We’ve spent the last couple weeks learning how to formulate a simple, natural lotion, and how to adjust its viscosity, richness, scent, and more. Today we’re looking at the huge topic of how to start incorporating other ingredients like actives, botanical extracts, esters, and vitamins.

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Just a reminder; this post is part of my ongoing free series on natural lotion formulation. Here are the other parts:

1. Easy Natural Lotion for Beginners
2. How to gently scent lotions with natural ingredients (+2 free formulas!)
3. How to naturally scent lotions with essential oils and natural fragrance oils
4. How to make your lotions thicker
5. How to make your lotion richer
6. How to make your lotion lighter

This post is not a completely comprehensive guide—that would be impossible! But it will teach you how to think through incorporating new ingredients + how to adjust your formulations, and should leave you feeling confident to try new things 😊

The key to everything

Ingredient research! You need to know your ingredients in order to work with them properly. This is important for both the ingredients you want to add to your formulation and the ingredients that are already in your formulation.

You can find most of the information you’ll need in the free Humblebee & Me DIY Encyclopedia; I recommend starting there 😊

I also highly recommend learning how to research your ingredients—what you need to know and where to find that information. I share tons of tips & tricks in these two posts:

• How to Research Your Ingredients: Part 1
• How to Research Your Ingredients: Part 2

To incorporate an ingredient into a formulation you’ll need to know:

• How much you can use (usage rates)
• Which phase it should go into
• Solubility: not just water or oil, but how soluble it is in that solvent. Is there a compatible (and ample amount) of solvent for the new ingredient in your formulation?
• If it is compatible with the rest of formulation (does it require a pH that doesn’t work with your preservative? Is its charge opposite of your emulsifier?)

Your suppliers should provide this information. If they don’t, consider shopping elsewhere.

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The base formulation

You can find the base formulation that we’ll be working with here. Please make sure you are familiar with it!

Considerations for this particular formulation

• Our emulsifier will fail if the pH of the formulation is too low; anything lower than 4 will probably separate.
• Our emulsifier is also negatively charged (anionic), so adding a positively charged ingredient (like Polyquaternium 10) could cause stability issues.
• Our humectant, sodium lactate, contains electrolytes, so you won’t want to add any ingredients that don’t work well with electrolytes.
• The preservative in this formulation, Euxyl™ k 903, works best in a pH range of 3–6, so you won’t be able to add ingredients that require a higher pH range without compromising the performance of the preservative or that new ingredient.
• You’ll want to keep your cool down phase to around 10% or less; too large of a cool down phase can compromise the stability of a hot-processed emulsion. This means you won’t be able to incorporate a lot of heat sensitive ingredients into this (or any hot-processed) lotion formulation.

Broadly speaking…

Most of the ingredients I love and work with frequently are pretty easy to incorporate into our formulations. It’s simply a matter of determining a suitable usage rate, adding it to the correct phase, and adjusting the water or oil in the formulation to keep things in balance. They’ll obviously change the formulation (that’s why we’re including them, after all!), but they are unlikely to cause anything to blow up, break down, or otherwise fail.

Here’s a rough breakdown of how challenging ingredients are to incorporate into our formulas; some by the broad category and some more specifically.

Easy

• Botanical extracts
• Most humectants (glycerin, propanediol, hyaluronic acid, etc.)
• Hydrosols
• Ceramides
• Panthenol
• Colloidal oatmeal
• Esters
• Carrier oils
• Butters
• Fatty thickeners
• N-Acetyl Glucosamine (NAG)
• Hydrolyzed proteins
• Tocopherol (Vitamin E)

A bit challenging

• High-electrolyte ingredients (sodium lactate, aloe, urea, foaming surfactants) if the formulation is sensitive to electrolytes
• Actives with some requirements: urea, semi-stable formats of vitamin C, niacinamide (Vitamin B3),
• Preservatives with semi-narrow functional pH ranges
• Allantoin; keep reading to learn more!
• Gums—depending on the formulation. Pretty easy with emulsions, but more challenging with surfactants.

