You may have heard of spirulina as a superfood and supplement, but did you know you can enjoy its natural benefits in soap too?
In this recipe, we are using the spirulina powder to make a dark green soap bar. We are pairing this with lime, spearmint, lavender and grapefruit essential oils for a fresh, uplifting aroma.
Read on to learn how to make your own spirulina soap!
Why Use Spirulina Powder in Soap Making?
If you want a natural way to colour your soap a beautiful rich green colour, then spirulina powder is perfect for you!
Not only that, spirulina powder adds its natural antioxidant and anti-inflammatory properties to the soap which will help reduce inflammation, leaving the skin looking radiant and rejuvenated!
Spirulina Soap Recipe
Equipment:
To make our spirulina soap recipe, you will need:
- Gloves
- Goggles
- Digital scales
- Digital thermometer
- Stick blender
- Soap mould or DIY alternative
- Silicone spatula
- Heatproof bowl
- Plastic measuring jugs, ideally 2x 1L and 1x 2L
Ingredients:

1. Mix the sodium hydroxide solution
- Put your gloves and goggles on, and open the window
- Weigh the water
- Weigh the sodium hydroxide in a separate jug
- Add the sodium hydroxide to the water
- Stir until dissolved
- Leave it somewhere safe to cool, it will be hot!

2. Weigh and heat the oils
- Weigh the cocoa butter, babassu oil and olive oil into a heatproof bowl.
- Melt over a pan of boiling water, or using short bursts in the microwave.
- Once melted, leave to cool.

3. Weigh the essential oils and spirulina powder
- Weigh the lime oil, spearmint oil, lavender oil, grapefruit oil and spirulina powder into a separate bowl.
- Mix well until combined.

4. Test the temperatures
- Test the temperature of the sodium hydroxide solution. It should be between 25C and 40C
- Leave it to cool if necessary, but don't reheat it if it's too cool.
- Test the temperature of the oil mixture. It should be between 35C and 40C
- Leave it to cool or reheat if necessary

5. Blend until trace
- Add the sodium hydroxide solution to your oil mixture
- Using a stick blender, stir and blend in short pulses
- Keep checking how the soap batter thickens
- Test for trace by dripping soap batter across the jug of mixture, if it sits on top for a moment the soap has reached trace.
- Stop blending once the soap has reached trace
- Add your essential oils and spirulina powder mixture
- Blend in short bursts until combined

6. Pour into moulds
- Pour the soap mixture into moulds
- Tap the mould to get rid of air bubbles
- Insulate the soap with a towel
-
Leave on a flat surface for 48 hours before unmoulding

7. Cut and cure
- Unmould the soap and cut into equal sized bars
- Spread out with an air gap between the bars
- Leave the spirulina soap to cure for 4 - 6 weeks and then it is ready to use!
TIP: If you want the beautiful green colour to last as long as possible, we recommend storing the soap in a cool, dark place. If stored in a light room, the green colour will slowly fade. It still looks lovely, but it's not the green colour you started with.
Continue Reading
Now you know how to make a spirulina soap recipe, why not try more recipes?
- Interested in using more natural colourants in your soaps? Make your own orange soap using natural paprika powder!
- Ever made soap with milk? Learn how to make goat's milk soap with this recipe!
- Want to use natural colourants in melt and pour soaps? Try this turmeric soap recipe!
Let us know how you got on with this spirulina soap recipe! Tag us on Instagram or Facebook or use our hashtag #thesoaperyuk