This cold-processed face serum does a whole lot of awesome things: it hydrates, brightens, reduces fine lines, evens out skin tone, boosts barrier function, soothes, softens, and might also know exactly which mango in that display at the grocery store will taste the best (no promises about that last one, though 😝). If you watched my recent ingredient deep-dive into niacinamide and have been thinking you should make something awesome with it, I think this Brighten & Boost Facial Serum is a fabulous choice!

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The bulk of this Brighten & Boost Facial Serum is a blend of watery things. A hydrosol of choice (or blend!) scents the formulation; I chose rose hydrosol because I love it. I think a citrus hydrosol (perhaps a blend of citrus and rose!) would be really lovely—let your nose and your heart guide you. If you prefer an unscented formulation you can easily replace the hydrosol with more distilled water.

For some silky, luxurious hydration I’ve included 0.2% low molecular weight hyaluronic acid in the form of a 1% solution used at 20%. If your hyaluronic acid is a different weight you could use that instead—just keep in mind that different weights of hyaluronic acid penetrate the skin differently. Learn more here!

I’ve selected a suite of some of my favourite actives for this formulation, focussing on brightening, boosting barrier function, reducing transepidermal water loss (TEWL), and moisturizing.

A blend of niacinamide (Vitamin B3) and N-Acetyl Glucosamine (NAG) are the stars of the actives blend. These two ingredients are a powerful brightening duo, but they do so much more! They also bring anti-inflammatory, barrier-boosting, fine-line-reducing, ceramide-production-increasing, TEWL-reducing, skin-renewing wonders to this formulation. I love these two ingredients! If you are vegan you should double check the source of your NAG, as it can be derived from the shells of crustaceans.

Skin-soothing and moisturizing panthenol (Vitamin B5), softening and anti-inflammatory allantoin, and moisturizing and conditioning betaine round out our bouquet of actives.

The last category of ingredients in this formulation is the functional ingredients; these ingredients aren’t super exciting, but they improve and/or stabilize the formulation. I’ve included small percentages of each soft xanthan gum and polyquaternium 10 to add a wee bit of viscosity and body to the formulation. I got the idea to include some polyquaternium 10 from La Roche-Posay’s Effaclar Ultra Concentrated Serum. This serum includes a wee bit of polyquaternium 10—right before the fragrance—and the product has a really indulgent, silky skin feel. I thought I’d give it a try, and I like it! Soft xanthan gum is a heck of a lot nicer than regular xanthan gum; if you’re using regular xanthan I’d use half as much. And another note—if you often find formulations tacky, you’ll probably want to half the soft xanthan gum. The end formulation will be a bit thinner, but it’s also a bit less tacky.

I’ve included two low-tack humectants to compliment the hyaluronic acid—propanediol 1,3 and sodium lactate. These boost the hydrating, moisturizing qualities of the formulation and give us some fluid to pre-disperse the xanthan gum and polyquaternium 10 in. A small amount of PEG dimethicone helps reduce tackiness, and Liquid Germall Plus preserves the whole formulation. A small amount of lactic acid lowers the pH of the formulation a bit. I made this formulation the first time with a bottle of hydrosol that had been open for a while, and later versions with a fresh bottle of hydrosol. That first batch had a pH of 5.45, while subsequent batches with the fresher hydrosol were around 5.7. Both are totally fine for this formulation 😊 The longer your hydrosols (and distilled water) have been open, the lower the pH will be as that water absorbs CO₂ from air (cool, eh?).

Making this formulation is simple; simply stir the ingredients together in approximately the right order (as long as you pre-distribute the thickening powders in the non-watery wet things first it’s hard to go wrong), cover, and let everything dissolve. Check the pH, bottle it up, and you’re off to the races!

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Relevant links & further reading

• Xanthan Gum in the Humblebee & Me Encyclopedia
• Propanediol 1,3 in the Humblebee & Me Encyclopedia
• Sodium Lactate in the Humblebee & Me Encyclopedia
• Liquid Germall Plus in the Humblebee & Me Encyclopedia
• Distilled water in the Humblebee & Me Encyclopedia
• Hyaluronic Acid in the Humblebee & Me Encyclopedia
• Allantoin in the Humblebee & Me Encyclopedia
• Niacinamide (Vitamin B3) in the Humblebee & Me Encyclopedia
• N-Acetyl Glucosamine (NAG) in the Humblebee & Me Encyclopedia
• Panthenol (Vitamin B5) in the Humblebee & Me Encyclopedia
• What’s up with hydrosols, distillates, and floral waters?
• Ten Projects to Make with Hyaluronic Acid + HA Q&A
• Let’s Talk About Hyaluronic Acid
• How long will ______ last? What is its shelf life?
• Can I use a different preservative than the one you’ve used?
• pH
  • pH meter in the Humblebee & Me Encyclopedia
  • pH measurement in cosmetic lab: why we dilute samples? from Skin Chakra
  • How to adjust the pH of your cosmetic products from Skin Chakra
  • Why do you create a 10% dilution of a formulation before measuring the pH?
• Similar skincare formulations:
  • Hyaluronic Acid B5 Facial Serum
  • Skin Brightening Toner Mist
  • Brightening Gel Serum
  • Soothing Hyaluronic Acid Facial Serum
  • Silky Soothing Facial Gel
• HOW to add NIACINAMIDE to your formulations (and WHY!) | Vitamin B3 ingredient deep dive (video)

