If you’re dipping your toes into clean skincare, chances are you’ve come across lye. If you have, you’ve probably heard the warnings:
It’s too harsh!
It’s dangerous!
It doesn’t belong in skincare!
Yes, lye has earned a bit of a reputation, but, I believe a lot of that reputation is just clever marketing. Create an enemy, then you sell you a product that doesn’t have it. Get what I mean?
Without lye, quality soaps wouldn’t be what they are, and neither would your skincare.
That rich, skin-nourishing lather? The silky, moisturizing cleanse? It all starts with lye.
So, is there any truth to the rumors? Let’s break it all down
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What lye is
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How it’s made
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And its superpower effects on the skin
We’ll also clear up common misconceptions, share best practices for using and storing it, and help you choose the best skincare products that use lye correctly.
Up Close and Personal: What is Lye?
Lye is a highly alkaline compound that has been used for centuries in regular and dedicated soap making, cleaning, and even food preparation. Traditionally, lye was made by soaking wood ashes in water, producing a crude form of potassium hydroxide, also known as potash lye.
Today, sodium hydroxide is the most common form of lye used in soap making, produced through saltwater electrolysis. This process separates sodium, chlorine, and hydrogen ions, resulting in pure sodium hydroxide turned into pellets, flakes, or a liquid solution.
Why is Lye Used in Soap?
Lye plays an essential role in soap making—it’s what transforms fats and oils into actual soap. This process, called saponification, is the foundation of traditional soap crafting. Without lye, you’re not making soap; you’re just mixing oils.
During saponification, lye reacts with fatty acids, breaking them down and forming new compounds: soap and glycerin. This reaction is permanent—once complete, no active lye remains in the finished product. Just like baking a cake, where flour and eggs become something new, lye and oils become a gentle cleansing bar.
Types of Lye: Sodium Hydroxide vs. Potassium Hydroxide
Not all lye is the same. While both sodium hydroxide (NaOH) and potassium hydroxide (KOH) are classified as lye, they serve different purposes in soap making.
1. Sodium Hydroxide (NaOH)
This is the most commonly used type of lye in traditional soap making. When mixed with fats or oils, it produces solid, natural bar soaps that hold their shape, lather well, and last longer. The hardness of the soap depends on the ratios of oils and butters used in the formula, but NaOH is always the foundation for creating a firm bar.
2. Potassium Hydroxide (KOH)
Potassium or Kalium Hydroxide is used to make liquid soaps instead of solid bars. It works similarly to NaOH, but the final product remains soft and fluid rather than forming a solid bar. This is why castile soap, liquid hand soap, and even some shampoos rely on potassium hydroxide rather than sodium hydroxide.
Is Sodium Hydroxide safer than Potassium Hydroxide?
When handled in their raw form, both types of lye can be caustic and require caution. However, once fully saponified, neither NaOH nor KOH remains in the finished soap, making it fully safe for skin, be it as a bar or liquid soap.
Can Soap Be Made Without Lye?
No.
All real soap requires lye at some stage. So-called “lye-free” soaps on the market are often detergent-based cleansers, not true soap. These products may contain synthetic surfactants that strip natural oils from the skin, unlike handmade lye-based soaps that retain glycerin, a natural moisturizer.
Lye Soap and Skin Health—Is It Safe for the Skin?
Yes. One of the biggest myths surrounding lye is that it makes soap too harsh or even toxic for the skin. This misconception stems from confusion between raw lye and properly cured soap.
Unlike its caustic nature in raw form, in finished soaps, lye is completely neutralized during saponification. Once fully cured, there is no active lye left in the soap, making it safe and effective for cleansing.
Moreover, lye soap is naturally alkaline, with a pH between 8 and 10. While slightly higher than our skin’s natural pH, that doesn’t make it harmful. In fact, many gentle cleansers and even water have similar pH levels.
Can Lye Soap Help Acne-Prone Skin?
Yes! Handmade lye soap offers a deep yet gentle cleanse, removing excess oil and bacteria without over-drying. Many acne-prone individuals find that natural, fragrance-free lye soap helps reduce breakouts and inflammation. Look for skin-soothing ingredients like goat milk and
Is Lye Soap Bad for Sensitive Skin?
Not at all. This common misunderstanding has a lot to do with superfatting—the process where extra oils remain in the soap to moisturize and protect the skin. A well-balanced lye soap gently cleanses without stripping natural oils. For sensitive skin, choose bars with olive oil, coconut oil, or shea butter and avoid fragrances or synthetic additives that may trigger irritation.
How to Choose the Right Lye Soap
Choosing the right lye soap formulation can make all the difference in how well you treat your skin. For a top-quality product, consider that a well-made lye soap should always:
✔️ Contain natural oils and butters for hydration, like coconut oil, olive oil, and avocado oil.
✔️ Be free of synthetic detergents (like sulfates)
✔️ Include moisturizing agents like goat milk, aloe, or honey
✔️ Use essential oils or natural scents instead of artificial fragrances
Ingredients to Avoid
Many store-bought “soaps” claim to be clean, yet are actually detergent bars, containing ingredients that can dry or irritate the skin. Watch out for:
🚫 Sodium lauryl sulfate (SLS) – A harsh detergent that strips natural oils
🚫 Parabens – Linked to skin irritation and potential hormone disruption
🚫 Artificial fragrances and dyes – Common triggers for skin sensitivity
Are Essential Oils Safe in Lye Soap?
Yes, but only when done with caution. Pure essential oils are often used to add natural fragrance and skincare benefits to handmade soaps. However, some essential oils can be irritating to sensitive skin, especially in high concentrations.
If you have easily irritated skin, look for soaps with gentle
Lye Safety Concerns, Storage, and Longevity
When properly made and stored, lye soap is completely safe for everyday use. Here’s how to store it accordingly:
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Use a draining soap dish: Use a well-draining dish to keep the soap dry and long-lasting.
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Keep soap bars in a cool, dry place: Choose a breathable container, like a paper bag, to prevent excess moisture buildup.
With proper storage, unopened bars can last 1-2 years whereas used bars can last several weeks to months. Consider that soaps with high superfat content (extra oils left in the bar) may have a shorter shelf life but are more moisturizing.
Legend’s Creek Farm: No Doubts, Just Premium Soaps
Looking for a soap with lye that’s as pure as it is effective? Look no further than Legend's Creek Farm! With over a decade of experience in crafting natural skincare products, our team of dedicated experts ensures every bar is made with care and precision.
Our handcrafted goat milk soaps are formulated with natural ingredients to deeply hydrate and cleanse without compromise. Each of our premium bars is:
✔️ Made with premium oils to deliver essential nutrients to your skin
✔️ Cold-process cured to maintain purity and effectiveness
✔️ Completely free from harsh detergents, sulfates, and synthetic additives
✔️ Packed with natural glycerin for lasting moisture and softness
We take pride in creating clean, cruelty-free skincare using only the best responsibly sourced ingredients. Our commitment to ethical farming ensures our products are not only good for your skin but also the world around us. 👉 Explore our collection today to find your perfect bar!
