We think of essential oils for their therapeutic virtues. But in the world of artisanal soap-making, their sensory dimension is what matters foremost:
“the scent and the ability to transform an ordinary soap into something memorable, even after saponification, which alters some of the aromatic molecules.”
Solid cosmetics (soaps, solid shampoos, balms, conditioners) is a rapidly growing market. According to available sector data, it shows an annual growth rate of around 6 to 8 % in Europe, driven by zero waste trends, clean beauty, and plastic reduction.
It’s a movement we are observing directly: the demand for quality essential oils for saponifiable use continues to grow among artisans and brands that work with us.
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Which essential oils to use for making soap?
The choice must consider three parameters: the olfactory strength, the properties added to the finished product, and the availability of volumes compatible with regular production.
Our priority selection
| Essential oil | Olfactory profile | Key properties | Retention in soap | Indicative price |
|---|---|---|---|---|
| True Lavender (Lavandula angustifolia) | Floral, sweet, classic | Soothing, mild bactericidal | ★★★ | € |
| Lavandin (Lavandula × hybrida) | Floral, slightly camphorous | Purifying, deodorizing | ★★★★ | € |
| Tea Tree (Melaleuca alternifolia) | Fresh, medicinal | Antibacterial, antifungal | ★★★ | €€ |
| Eucalyptus radiata (Eucalyptus radiata) | Fresh, mentholated | Purifying, respiratory | ★★★ | € |
| Geranium Rosat (Pelargonium graveolens) | Floral, rosy, balanced | Rebalancing, astringent | ★★★ | €€ |
| Ylang-ylang (Cananga odorata) | Exotic, sweet, intense | Soothing, nourishing | ★★★★ | €€ |
| Palmarosa (Cymbopogon martinii) | Floral, slightly lemony | Moisturizing, antimicrobial | ★★★ | €€ |
| Peppermint (Mentha × piperita) | Fresh, spicy, lively | Toning, refreshing | ★★ | € |
| Sweet orange (Citrus sinensis) | Citrus, bright | Invigorating, anti-stress | ⭐⭐ | € |
⭐ = weak hold | ⭐⭐⭐⭐ = excellent hold after saponification | € < 30 € / 100 ml | €€ = 30–80 € / 100 ml
Citrus fruits are not listed: hold too weak + photosensitizing risk.
Lavender: an essential reference
Lavender is by far the most used essential oil in soap making.
Its versatility, availability, and universally appreciated scent profile make it a natural starting point for many formulators.
One point deserves clarification:
“No clinical study has demonstrated that these properties are maintained in the finished soap, after saponification and rinsing.”
In soap, lavender primarily acts as a fragrance agent and contributes to the natural image of the product. This is already significant, but it would be inaccurate to make a therapeutic shortcut in this context.
What research shows more broadly: studies conducted at the University of Manchester have highlighted the antimicrobial potential of essential oils, capable of eliminating resistant pathogens (MRSA, Clostridium difficile) in two minutes of contact, opening a pathway for their integration into hygiene products, including soaps, even in hospitals. (Source: Ma Bible des Huiles Essentielles, D. Festy)
The complementary virtues (antioxidant, anti-inflammatory, antifungal) remain minor in this context, and their expression depends on the method of application and concentration. (Source: Université Constantine, 2020)
How to dose essential oils in soap
General dilution rules
For rinse-off cosmetic products (soaps included):
– 1 % essential oils: classic dermo-cosmetic action, everyday product – 3 % essential oils: repair action, more intense effect
Practical reminder: 20 drops ≈ 1 ml. For 1 kg of soap, 1 % represents 10 ml — a quantity that is incorporated by weight, not drop by drop. For non-rinse-off products (creams, balms, solid deodorants), the thresholds are different and stricter.
⚠️ Legal framework — The dosage rules presented here concern artisanal use and homemade products. If you manufacture soaps for sale, European regulation (Regulation 1223/2009) requires an evaluation of safety by a qualified toxicologist or pharmacist*. Dosage and allergen declaration are legal obligations. We provide the technical datasheets and analysis reports necessary for this procedure for each batch ordered.
Essential precautions
Skin tolerance and allergens
All essential oils contain potentially allergenic compounds: IFRA allergens, some of which must be declared when exceeding a certain threshold in cosmetics.
Systematic testing before incorporation: dilution to 2 % in a neutral vegetable oil, applied in the elbow crease, observation for 24 to 48h.
The Cosmos certification
If you are developing a product line positioned as “clean” or “natural”, the Cosmos Organic certification is currently the standard in Europe. It guarantees the naturalness of the ingredients, their origin (certified organic or wild), and the absence of unauthorized synthetics.
Our certified organic French essential oils are available in Cosmos grade upon request.
And hydrosols in soap?
Hydrosols (floral waters) are sometimes considered as an alternative or complement. In practice, their integration into a saponified soap is of little relevance: their concentration of active molecules is very low (0.1–0.5%), and the saponification process alters the compounds they contain.
Sources
– Festy, D. My Bible of Essential Oils. Leduc Editions. – Marchand, J. (2019). Use of Aromatherapy in the Treatment of Stress and Insomnia. Pharmacy thesis, University of Lorraine. https://www.au-bonheur-dessences.com/wp-content/uploads/theses/these-jacques-marchand.pdf – University of Constantine. (2020). Study of the Chemical Composition of Essential Oils from Three Medicinal Plants. https://fac.umc.edu.dz/snv/bibliotheque/biblio/mmf/2020/Etude%20de%20la%20composition%20chimique%20des%20huiles%20essentielles%20de%20trois%20plantes%20m%C3%A9dicinales.pdf – Thesis BC17_0025. Study of Essential Oils in Cosmetic Use. DICAMES. https://dicames.online/jspui/bitstream/20.500.12177/4130/1/FS_These_BC17_0025.pdf