More challenging; you’ll likely want to build your whole formulation around these

• High concentrations of AHAs and other chemical exfoliants
• Vitamin C (specifically Ascorbic acid, especially in hydrous formulations)
• Really expensive, delicate carrier oils you don’t want to heat at all

Not sure? Take a look at the sample formulations offered by your suppliers to see how they’re using an ingredient.

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Examples

Here are a few different examples of how to think through adding a new ingredient to your formulation—and how to do it.

You can apply these questions and this process to any ingredient to incorporate it into your formulations.

How to add panthenol to your formulation

1. Are there any compatibility issues?
   Nope; panthenol (Vitamin B5) is pretty easy going!
2. Decide how much to use.
   The usage rate for powdered panthenol (Vitamin B5) in skincare products is generally 1–5%, with the higher end of the range for more therapeutic applications. This sample formulation will be an everyday hand lotion, so I’ll go with 1.5%.
3. Add it to the correct phase, adjusting the emulsifier if necessary.
   Powdered panthenol (Vitamin B5) is heat stable and water soluble, so I’ll add it to the heated water phase. No emulsifier adjustment required.
4. Reduce the amount of water in the formulation to keep the formulation adding up to 100%
   Drop the water by 1.5% to keep the formulation balanced.
5. Make your new formulation and see what you think!

Formulation with panthenol

Everyday Hand Lotion

Heated water phase
72.5g | 72.5% distilled water
5g | 5% sodium lactate (USA / Canada)
1.5g | 1.5% panthenol powder (vitamin B5) (USA / Canada)

Heated oil phase
5g | 5% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% sunflower seed oil (USA / Canada / UK / NZ)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)

For full instructions, please read this post.

How to add allantoin to your formulation

1. Are there any compatibility issues?
   Nope; allantoin gets along with everything in this formulation.
2. Decide how much to use.
   The usage rate for allantoin is 0.1–2%, but we also need to remember that allantoin isn’t very water soluble. It’s only about 0.5% soluble in water, so if we try to include 2% allantoin in this formulation we might encounter issues getting it to fully dissolve. I like to calculate the amount of allantoin I include in a formulation by how much water there is to ensure it’ll dissolve without issues. In this formulation we’ve got 74% water; if your formulation includes mostly-water ingredients like aloe vera juice or hydrosols, include them in that total. 74% x 0.5% = 0.37%. I’d round that down to 0.35% for a rounder number and a bit of a margin of error.
3. Add it to the correct phase, adjusting the emulsifier if necessary.
   I like to include allantoin in the cool down phase to prevent potential re-crystallization, though it is heat stable. I’ve never had issues with it dissolving in the cool down phase (or feeling shardy in the finished formulation) when added to the cool down phase and calculated to ensure there’s enough solvent. LotionCrafter recommends adding it to the cool down phase if you’re using it above the solvent calculation level. “Addition of Allantoin at 0.5% or more or at temperatures above 50°C (122°F) in aqueous systems can cause solubilization and recrystallization upon cooling into larger particles which are perceptible during product use.”
4. Reduce the amount of water in the formulation to keep the formulation adding up to 100%
   Drop the water by 0.35% to keep the formulation balanced, resulting in 73.65% distilled water
5. Make your new formulation and see what you think!

Formulation with allantoin

Skin-Softening Lotion

Heated water phase
73.65g | 73.65% distilled water
5g | 5% sodium lactate (USA / Canada)

Heated oil phase
5g | 5% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% fractionated coconut oil (USA / Canada)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)
0.35g | 0.35% allantoin (USA / Canada)

For full instructions, please read this post.

How to add lactic acid to your formulation

1. Are there any compatibility issues?
   Yes. If you want to add lactic acid to a formulation at a level where it will function as a chemical exfoliant, the final pH will need to be around 3.86. This will not work with our emulsifier, so you cannot add an active skincare level of lactic acid to this formulation as it will split. You could try it with a different emulsifier that has a broader effective pH range, but for the purposes of this post I’ll stop here since we can’t add lactic acid to this formulation.

