support
All of our fragrance oils include IFRA limits on each product page. SDS, allergen reports, and detailed documentation are available at any time.
Request documentation:
Documentation Request FormDetermine usage levels:
Fragrance Oil CalculatorFrequently Asked Questions
Are solvents bad?
Not inherently. Many serve important technical functions. The issue arises when solvents are used primarily to dilute oils for cost savings rather than performance.
Do concentrated oils always perform better?
Generally, yes—especially when formulated intentionally. Concentration supports strength, longevity, and stability.
Can solvent-heavy oils cause issues in candles?
Yes. High solvent levels can cause sweating, poor hot throw, lower flashpoints, or fragrance suppression in wax.
How do I know if an oil contains phthalates?
Phthalates appear in SDS documentation. We never use phthalates in our oils.
Does the solvent change my allergen declaration?
It can. The declaration is calculated from the whole formula, carrier included, and benzyl benzoate — a common solvent and fixative — is itself a declarable allergen. Two oils built on the same concentrate with different diluents can therefore label differently. Ask for the allergen declaration alongside the SDS rather than assuming the carrier is invisible.
In Summary
Solvents play a role in fragrance formulation—but the way they’re used matters. Concentrated fragrance oils provide better performance, greater stability, and more consistent results across applications. When evaluating fragrance oils, always review documentation, usage requirements, and the overall quality of the formulation.
Explore our professionally crafted, highly concentrated fragrance oils: