Formulate a Niacinamide and Liquorice Serum

Here's where I got a couple of the harder-to-find bits. I haven't linked everything, just the ones that can be a faff to track down:

• Dipotassium Glycyrrhizate

• Zemea Propanediol

Method

1. Weigh the water in a beaker.

2. In another beaker, mix propanediol with Solagum AX to form a slurry. Add this slurry to the water.

3. Add in the Olivem 1000 and Coco-caprylate.

4. Heat Phase A to 75°C. (To clarify: gum, water, emulsifier, and oil are in one beaker.)

5. Remove from the heat and homogenise until smooth. Move on to stirring by hand.

6. At temperatures below 40°C, add Phase B one by one and stir until homogeneous.

7. Add Phase C and adjust pH to be 5.8-6.3 (Phase D).

Wait 24 hours before evaluating.

I used a 5% Neroli essential oil blend as my essential oil.

A gel-cream serum looks dead simple sitting in its bottle, but there's a fair bit of proper formulation tucked into it. Here's what you're really practising:

Making a one-pot emulsion– heating the water and oil phases together in a single beaker is the gentlest introduction to emulsions there is. You get a real, stable result without the stress of matching two separate phases to the same temperature, which is exactly the bit that trips people up early on.

Pre-dispersing a gum– making a slurry with the propanediol before the gum ever touches water is the small habit that separates a smooth gel from a lumpy one. Tip a gum straight into water, and you'll be fishing out little jelly bits for ages; wet it first, and it behaves. You'll use this trick in almost every gel you ever make.

Homogenising, then stirring by hand– high shear from the homogeniser gives you that fine, even texture, and switching to gentle hand-stirring as it cools keeps you from whipping air into it. Knowing when to swap from one to the other is a real bit of judgement, and it comes with practice.

Adding actives at cool-down– this is where the why of temperature finally clicks. Niacinamide and essential oils don't want cooking, so they wait until the emulsion drops below 40°C, once the hard structural work is done.

Adjusting the final pH– checking and correcting the pH at the end isn't optional. It keeps the serum kind to your skin and keeps the niacinamide stable. Get into the habit now, and it'll be second nature by the time your formulas get more involved.

Get those five comfortable, and you've picked up the bones of most leave-on creams and lotions without really noticing. Different ingredients next time, but the same handful of moves.

The niacinamide percentage is the first dial I'd play with, depending on how your skin responds.

Niacinamide 5% to 2 or 3%– drop it down if your skin is on the sensitive side or completely new to the active. You'll trade a little of the effect for an easier ride, and you can always creep it back up once you know how you get on. Just top up the water to keep everything at 100%.

Coco-Caprylate/Caprate to squalane or Caprylic/Capric Triglyceride– both are light emollients that keep things from feeling heavy. Squalane has a slightly silkier slip, and I do love it, while Caprylic/Capric Triglyceride sits a touch more matte. Keep the percentage the same and see which you prefer.

Dipotassium Glycyrrhizate to bisabolol or allantoin– if you fancy a different soothing active, bisabolol is gorgeous for calming, and allantoin is a dependable, gentle conditioner. They each bring their own character, so it's worth running them against the liquorice to see which your skin likes best.

Essential oil to your own blend, or none at all– leave it out entirely for reactive skin, no harm done, or build your own scent. If you're not sure which oils sit well together in a leave-on serum, or what's safe at this sort of percentage, Fiona, our AI Lab Assistant, will happily help you put a blend together.

The whole point is that once you understand what each ingredient is there for, the formula becomes something you can read rather than just follow, and any swap you make comes with a clear idea of what it'll do.

SAFETY NOTE

This one's a leave-on, so it stays on your skin and needs a bit more care than a rinse-off would. Niacinamide at 5% is well tolerated by most people, but if you've not used it before, bring it in slowly and keep an eye on how your skin responds.

If you're adding an essential oil, do check the IFRA guidance for leave-on products, as the safe levels are stricter than for anything you rinse straight off. Patch test the finished serum on the inside of your forearm and give it a good 24 hours before you trust it on your face.

Buy from suppliers you trust and hang on to their paperwork, the COA, and for any fragrance, the IFRA certificate and allergen list. You'll be glad of it if you ever take a formula further, and it's good practice anyway.

This blog is for educational purposes only and is not intended to replace cosmetic safety assessments required for commercial sales.

If this is one of your first emulsions, I think you'll be surprised by how much the one-pot method takes the fear out of it, and you'll come away with something you'll want to use. Once it feels familiar, that same method opens up a whole shelf of light creams and serums, with this niacinamide formula as a solid base to refer to.

If you give it a go, I'd love to know how you find the one-pot approach, especially if you've been making anhydrous products and this is your first water-based formula. Come and tell us about it over in the Lab Notes Society, our free community, where there's always someone happy to talk a formula through with you.