The Missing Ingredient in Many Aromatherapy and Herbal Formulations: Antioxidant

As aromatherapists and herbal formulators, we often focus on the beautiful natural ingredients that bring our products to life — essential oils, herb-infused oils and butters, aloe gel, and botanical extracts.

But one important ingredient that is frequently overlooked is an antioxidant.

This wasn’t something I learned in my aromatherapy training, but it was emphasized during my cosmetic chemistry education — and for good reason.

Why Antioxidants Matter in Natural Formulation

Antioxidants play a vital role in protecting essential oils, carrier oils, and butters from oxidation, helping our formulations remain fresh, stable, and effective for longer.

When oils oxidize, a chain reaction occurs that alters their chemical composition. Here’s why that’s a problem:

• For essential oils: Oxidation can increase the risk of skin irritation and change the product’s aroma and color.

• For carrier oils and butters: Oxidation leads to rancidity, unpleasant odor, and a loss of the nourishing properties we value in these ingredients.

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Simply put — oxidation can compromise both the safety and quality of your products.

Best Antioxidants to Use in Skincare and Aromatherapy Formulations

Two of the most accessible and effective antioxidants for formulators are Vitamin E (tocopherol) and rosemary oleoresin extract (ROE).

1. Vitamin E (Tocopherol)

Vitamin E is a fat-soluble antioxidant made up of eight naturally occurring compounds — alpha, beta, delta, epsilon, eta, gamma, and zeta tocopherols, plus four related substances known as tocotrienols.

While each offers unique biological activity, d-alpha tocopherol is considered the most active form.

Common types of Vitamin E used in formulation include:

• d-alpha tocopherol (natural)

• dl-tocopherol (synthetic)

• Mixed tocopherols (50–95%)

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These can be used in small amounts to protect your oils from oxidation and to deliver skin-nourishing benefits.

However, note that dl-tocopherol acetate (Vitamin E acetate) — though great for the skin — does not function as an antioxidant in formulations. If you use Vitamin E acetate, you’ll still need to include a true antioxidant to stabilize your oils and butters.

Typical usage rates:

• Mixed tocopherols T50 (50%): 0.5–1.5% of the oil phase

• Mixed tocopherols 95%: 0.25–0.75% of the oil phase

  
  

2. Rosemary Oleoresin Extract (ROE)

Rosemary oleoresin is a thick, brownish-green extract derived from the rosemary plant. Its strong antioxidant power comes primarily from carnosic acid, one of its key constituents.

ROE is available in various concentrations and can help prevent rancidity in carrier oils and extend the shelf life of your formulations.

Typical usage rate: 0.02–0.1%

Antioxidants vs. Preservatives — What’s the Difference?

It’s important to remember that antioxidants are not preservatives.

• Antioxidants protect your product from oxidation — they slow down rancidity and degradation of oils.

• Preservatives, on the other hand, protect your product from microbial growth — bacteria, mold, and fungi.

  
  

If your product is oil-based and contains no water, you typically don’t need a preservative (microbes need water to grow).

However, if you’re formulating lotions, creams, gels, or other water-based products, you’ll need a broad-spectrum preservative system to prevent microbial contamination.

That’s a topic for another post — but it’s an essential part of safe and professional formulation.

Final Thoughts

If you want your handcrafted skincare and aromatherapy creations to stay fresh, effective, and safe, incorporating antioxidants is a must. They’re your first line of defense against oxidation, helping you maintain product integrity, prevent off-odors, and protect your clients’ skin.

Want to dive deeper into formulation science?

Check out this excellent video from the Institute of Personal Care Science, or Contact me to book a discovery call and learn how to bring your formulations to the next level.

Aromatic blessings,Tricia