Formulate a blue facial cleansing bar for Blue Monday

This is where I purchased my key ingredients:

SCI powder - INCI: Sodium Cocoyl Isethionate

Tegosoft PC31 - INCI: Polyglyceryl-3 Caprate

Check your usual suppliers for the remaining ingredients. Cetearyl alcohol, apricot oil, jojoba oil, shea butter, glycerin, and tocopherol are all widely available from cosmetic ingredient suppliers. Serbian blue clay and blue yarrow essential oil may require a more specialist supplier.

A solid cleansing bar might seem like a simple project, but there's a fair bit going on under the surface. Here's what you're actually practising:

Working with SCI powder in a melt-and-press method - SCI is one of the most widely used surfactants in solid bars, and learning how it behaves when heated and combined with fatty alcohols is a skill that transfers directly to shampoo bars, body bars, and other syndet solids. Getting comfortable with the temperature and consistency at each stage is something that only comes from actual formulating.

Incorporating clays into a solid base - Adding clay to a surfactant bar is straightforward, but understanding how much to use and how it affects the finished product's feel is useful knowledge. Too much clay can make a bar feel drying, so the 2% here is a good starting point for facial use.

Building a simple essential oil blend - This formula uses four oils at low percentages. Learning how to balance top, middle, and base notes in a rinse-off product is a different exercise from blending for a leave-on, because the scent needs to come through quickly during a short contact time.

Understanding emollient balance in a facial cleanser - This bar has a high oil and butter content relative to the surfactant level. That's deliberate, because a facial cleanser needs to feel gentle and conditioning, and the emollients work alongside the refatting agent to counterbalance the surfactant's cleansing action.

Checking the pH of a solid product - As with any solid cleanser, you'll want to check the pH using a 10% solution (1g of bar dissolved in 9g of distilled water). Practising this method in a simple formula builds the habit for more complex systems later.

The oil blend is the most obvious place to start experimenting:

Apricot oil or jojoba oil → sweet almond oil, avocado oil, or hemp seed oil - All are skin-friendly emollients that work well in solid bars. Hemp seed oil is lighter and absorbs quickly, whilst avocado oil is richer and suits drier skin. Keep the total oil percentage the same.

Shea butter → mango butter or cocoa butter - Mango butter has a drier feel than shea, while cocoa butter is firmer and gives the bar more rigidity, so it's a good option if you find the base formula a bit soft.

TEGOSOFT® PC 31 → Lamesoft PO65 - Lamesoft PO65 (INCI: Coco-Glucoside and Glyceryl Oleate) is a widely available plant-derived refatting agent that works well in solid bars. It's generally easier to source than Tegosoft PC31 and gives a similar conditioning afterfeel.

Serbian blue clay → French green clay, kaolin, or pink clay - Each clay has a slightly different colour and absorbency. Kaolin is the mildest and works well for sensitive skin. French green clay is more absorbent and better suited to oilier skin types. Pink clay sits somewhere in between and gives a softer colour.

Essential oil blend — This is a personal preference. Swap in any combination you enjoy, as long as you check the IFRA guidelines for safe usage levels in rinse-off products and keep the total essential oil percentage around 0.60%. If you're not sure which oils work well together or how to build a blend for a rinse-off product, Fiona, our AI Lab Assistant, can help you work that out.

And if you've got a formulation question that needs a quick answer or a second opinion while you're working through any of these swaps, the Smart Formulator Hub is there for exactly that.

Safety Note

This formula is designed for personal use as a rinse-off facial cleanser. It's best suited for normal, combination, or oily skin types. If you have very dry or sensitive skin, you may want to reduce the clay content or patch test carefully before using it regularly.

If you're using essential oils, check the IFRA guidelines for maximum safe usage levels in rinse-off products and be aware of any known sensitisers in your chosen oils. Blue yarrow contains chamazulene, which is generally well tolerated, but always verify with your specific supplier's documentation.

Always perform a patch test before using a new formulation on your face. Apply a small amount of lather to the inside of your wrist, leave for 24 hours, and check for any irritation.

When sourcing your ingredients, make sure you're purchasing from reputable suppliers who provide proper documentation, including Certificates of Analysis (COAs) and Safety Data Sheets (SDS). If you're using any fragrance materials, request the IFRA certificate.

This blog post is for educational purposes only and is not intended to replace cosmetic safety assessments required for commercial sales. If you plan to sell products, a formal safety assessment by a qualified assessor is a legal requirement in the UK and EU.