If you’ve been looking for an ultra-light, low-viscosity, super-hydrating summer moisturizer, I think this satiny Summer Solstice Body Milk might just be it. It smells softly of sunshine on a meadow in July; drizzle it over dry skin and massage it in for feather-light hot-day hydration. You’ll need just nine ingredients, and you can easily customize the formulation with different hydrosols and oils to create something that’s perfect for you. Let’s get started!

This formulation grew out of a series of get-to-know experiments I did late last summer with Glyceryl Stearate (and) PEG-100 Stearate. Since Glyceryl Stearate (and) PEG-100 Stearate doesn’t thicken our emulsions like many common emulsifying waxes I got very excited about making all kinds of super thin emulsions. I whipped up all kinds of ultra-light, ultra-fluid formulations and sprayed them all over my studio in the process 😂 Glyceryl Stearate (and) PEG-100 Stearate definitely lets you create such things, but they won’t necessarily be stable. Boo. As I watched my little condiment cups of assorted emulsions age, I found a small amount of some sort of gelling ingredient was required to create something that wouldn’t split as time passed.

So! For stability, this formulation uses Glyceryl Stearate (and) PEG-100 Stearate as our primary emulsifier and Polyacrylate crosspolymer-6 (Sepimax ZEN) for a stabilizing viscosity bump. The finished product is very definitely still liquid, with a viscosity similar to that of unwhipped 35% milkfat cream. While I think you could put it in a spray bottle if you wanted to, it’s a bit too thick to mist—it’ll come out in a jet instead. For that reason, I opted for a bottle with a treatment pump top, but I think you could use any sort of bottle with a relatively small orifice.

With a summer solstice theme, I knew I wanted this body milk to be ultra-light, so our primary emollient is ultra-light coco caprylate. Made from coconut oil, this ester is sometimes used as a natural cyclomethicone alternative (the trade name on my bottle is ‘Coco Silicone’). Neossance® Hemisqualane would be a great alternative, too! I’ve also added a wee bit of cyclomethicone in the cool down phase for added awesome slip and to further reduce any potential tackiness, but I do think you could just use more coco caprylate if you wanted to—this formulation is pretty slippy and low-tack without the cyclomethicone.

Our water phase is fairly simple with a focus on hydration; hyaluronic acid and propanediol 1,3 offer great humectant benefits without being sticky on the skin. Sweetgrass hydrosol softly scents the entire formulation with a beautiful sunshine-on-warm-prairie-grass scent that makes my prairie girl heart swoon. You could easily use any hydrosol you like instead—I think peppermint would be wonderfully refreshing for summer!

Want to watch this project instead of reading it?

Watch Now

Relevant links & further reading

• Hyaluronic Acid in the Humblebee & Me Encyclopedia
• Propanediol 1,3 in the Humblebee & Me Encyclopedia
• Glyceryl Stearate (and) PEG-100 Stearate in the Humblebee & Me Encyclopedia
• Polyacrylate crosspolymer-6 (Sepimax ZEN) in the Humblebee & Me Encyclopedia
• Liquid Germall Plus in the Humblebee & Me Encyclopedia
• Cyclomethicone + other cyclo-siloxanes in the Humblebee & Me Encyclopedia
• What’s up with hydrosols, distillates, and floral waters?
• Super Simple Moisturizing Lotion with Glyceryl Stearate (and) PEG-100 Stearate

Summer Solstice Body Milk

Heated water phase
32.7g | 32.7% distilled water
20g | 20% low molecular weight 1% hyaluronic acid solution (USA / Canada / New Zealand)
30g | 30% sweetgrass hydrosol
5g | 5% Propanediol 1,3 (USA / Canada)

Heated oil phase
1.5g | 1.5% Glyceryl Stearate (and) PEG-100 Stearate (USA / Canada / UK & EU / Australia)
8g | 8% coco-caprylate (USA / Canada / UK / EU / NZ)
0.3g | 0.3% Polyacrylate crosspolymer-6 (USA / Canada / UK / Australia)

Cool down phase
0.5g | 0.5% Liquid Germall Plus™ (USA / Canada)
2g | 2% cyclomethicone (USA / Canada)

Prepare a water bath by bringing about 3cm/1″ of water to a bare simmer over low to medium-low heat in a wide, flat-bottomed sauté pan.

