How to make a natural gel scrub

For Formula Botanica's bi-monthly formulation challenge in Sep-Oct. I've prepared this scrub gel. Scrubs are extremely popular in all variations: water bases, cream, oil scrub, butter scrub, oleogel scrub and so on and making a gel scrub is basically no rocket science but there are a few points that one has to pay attention to before making any scrub:

• Particle size and hardness

Usually you need fine exfoliants for a facial scrub whereas you can use bigger size and harder exfoliants for hand , feet and body. It means you have to know in advance whether you're maing a facial scrub or a body scrub before deciding about the exfoliant and its particle size. Some suppliers offer the same ingredient in different particle size versions, quite fine for facial scrub, medium size for body scrub and a bigger size for strong exfoliation for instance.

• Carrier-exfoliant compatibility

It is quite obvious that your exfoliant should be compatible with the carrier . It means physicochemical, microbial and optical stability just to name a few factors.

You can use salt and sugar in an oil based scrub for example but obviously they wouldn't work in a water containing formulation. Dried herbs are excellent "natural & sustainable" exfoliants but they wouldn't work in a water based product as well because they become wet and smeary (not to speak of the risk of local contamination at the interface between the herb and the solution)

Bleeding is another problem that might happen according to the incompatibility of the carrier and exfoliant. Most coloured seeds and herbs might bleed in one carrier. This is on its own no harmful reaction and would be only an optical phenomenon but would change the appearance of the product. Imagine that your beautiful rose petal powder that looks so pretty when dispersed in a gel starts bleeding in a few weeks and the whole product looks like a smeared mess.

• Viscosity and density

In some scrubs there is no issue when the exfoliant sits at the bottom of the bottle and the consumer blends it with the carrier by shaking the bottle before application (this is often the case with oil scrubs).

In other cases (creams, gels, oleogels) the exfoliant should be uniformly dispersed in the carrier. This means the viscosity and the density of the carrier should be suitable the individual exfoliant. If the exfoliant is too heavy, it would sediment over time. On the other hand if the exfoliant is too light, it would float on top of the carrier. Each of these versions is undesired and this is why you need to adjust the viscosity of the product according to the exfoliant.

• Safety cinsiderations

There are almost no limitations to the choice of exfoliants. Hundred varieties of flower, seed, kernel and even precious stone powders are available to be applied in different exfoliants. The most important factor to be considered, apart from the particle size is the safety of the product. By seeds and kernels for example, one shall consider the possible allergic reactions. Another safety aspect is the application of cosmetic grade ingredients which are carefully tested. Your exfoliant shall be free of hard edges (that would be invisible to the naked eye) that might injure the customer.

Now that we've mentioned some of the important aspects you need to consider before making the scrub let's go to this scrub gel.

Just one more thing:

Consider that with the spreading ban of plastic beads in different part of the world even the mainstream has to come up with some innovative ideas for mass market production of exfoliants and since we all know the mindset of the scientists in the mainstream and the way the scientists and the marekting people think and act, it will take them years to create something even near to all those amazing scrubs you can create in your small labs/kitchens. The market is open to you. Go ahead and create a variety of amazing scrubs for different customers and markets but keep in mind to stability test and challenge test (when necessary) your products.

To the formulation:

Since this is a rinse-off formulation, I kept is quite simple.

BTW, did you know that SIMPLE and even ONE COMPONENT products are very popular at the moment?

I blended Solagum AX and Sclerotium in a blend that would keep the exfoliant dispersed over decades. Sclerotium does not make a gel or create very high viscosities but it is one of the most unique gums in cosmetics because of the smooth texture it creates and because of its capability of keeping suspended ingredients in suspension. It is, in this regard the only "natural" alternative for carbomer polymers.

I've used low concentrations of a mild and natural surfactant. This is both to make the gel a cleansing, foaming and scrub gel and to disperse the essential oil and preservative without any need for a solubilizer. If you make a surfactant-free gel (like this cooling gel), you'll need a solubilizer for the essential oil (and your preservative if it has oil soluble components).

As always before we start I want to recommend you to read our older posts: hygienic manufacturing practice in cosmetic lab and introduction to Basic equipments and utensils for a cosmetic lab.

Ingredients:

Procedure:

1- Disperse the gums in glycerine

2- Blend all ingredients of phase B

3- Disperse the gum phase in phase B, stir until homogeneous. You'll observe the increase in viscosity shortly after gum dispersion

4- Disperse the olive stone powder

5- Blend the surfactant, the essential oil and the preservative. Add this blend to the rest of the ingredients under gentle stirring you don't want to create excessive foam

6- Adjust the pH with lactic acid between 5-5.5

7- Take your micro kit sample and fill the scrub gel in a suitable container (a bottle with a dispersion pump for instance)