Skin brightening soap

Difficulty: Intermediate
Time: 1 hr
Yields: 1200 g soap

Over the years I have been repeatedly asked for a skin whitening soap, but I’ve always been hesitant for going in this direction. The reason for my reluctance is that I believe everyone is beautiful, regardless of their skin colour and ethnicity, and we should stop striving to reach what are sometimes impossible beauty standards. However, after a little research, I realised that there is some benefit to these skin brightening (not actually whitening) products. The purpose of most such products is not to ‘bleach’ or ‘whiten’ the skin, but to chemically exfoliate, dissolving the glue holding the dead skin cells and removing them, which will leave your skin looking fresh and bright.

Admittedly, there are some ingredients that do have an inhibitory effect on melanin production, but these are not without their own risks, including skin irritation and hyper pigmentation. Here’s an interesting study about skin whitening agents:

This recipe I formulated for this shower and bath soap contains papaya and corn silk, two known skin brightening ingredients. Papaya is a popular ingredient in skin whitening products. It doesn’t actually have an inhibiting effect on melanin production. Instead, the enzyme papain contained in papaya works as an excellent chemical exfoliant, dissolving the glue between dead skin cells. Corn silk, on the other hand, can reduce skin pigmentation, as studies have shown: It works by directly interfering with the melanin production. However, in this soap, I am using the corn silk as a mechanical exfoliant, which will help with the removal of the dead skin cells after the papain has loosened them from the skin. Together, they will make your skin look and feel fresh, rejuvenate and boost cell renewal, and help prepare the skin for optimal absorption of your (skin whitening) moisturiser or lotion.

Before starting, please read the safety and precautions post, especially since this tutorial requires the handling of caustic soda!

If you have never made cold-process soap before, I strongly recommend you check out the basic cold process soap tutorial first.

ONE: Prepare your lye as usual and leave to cool down before placing it in the fridge. You will want the lye solution to be fridge temperature (around 4 degrees Celsius). This is important, because the papaya contains sugar and will heat up the soap.

TWO: While the lye solution is cooling down, we can prepare all the other ingredients. First, weigh out the coconut oil and shea butter in a microwaveable jug or bowl, and heat in the microwave until the oils have melted.

THREE: Then, add the olive oil and rice bran oil to the now melted coconut oil and shea butter. Set aside for now.

FOUR: Next, scoop out about 1/2 cup papaya and add the corn silk (fresh or dried) of about 2-3 cobs of corn (a small handful) to a food processor or bullet. Blend until the mixture is as smooth as you can make it.

FIVE: Add the papaya and corn silk puree to the oils and mix it well with a whisk or stick blender.

SIX: Once your lye solution is sufficiently cold (fridge temperature), carefully pour it to the oils/puree mixture and use your stick blender to mix it until it has emulsified.

SEVEN: Add the essential oils or fragrance to the oils/puree mixture and continue mixing with the stick blender until thin to medium trace.

I used a blend of lemon (20 ml) and sandalwood (10 ml) essential oils, which are known for their skin brightening effects.

EIGHT: Pour the soap into your mould and place it in the fridge for several hours to prevent overheating.

NINE: After 2-3 hours, remove the soap from the fridge and leave it on the kitchen bench overnight to set and harden. DO NOT INSULATE THE SOAP!

TEN: The following day, unmould the soap and cut into bars. The bars will need a further 6-8 weeks of curing before they can be used.

Skin Brightening Soap

  • Difficulty: intermediate
  • Print
Before starting, make sure you wear protective goggles and gloves and work in a well-ventilated area, free from any distractions!


  • 400 g olive oil
  • 350 g coconut oil
  • 100 g shea butter
  • 150 g rice bran oil
  • 135 g caustic soda
  • 200 g water
  • 2 teaspoons of sodium lactate
  • 20 ml lemon essential oil
  • 20 ml sandalwood essential oil


  1. Measure out the caustic soda and the water. Then add the caustic soda to the water  (not the other way round!) and stir until the caustic soda has completely dissolved.
  2. Add 2 teaspoons of sodium lactate to the lye solution. This is to help harden the soap.
  3. Place the lye solution in the fridge to cool down to fridge temperature.
  4. Weigh out the coconut oil and shea butter and melt in the microwave or on the stove top until completely melted.
  5. Add the olive oil and rice bran oil to the now liquid coconut oil and shea butter.
  6. Next, blend approximately 1/2 cup of papaya and a small handful of corn silk in a food processor or bullet blender.
  7. Add the papaya and corn silk puree to the oils and give it a good stir with a whisk or a quick pulse with a stick blender.
  8. Add the essential oils. Or use your own fragrance.
  9. Once the lye solution is cold, and making sure you are still wearing protective gear, carefully pour the lye to the oils and, using a stick blender, mix until you reach medium trace.
  10. Pour the soap into your soap mould and place it in the fridge for 2-3 hours.
  11. After 2-3 hours, remove the soap from the fridge and leave to set overnight. DO NOT INSULATE THE SOAP.
  12. The following day, unmould the soap and cut into bars. The bars will need to cure for a further 6-8 weeks until ready for use.


    • Hiya! Unfortunately the arbutin acid (or any acid additives) wouldn’t survive the saponification process (the chemical reaction). You’d be better off adding that to a leave-on product, like a cream or serum. As with all acids, follow manufacturers usage recommendations.

      • If you scroll to the bottom, you’ll find the exact recipe which gives you the amount of caustic soda and water

  1. Why didn’t you freeze the papaya and corn silk juice to dissolve the caustic soda? Any special reason (tips)?

    • Hi Lydia! That would have been another option, but I wanted to add the puree and silk itself instead of just the juice. 🙂

    • Hi Shaila! Yes, cornsilk powder would work just as well, and you can colour the soap if you like!

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