Weigh the heated water phase into a small heat-resistant glass measuring cup or glass beaker. Weigh the entire lot (measuring cup + ingredients) and note that weight for use later. Weigh the heated oil phase into a second heat-resistant glass measuring cup. Place both measuring cups in your prepared water bath to melt everything through.

After about 20–30 minutes the oil part should be completely melted and the water part should be thoroughly dissolved. Remove the water bath from the heat and weigh the water phase. Add enough hot distilled water to the heated water phase to bring the weight back up to what it was before heating, and then pour the water part into the oil part. Stir with a flexible silicone spatula to incorporate.

Grab your immersion blender and begin blending the lotion, starting with short bursts so the still-very-liquid lotion doesn’t whirl up and spray everywhere. Blend for about a minute, leave to cool for ten, blend for another minute or two, and repeat this blend-cool-blend cycle until the outside of the glass measuring cup is barely warm to the touch and the lotion is thick and creamy.

When the lotion is cool it’s time to incorporate our cool down ingredients. Because cool down ingredients are typically present at very low amounts you’ll need to use an accurate scale—preferably one accurate to 0.01g. As these more accurate scales tend to have fairly low (100–200g) maximum weights you won’t be able to put the entire batch of lotion on that scale without blowing it out. So—grab a smaller dish. Add a scoop or two of lotion, and then weigh the cool down ingredients into that, using the more accurate scale. Stir to thoroughly incorporate, and then stir all of that back into the master batch of lotion. Doing it this way minimizes the amount of cool down ingredients lost to the secondary container.

Once the cool down phase has been incorporated, all that’s left to do is package it up! This formulation is thin enough that you’ll be able to pour it straight into the bottle if you’ve got a relatively steady hand. I used a 100mL (3.3fl oz) airless pump bottle from YellowBee. Whatever you use I recommend choosing something with a fairly small dispensing hole as this is a very fluid emulsion.

Use as you’d use any lotion or cream. Enjoy!

Shelf Life & Storage

Because this cream contains water, you must include a broad-spectrum preservative to ward off microbial growth. This is non-optional. Even with a preservative, this project may eventually spoil as our kitchens are not sterile laboratories, so in the event you notice any change in colour, scent, or texture, chuck it out and make a fresh batch.

Substitutions

As always, be aware that making substitutions will change the final product. While these swaps won’t break the recipe, you will get a different final product than I did.

• As I’ve provided this recipe in percentages as well as grams you can easily calculate it to any size using a simple spreadsheet as I’ve explained in this post. As written in grams this recipe will make 100g.
• To learn more about the ingredients used in this formulation, including why they’re included and what you can substitute them with, please visit the Humblebee & Me Encyclopedia. It doesn’t have everything in it yet, but there’s lots of good information there! If I have not given a specific substitution suggestion in this list please look up the ingredient in the encyclopedia before asking.
• If you’d like to learn more about the surfactants used and compare them to ones you might already have so you can make substitutions, check out this page and read this FAQ.
• You can replace the hyaluronic acid with more distilled water if you don’t have hyaluronic acid.
• You can use any hydrosol you want, or simply replace it with distilled water for an unscented final product.
• Glycerin will work instead of propanediol 1,3.
• Do not replace the Glyceryl Stearate (and) PEG-100 Stearate.
• For the coco caprylate:
  • My first choices for alternatives would be other ultralight emollients like C12-15 alkyl benzoate or Neossance® Hemisqualane.
  • If you don’t have anything like that you could try a really lightweight oil like Rosehip Oil, Camellia Seed Oil, or Olive Squalane.
• You’ll need some sort of gelling agent to keep this formulation stable. If you don’t have Polyacrylate crosspolymer-6 (Sepimax ZEN), Aristoflex AVC would be my first choice for an alternative. You could also try hydroxyethylcellulose. Xanthan gum and other gums might work, but remember that the skin feel of the gum will definitely be noticable in the finished product. Regardless of what you use, if it’s not Polyacrylate crosspolymer-6 (Sepimax ZEN) please be potentially prepared to test and adjust the formulation for stability.
• If you’re like to use a different preservative, please review this FAQ and this chart.
• You could replace the cyclomethicone with more coco caprylate or a natural cyclomethicone alternative.
• If you’d like to incorporate an essential oil, please read this.
• It should be possible to make something like this using sucrose stearate instead of Glyceryl Stearate (and) PEG-100 Stearate for a natural option. Check out this formulation from Skin Chakra for some guidance.