Brighten & Boost Facial Serum

0.36g | 0.2% xanthan gum (soft) (USA)
0.18g | 0.1% Polyquaternium-10 (USA / AUS)
5.4g | 3% Propanediol 1,3 (USA / Canada)
7.2g | 4% sodium lactate (USA / Canada)
0.9g | 0.5% Liquid Germall Plus™ (USA / Canada)
3.6g | 2% PEG-8 Dimethicone (USA)

26.514g | 14.73% distilled water
72g | 40% rose hydrosol (USA / Canada)
36g | 20% low molecular weight 1% hyaluronic acid solution (USA / Canada / New Zealand)
0.126g | 0.07% 90% lactic acid solution (USA / Canada)

0.72g | 0.4% allantoin (USA / Canada)
9g | 5% niacinamide (vitamin B3) (USA / Canada)
9g | 5% N-Acetyl Glucosamine (USA / Canada)
3.6g | 2% betaine (USA / Canada / EU)
5.4g | 3% panthenol powder (vitamin B5) (USA / Canada)

Weigh the xanthan gum and polyquaternium 10 into the propanediol, sodium lactate, Liquid Germall™ Plus, and PEG-8 dimethicone into a beaker. Stir until uniform.

Add the water, hydrosol, hyaluronic acid solution, and lactic acid. Stir to combine.

Add the allantoin, niacinamide (Vitamin B3), N-Acetyl Glucosamine, betaine, and panthenol (Vitamin B5). Stir to combine, and then cover the beaker and leave it for a couple hours to allow the ingredients to dissolve.

When you can no longer see any white powder in the serum and it has noticeably thickened into a serumy consistency, we’re ready to check the pH.

To test and adjust the pH: create a 10% dilution by weighing 2g product and 18g distilled water into a small bowl or beaker and whisk to combine (wondering why we create a dilution to check the pH?). Check the pH with your pH meter. Depending on the shape of your bowl/beaker you may need to tilt it in order to fully submerge the sensor on your pH meter. The pH should fall in the 5.25–5.75 range. If it is lower than 4.5 you’ll want to raise it; if it’s higher than 6, you’ll want to lower it. Please read this article from Skin Chakra to learn more about pH adjusting.

Once you know the pH is in a good place, it’s time to package up the serum. I recommend a bottle with a dropper, treatment pump, or orifice reducing cap. The 180g batch specified here will fill three 60mL (2 fl oz) bottles; the ones I used are from Amazon.

To use: pat a few drops into your skin after cleansing, but before creams and facial oils. I use this formulation morning and night. Enjoy!

Shelf Life & Storage

Because this serum contains water, you must include a broad-spectrum preservative to ward off microbial growth. This is non-optional. With good manufacturing practice and proper preservation, this formulation should last at least a year. 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 formulation 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 180g, which will fill three 60mL (2 fl oz) bottles.
• 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.
• If you don’t have soft xanthan gum you can use regular xanthan gum instead, though I’d only use half as much.
• If you don’t have polyquaternium 10 you can replace it with more xanthan gum. You could also try cationic guar gum as an alternative.
• You could try replacing the Propanediol 1,3 with propylene glycol, more sodium lactate, sodium PCA, or Vegetable Glycerin (though that could be a bit tacky).
• You could replace the Sodium Lactate with Propanediol 1,3, propylene glycol, sodium PCA, or Vegetable Glycerin (though that could be a bit tacky).
• If you’re like to use a different preservative, please review this FAQ and this chart.
• If you don’t have PEG-8 dimethicone, see if you can find a different PEG silicone. It must be a PEG silicone or it will just float on top of the serum. If you cannot find any PEG silicones you can replace it with more distilled water, though this will make for a tackier finished serum.
• You can use any hydrosol you like the scent of.
• You can replace the 1% LMW hyaluronic acid solution with:
  • A 1% hyaluronic acid solution of a different weight
  • 10% Hyaluronic Acid 4D and 10% distilled water
  • 3–5% sodium lactate and 15–17% distilled water
• You can use a different acid to adjust the pH. Citric acid would be an easy choice, though how much you’ll need will almost certainly vary.
• A water soluble comfrey root extract could work as an alternative to allantoin, though you’ll likely need more as if won’t be as concentrated. Refer to supplier documentation for guidance.
• If you don’t have Niacinamide (Vitamin B3) or N-Acetyl Glucosamine (NAG) you could replace either with a plant extract of choice (or a blend). Pisum Sativum (Pea) Extract would be a good option for brightening; calendula would be a good option for soothing benefits.
• You could replace betaine with more Sodium Lactate.
• You could replace Panthenol (Vitamin B5) with more sodium lactate, a hydrolyzed protein, or a soothing plant extract.
• If you’d like to incorporate an essential oil, please read this.