A bar of soap is only as good as the oils it is built from, so the best carrier oils, also known as fixed oils, for soap are the ones matched to the bar you want and the skin that will use it. In soapmaking, carrier oils are the base oils that combine with lye and turn into soap through saponification, distinct from the essential oils used for scent. This guide covers how fatty acids drive a bar's behavior, three oils worth knowing, how to match oils to skin type, and how a formulation team balances them in practice. Botanie Soap has built thousands of natural soap formulas on exactly these decisions.
Also read
- Cold Process Soap: What It Is and How It Is Made
- What Makes a Good Bar Soap? What About Glycerin?
- Natural Soap Benefits
How Carrier Oils Shape a Bar of Soap
Every oil has a fatty-acid profile, and those fatty acids translate directly into how a finished bar behaves. A good bar balances three things at once: hardness, lather, and conditioning.
Lauric and myristic acids, found in coconut and babassu, make a hard, cleansing, bubbly bar, though too much can feel drying. Oleic acid, found in olive, avocado, and sweet almond, makes a conditioning, gentle bar that is softer and slower to lather. Stearic and palmitic acids, found in shea and cocoa butter, add hardness and a creamy, stable lather. The art is balance: a great bar blends cleansing oils with conditioning oils so it lathers well without stripping the skin. That balancing act is the difference between a bar that is merely good and one that is great.
Three Carrier Oils Worth Knowing
Avocado oil
Avocado oil is high in oleic acid and rich in vitamins A, D, and E plus plant sterols, which makes it conditioning and gentle. It suits dry, sensitive, or mature skin and produces a softer bar, so it is typically used at about 20% or less of the oil blend.
Sweet almond oil
Sweet almond oil is high in oleic acid, light, and conditioning. It is a versatile, gentle oil for sensitive skin and is largely interchangeable with avocado or rice bran oil when the rest of the recipe is balanced around it.
Babassu oil
Babassu oil is high in lauric and myristic acids, much like coconut, so it firms and cleanses a bar. A fatty-acid analysis published in The Scientific World Journal found babassu oil is more than half lauric acid, with myristic acid the next most abundant. It feels lighter than coconut and absorbs quickly, which makes it a strong coconut alternative for people who find coconut drying, often used at up to about 30%.
Matching Oils to Skin Type
The right blend, not a single "best" oil, is what makes a bar work for a given skin type.
For dry or mature skin, lean on conditioning oils such as avocado, sweet almond, and olive, add butters like shea, and keep harsh cleansing oils modest. For oily or acne-prone skin, a bit more cleansing oil such as coconut or babassu helps, as long as the bar stays balanced enough not to strip. For sensitive skin, favor gentle, low-fragrance formulas built on oleic-rich oils with minimal coconut. Natural bars formulated this way are part of why natural soap feels different from a mass-market detergent bar.
How Botanie Balances Oils for Your Brand
Choosing oils is one decision; balancing them across a repeatable production run is another, and it is the part most brands underestimate. Botanie builds its bars on a proprietary blend of certified organic base oils: a high-oleic sunflower, whose fatty-acid profile is very close to olive oil, for conditioning; sustainably sourced palm for a hard, long-lasting bar with creamy lather; and coconut for cleansing and bubbles. You can see how that plays out in a real recipe in Botanie's soapmaking process walkthrough.
From that base, the formulation team adjusts oils, butters, and additives to a brand's skin-type goals, scents only with essential oils, colors with herbs and clays, and preserves with plant extracts, never synthetic fragrance. Because the bars are cold process, they keep all of their natural glycerin, and every ingredient is EWG-green-rated. With 25 cut sizes and decades of formulas behind it, Botanie can take a hero oil you have in mind and build a balanced, skin-appropriate bar around it.
Best Carrier Oils for Soap FAQ
What is the best oil for soap making?
There is no single best oil. Hard, cleansing oils such as coconut and babassu are balanced with conditioning oils such as olive, avocado, and sweet almond to suit the skin type you are formulating for.
What oils does Botanie use in its bar soap?
Botanie builds on a certified organic base of high-oleic sunflower for conditioning, sustainably sourced palm for hardness and creamy lather, and coconut for cleansing, then customizes from there with butters, herbs, and essential oils.
Let experts balance the oils for you. Choosing and balancing oils for a specific skin type is exactly what a formulation team does every day. Botanie can craft a natural soap formula around your brand and your customers. Talk to our formulation team.