Prepare your workspace: Ensure all utensils and surfaces are clean to avoid contamination.
You'll need a preferably glass container with an airtight lid for mixing, and a dark glass container like a dropper bottle for the final serum
Sprinkle the hyaluronic acid powder into the distilled water and cover with a lid - shake vigorously. It will still be clumpy. That's Ok.
Let it rest: Cover and refrigerate the mixture for about an hour, or until the hyaluronic acid has fully dissolved. Overnight is fine too.
If you are adding optional ingredients like vitamin e oil, do so after your primary mix is set, and stir until well combined.
Store the serum: Transfer the serum into a dark glass bottle with a dropper if desired, to protect it from light.
Store in the fridge for a week or two.
Look for discoloration or any change in smell. Make a new batch!
