How to avoid getting lost in preservatives and antioxidants

(and why your cream sometimes lasts a month… and sometimes just a week)

Making cosmetics at home is a joy. You mix cream, shampoo or tonic… and suddenly you feel like you're holding a small miracle in your hands.

But then reality sets in:

“Yesterday the cream was great… and today it smells weird.”

And it's usually not the recipe's fault.
The difference between "it works perfectly" and "I'd rather throw this away" is almost always:

• aqueous phase
• hygiene in production
• cover
• proper preservation

Why is water such a problem in cosmetics?

As soon as water appears in a product (or hydrolate, aloe gel, herbal decoction, floral water…), you open the door to microorganisms.

Water = ideal environment for bacteria, yeast and mold.

Regardless of whether you use natural or synthetic raw materials.

That's why there are preservatives in cosmetics.

What about anhydrous products?

Oils, balms, butters and oil serums are usually not spoiled by microbes, but they are mainly threatened by:

• oxidation (yellowing)
• contamination from fingers
• humidity from the bathroom

You're not looking for preservative here, but antioxidant.

What do you actually have to deal with in cosmetics?

In every recipe, there are three basic "players":

1) Preservatives (broad spectrum)

Their job is to protect aquatic products from:

• bacteria
• by yeast
• mold

Used in:

• cream
• in shampoos
• shower gels
• tonics
• gels and emulsions

2) Boosters (support of the preservation system)

They are not the main preservative, but:

• increase the efficiency of preservation
• improve recipe stability
• function as a system fuse

It is usually not enough on its own.

3) Antioxidants (oil protection)

Does not address microorganisms.

Protecting oil and butter from:

• oxidation
• by gulping
• by changing the smell and color

Quick decision-making trick

Is there water in the product?

Yes → you need preservative (often also booster)

No → preservative usually not, but antioxidant

Don't want to deal with the complexities?

Usually one proven broad-spectrum preservative.

Do you measure pH?

Yes → you have more choice

No → choose preservatives less sensitive to pH

Overview of the most common preservatives

Preservatives are substances that protect a cosmetic product containing water from the growth of microorganisms. It's not just about keeping the product from "turning sour" or smelling bad - microbial contamination can lead to the degradation of active ingredients and, in extreme cases, skin irritation.

Each preservative has its own specifics: different pH range, different strength, different method of use. There is no one universal preservative ideal for everything, but some are significantly more practical for home production than others.

Cosgard / Geogard 221

Cosgard (also known as Geogard 221) is one of the most used preservatives in home cosmetics because it offers a good compromise between effectiveness, ease of use and versatility.

It is a broad-spectrum preservative that works against:

• bacteria
• yeast
• mold

When to use it:

• if you want one preservative usable for most recipes
• if you don't want to complicatedly combine multiple ingredients
• when you are just starting out with cosmetics production

Suitable for:

• creams and emulsions
• skin and body tonic
• gely
• shampoos and shower gels

Practical notes:

• works best in acidic to slightly acidic pH
• added in the colder phase, usually at the very end of production
• may have a slight typical preservative smell, but this is usually lost in the product

Leucidal (fermentation preservation system)

Leucidal is a preservative of fermentation origin, based on radish fermentation products. It is often sought after by those who want to work with the most natural ingredients possible.

Its main strength lies in its effect against bacteria.

Important restrictions:

Leucidal is not a fully broad-spectrum preservative.

• its effectiveness against yeasts and molds is limited
• on its own does not provide sufficient protection for most cosmetic products

Therefore, in practice it is almost always combined with other components, most often with:

Sodium Levulinate & Sodium Anisate (Preservative 1388 ECO)

This combination significantly expands the spectrum of protection and increases the safety of the product.

When to use it:

• if you want fermentation-based preservation
• when you count on combined preservation system

Take into account that:

• often requires higher dosage
• its effectiveness is more sensitive to the composition of the recipe
• without the addition of an additional preservative, the risk of spoilage is higher

If you want worry-free preservation and no need to combine, it is usually better to choose a stronger (often partially synthetic) preservative.

Benzoate + Sorbate

The combination of sodium benzoate and potassium sorbate is one of the classic preservative systems used primarily in aqueous and acidic products.

Their effectiveness is strongly dependent on the pH of the product.

Suitable for:

• skin and hair tonic
• water gels
• light emulsions

AMTicide Coconut

AMTicide Coconut is a naturally derived preservative based on coconut oil. It excels in its good effectiveness against bacteria and fungi and fits well into naturally tuned formulas.

It is used either as part of a wider preservative system, or as a strengthening ingredient for other preservatives, especially where you want to increase protection without fundamentally altering the character of the recipe.

Suitable for:

• creams and emulsions
• tonics and gels
• shampoos and shower gels

Practical notes:

• works well in combinations (e.g. with 1388 ECO or Leucidal)
• helps to expand the spectrum of action towards yeasts and molds
• is suitable for natural and gentle cosmetics

If the product is anhydrous, you are mainly dealing with oxidation.

Vitamin E (tocopherol)

Most common antioxidant.

Suitable for:

• oil serums
• balms
• oil phase of creams

Important:

will not replace a preservative in aquatic products

Rosemary extract

antioxidant for oils and butters

Applies again:

antioxidant ≠ preservative

Sodium Gluconate

Sodium gluconate is one of the auxiliary ingredients for preservation that are used in home and professional cosmetics to increase stability and safety of formulas.

This is not a classic preservative - it does not destroy microorganisms by itself, but significantly supports the effectiveness of the preservation system.

It is a so-called chelating agent that binds metal ions contained in water (e.g. calcium, magnesium, iron). Thanks to this:

• improves the effectiveness of preservatives
• helps prevent product spoilage
• increases the long-term stability of cosmetics
• reduces changes in color, odor and texture

Sodium gluconate is often added to creams, serums, toners, shampoos and shower gels as a preservative booster, especially in combination with natural or pH-limited preservatives.

Important:
Sodium gluconate is not a full-fledged preservative and is always used together with a preservative, not alone.

Practical tips at the end

• If you're doing something with water and don't want to complicate it, start with Cosgard.
• If you use benzoate/sorbate or 1388 ECO, count on pH measurement.
• Booster is a great insurance, but it does not replace the main preservative.
• For pure oil products use antioxidant, not preservative.
• Preservative is not magic, hygiene, packaging and storage are equally important.

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