If you dream of fluid body milks, ultra-light emulsions, and fast-absorbing lotions, this post is for you. Today I’ll be teaching you how to make thinner, lighter emulsions—I’m sharing three different strategies that you can mix and match to create the fast-absorbing emulsion of your dreams 😍

This post is part of my ongoing free series on natural lotion formulation, and the sample formulations are all modifications on the base formulation taught in part 1. The previous parts are:

1. Easy Natural Lotion for Beginners
2. How to gently scent lotions with natural ingredients (+2 free formulas!)
3. How to naturally scent lotions with essential oils and natural fragrance oils
4. How to make your lotions thicker
5. How to make your lotion richer

Parts 1, 4, and 5 are pre-requisites for this post. Please make sure you’ve read them first!

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The core strategies

In parts 4 and 5 we learned how to make lotions thicker and richer by using thicker, richer emollients and by increasing the size of the oil phase (the inner phase).

It shouldn’t surprise you to learn that if we’re aiming to do the opposite (make a lighter lotion), we’ll employ opposite tactics 😄

So, our three core strategies are:

• Use lighter, faster-absorbing emollients
• Reduce/remove ingredients that are increasing viscosity
• Decrease the size of the oil phase

You can mix and match these strategies to create the emulsion of your dreams. As with making a lotion thicker and richer, changing the size of the oil phase is the most potent way to change the emulsion.

Whenever you add or subtract something, adjust the amount of water in the formulation to keep it adding up to 100%.

The biggest challenge with thin emulsions

As emulsions get thinner, they become less stable and can split, even if there’s enough emulsifier in the formulation (though different emulsifiers have different strengths & weaknesses, and some do far better with fluid consistencies than others).

Separation can happen quickly (within 24 hours) or take weeks (or even months!) to happen, making formulating thinner emulsions more challenging than formulating thicker ones. Keep an eye on the bottom of your bottles (it’s a good idea to choose a clear bottle so you can supervise the emulsion while you’re developing new formulations); you’ll notice a thin layer of clear water at the bottom with opaque emulsion floating on top of it. Sadness 😢

To prevent sad splitsville, include a small amount of a gum or gelling agent like xanthan gum, guar gum, or hydroxyethylcellulose. Around 0.2% is generally enough, though this will vary with the formulation, emulsifier, and gelling ingredient/gum you’re using. This low concentration isn’t enough to substantially boost viscosity, but it will substantially boost stability! You can also boost viscosity (and stability) with a fatty thickener; I usually choose cetyl alcohol when I want a formulation to be ultra-light and slippy.

I find high shear mixing to be more important with thinner emulsions than thicker ones; while you can often hand-stir a thicker emulsion, a thinner one tends to need to oomph of a high-powered, high-shear mixer to work. I will often blend a thinner emulsion for much longer than I’d blend a thicker one since it’s unable to suspend air bubbles the same way a thicker emulsion can.

Learn more: Ten pieces of equipment for new formulators: Part 2

I’ve got some low viscosity experiments on the go with very low concentrations of emulsifier; the 1:7.5 emulsion split within 12 hours, while the 1:15 emulsion remains stable as it includes 0.2% soft xanthan gum 😄

Learn more: How to make your lotions thicker

How to package low-viscosity emulsions

You won’t want to use a traditional lotion pump for really thin lotions as it’ll spew out far too much product. Jars and tubs also aren’t a great idea as the product can spill very easily.

If you want a pump top, I recommend a treatment pump cap: they’re much better suited to lower viscosity products.

You can also use a bottle fitted with an orifice reducer; this will allow you to shake out the emulsion a drop or two at a time. A bottle with a turret cap can also work well.

If the emulsion is very thin, a bottle fitted with an eyedropper could work.

Spray bottles can work, but it’s difficult to create an emulsion that is both stable and thin enough to mist out of a spray bottle. The smallest amount of viscosity in a formulation tends to mean it comes out of a spray bottle in a jet (kind of like a water gun) rather than a mist, which you might not want.

Whatever you use, I recommend choosing something clear if it’s an untested formulation so you can keep an eye out for splitting.

Strategy 1: Lighter emollients

You can swap the oils & butters in your formulation for lighter, faster absorbing ones. Examples of fast-absorbing oils include camellia seed oil, hazelnut oil, grapeseed oil, and medium chain triglycerides (what we’re already using in this formulation!).

To go even lighter, try esters like isoamyl laurate, Neossance® Hemisqualane, Coco-Caprylate, and isoamyl cocoate. You can also purchase synthetic esters; I love C12-15 Alkyl Benzoate.

This won’t meaningfully change the viscosity of the lotion, but will speed up the absorption speed a bit.

Formulation with a lightweight ester

Light Lotion

Heated water phase
74g | 74% distilled water
5g | 5% sodium lactate (USA / Canada)

Heated oil phase
5g | 5% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% isoamyl cocoate (USA / Canada)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)

For full instructions, please read this post.

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Strategy 2: Reduce/remove ingredients that are increasing viscosity

If the starting formulation includes fatty thickeners or butters, swapping those for a lightweight liquid oil or ester will help reduce the viscosity. Our base formulation doesn’t, but it does use a thickening emulsifier at the higher end of the usage range. Reducing the amount of emulsifier from the higher end to the lower end of the recommended usage range can make a big difference in both viscosity and absorption speed! In this sample formulation I’ve dropped the emulsifier from 5% to 3% and the drop in viscosity is very noticeable. Watch the video to see!

Learn more about emulsifier ranges in this post: How to make your lotion richer

Formulation with less thickening ingredients

Light & Fluid Lotion

Heated water phase
75.8g | 75.8% distilled water
5g | 5% sodium lactate (USA / Canada)

Heated oil phase
3g | 3% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% isoamyl cocoate (USA / Canada)
0.2g | 0.2% xanthan gum (soft) (USA / Canada)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)

For full instructions, please read this post.

Strategy 3: Decrease the size of the oil phase

This is the most potent strategy, and will dramatically reduce the richness and viscosity of your emulsions. In the below formulation I’ve kept the lower emulsifier usage and the lightweight emollient, but reduced both the emollient and the emulsifier by 1/3. The finished emulsion is really light and fluid.

Formulation with a smaller oil phase

Light & Fluid Body Milk

Heated water phase
81.7g | 81.7% distilled water
5g | 5% sodium lactate (USA / Canada)

Heated oil phase
2g | 2% Ritamulse SCG (USA / Canada / UK / AU)
10g | 10% isoamyl cocoate (USA / Canada)
0.3g | 0.3% xanthan gum (soft) (USA / Canada)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)

For full instructions, please read this post.

Other questions

What can I use instead of ______?

Please read this post for more information about substitutions for the base formulation: Easy Natural Lotion for Beginners.

The ingredients mentioned in this post—fatty thickeners, lightweight oils, esters, gums, and other gelling thickeners—are all broad categories of ingredients. You don’t have to use the specific ones I’ve used! The whole point is to try, experiment, and experience for yourself what happens and what you like ❤️

How can I make a low viscosity emulsion that isn’t really lightweight/fast absorbing (aka a thin but rich emulsion)?

You’ll need to use an emulsifier that doesn’t thicken our emulsions, like Glyceryl Stearate (and) PEG-100 Stearate or Montano 202. With these emulsifiers you can create thin emulsions with large oil phases because the larger quantity of emulsifier doesn’t automatically thicken the formulation.

Formulations that do this:

• Phryne’s Milk of Roses (22% emollients + 3% emulsifier)
• Raspberry Lavender Soothing Body Milk (15% emollients + 2% emulsifier)

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