How to add niacinamide to your formulation

1. Are there any compatibility issues?
   Nope Niacinamide (Vitamin B3) won’t react with anything in this formulation. We will want the final pH to be in the 4–6 range, which works with our emulsifier and preservative.
2. Decide how much to use.
   The usage range for niacinamide (Vitamin B3) is about 2–6%. Let’s choose something middle-ish and go with 3%.
3. Add it to the correct phase, adjusting the emulsifier if necessary.
   Niacinamide (Vitamin B3) is water soluble, and can be included in the heated phase. No emulsifier adjustment is required as this ingredient is water soluble.
4. Reduce the amount of water in the formulation to keep the formulation adding up to 100%
   Drop the water by 3% to keep the formulation balanced.
5. Make your new formulation and check the pH, adjusting as required.
6. Enjoy!

Formulation with niacinamide (Vitamin B3)

Everyday Hand Lotion

Heated water phase
71g | 71% distilled water
5g | 5% sodium lactate (USA / Canada)
3g | 3% niacinamide (vitamin B3) (USA / Canada)

Heated oil phase
5g | 5% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% sunflower seed oil (USA / Canada / UK / NZ)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)

For full instructions, please read this post.

How to add calendula extract to your formulation

1. Are there any compatibility issues?
   Since “extracts” are a wide category, let’s take a look at the specific one we’re using: Bramble Berry’s Calendula Extract. Start by taking a look at the INCI to determine the solubility. The INCI is “Caprylic Triglyceride, Calendula Officinalis Flower Extract”, so we know it’s oil soluble. Since we have an oil and a water phase we know this will work with our formulation, and there’s nothing else to worry about with this ingredient.
2. Decide how much to use.
   Bramble Berry suggests up to 6%. Let’s do 4% for this sample formulation.
3. Add it to the correct phase, adjusting the emulsifier if necessary.
   Extracts go in the cool down phase, so that’s where this one will go. This will make for a cool down phase that’s 5%; that’s ok.Since it is an oil base, we’ll need to consider adjusting the emulsion. We have a couple options: 1) swap some of the Medium Chain Triglycerides in the formulation for the extract (this keeps the oil phase the same size);  2) ensure there’s enough emulsifier to accommodate the addition of an additional 4% oil (this will increase the size of the oil phase), 3) increase the amount of emulsifier (this will increase the size of the oil phase even more than option 2).In this formulation I know there’s enough emulsifier to accommodate the addition of another 4% oil, so I won’t change the emulsifier or the amount of liquid oil in the formula and I’m simply add the extract to the cool down phase. Learn more about how much emulsifier is required for how much oil with this post.
4. Reduce the amount of water in the formulation to keep the formulation adding up to 100%
   Drop the water by 4% to keep the formulation balanced.
5. Make your new formulation and check the pH, adjusting as required.
6. Enjoy!

Formulation with calendula extract

Natural Calendula Lotion

Heated water phase
70g | 70% distilled water
5g | 5% sodium lactate (USA / Canada)

Heated oil phase
5g | 5% Ritamulse SCG (USA / Canada / UK / AU)
15g | 15% sunflower seed oil (USA / Canada / UK / NZ)

Cool down phase
1g | 1% Euxyl™ k 903 (USA / EU)
4g | 4% oil-based calendula extract

For full instructions, please read this post.

Now what?

Once you’ve made your new, modified lotion, test it out and see what you think! Most ingredients you’ll want to add to your formulations will do well the first time, but some are a bit more tricky and it can take a while for something to go a bit cattywampus.

If you notice colour changes, separation, viscosity changes, spoilage, scent changes, or pH drift, that’s a sign that something you added needs to be re-visited. You might need to use less, include a buffer to keep the pH in check, adjust the emulsifier, include a chelator… there’s lots of options and possibilities. That’s a big part of the fun of formulating!

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