The two stars of this formulation are niacinamide (Vitamin B3) and hyaluronic acid; two of my favourite skin care ingredients. They team up with fragrant sweetgrass hydrosol and a few other functional ingredients to create a simple, hydrating, brightening facial serum that’s a lovely addition to your skincare routine.

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I first tried niacinamide (Vitamin B3) in The Ordinary’s Niacinamide 10% + Zinc 1% serum back in 2018, and it was practically magic for my skin. Within a week of starting to use it I noticed I was getting fewer pimples and lingering red marks left behind by old ones were fading. Niacinamide has been an absolute staple in my skin care routine ever since.

Hyaluronic acid also played a large role in the improvement of my skin as I learned about and fully embraced the importance of topical hydration. I learned that my skin needed lots of added water to thrive; simply using anhydrous moisturizers wasn’t enough. Hyaluronic acid is one of my favourite humectants—especially in facial products—because it’s effective and it feels beautiful on the skin.

I’ve included a hefty glug of sweetgrass hydrosol (a 40% glug, to be precise) to scent the serum. I adore sweetgrass hydrosol; it smells like sunshine on long, dry prairie grass in the summer. It smells like home, sunshine-y dog walks, and fresh air. If you don’t have sweetgrass hydrosol you could easily use a different hydrosol instead. You could also use aloe vera juice instead, witch hazel, more distilled water, or a blend. Have fun with it!

The rest of the ingredients in this formulation are functional ones. Liquid Germall™ Plus to preserve, a drop of 90% lactic acid solution to drop the pH to about 5.75, soft xanthan gum to add a wee bit of body, propanediol 1,3 to disperse that xanthan gum into (+ boost moisturizing properties & preservative efficacy), and distilled water to bring the whole thing up to 100%. All in all, it’s a pretty simple formulation.

Save 20% on soft xanthan gum and everything else at Formulator Sample Shop with coupon code HUMBLEBEE

I packaged mine in a dropper top bottle, though earlier versions went into some wee bottles with treatment pump caps and those worked well, too. Enjoy!

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Relevant links & further reading

Brightening Hyaluronic Acid & Niacinamide Facial Serum

1.5g | 3% Propanediol 1,3 (USA / Canada)
0.25g | 0.5% Liquid Germall Plus™ (USA / Canada)
0.05g | 0.1% xanthan gum (soft) (USA / Canada)

15.665g | 31.33% distilled water
0.035g | 0.07% 90% lactic acid solution (USA / Canada)
20g | 40% sweetgrass hydrosol
10g | 20% low molecular weight 1% hyaluronic acid solution (USA / Canada / New Zealand)
2.5g | 5% niacinamide (vitamin B3) (USA / Canada)

Weigh the propanediol, Liquid Germall™ Plus, and xanthan gum into a small beaker. Stir to combine.

Add the remaining ingredients and stir. Cover and leave the solution to fully dissolve and become uniform.

Once the solution is clear, it’s time to test 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?). Check the pH with your pH meter (I have this one [USA / Canada]). 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 come out to 5.5–6, which is great! I’d say anything in the 5–6 range is fine. If yours is outside that range, please read this article to learn more about pH adjusting.

Once you know your formulation is a-ok in the pH department, it’s time to package it up! I used a 60mL (2 fl oz) glass bottle with a dropper top from YellowBee for mine (gifted). It looks like they don’t sell that size anymore, but they do have a 50mL bottle (and top) that would work even better for this 50g (1.76oz) batch.

To use; I like to spread a few drops over my skin after cleansing and then follow up with a cream or oil serum. Enjoy!


Because this formulation 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.


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 50g.
  • 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.
  • You could try glycerine instead of propanediol 1,3.
  • If you’re like to use a different preservative, please review this FAQ and this chart.
  • You can use regular xanthan gum instead of soft xanthan gum. You could also use a different gum; there’s so little of it that the precise one isn’t vitally important. You could also leave the gum out (replacing it with more water); this will result in a slightly thinner finished formulation.
  • You could use a different acid to adjust the pH, but you will have to do your own testing and adjusting to determine the amount required.
  • You can use a different hydrosol for a different scent.
  • If you’d like to incorporate an essential oil, please read this.
  • I do not recommend swapping out the hyaluronic acid or niacinamide (Vitamin B3) as both are essential/integral to the formulation.

Gifting Disclosure

The glass dropper bottle was gifted by YellowBee.
The sweetgrass hydrosol was gifted by Plant’s Power.
The xanthan gum (soft) was gifted by Formulator Sample Shop.
The hyaluronic acid was gifted by Pure Nature.
Links to Amazon are affiliate links.