"Preservative-free" sounds like a good thing. It sounds pure, clean, and natural. But here's something most people don't realize: in skin care, a product without any preservation system isn't safer — it's actually a health risk.
At Aquinas Soap Company, we use natural preservatives in our water-containing products — and we're completely transparent about why.
Why Preservatives Are Necessary
Any product that contains water — or comes into contact with water during use — can support the growth of bacteria, mold, and yeast. This includes lotions, creams, liquid soaps, toners, and many other skin care products. Without a preservation system, these products can become contaminated within days to weeks of being made, even if they look and smell perfectly fine.
Applying a contaminated product to your skin — especially to broken or sensitive skin — can cause serious infections. The preservatives in skin care products are there to protect you, not harm you.
Note: anhydrous (water-free) products like bar soaps, solid balms, and bath bombs don't require preservatives because there's no water present for microbes to grow. That's why our bar soaps are preservative-free by nature.
Why Not Just Use Synthetic Preservatives?
The most common synthetic preservatives — parabens (methylparaben, propylparaben, butylparaben) — are effective, but there is ongoing and legitimate debate about their potential to disrupt hormones. While regulatory bodies consider them safe at current usage levels, we'd rather not use them when effective natural alternatives exist.
Other synthetic preservatives like formaldehyde-releasing agents (such as DMDM hydantoin or imidazolidinyl urea) are even more contentious — they work by slowly releasing small amounts of formaldehyde to prevent microbial growth. Again, considered safe at low levels, but not something we want in our products.
What Natural Preservatives Do We Use?
We rely on a small number of well-researched, naturally-derived preservation systems depending on the product:
- Vitamin E (Tocopherol) — a powerful antioxidant that prevents oils from going rancid. Used in oil-based products and as a supporting ingredient in broader preservation systems.
- Rosemary Extract (Rosmarinus officinalis) — another natural antioxidant that extends the shelf life of oil-rich formulas.
- Leucidal® Liquid (fermented radish root) — a naturally-derived, broad-spectrum preservative produced through fermentation. Effective against bacteria and yeast, with an excellent safety profile.
- Naticide® — a naturally-derived preservative with a pleasant almond-like scent, effective against a broad range of microorganisms.
The specific preservative we use depends on the formula — water content, pH, and other ingredients all affect which system works best.
Do Natural Preservatives Work as Well?
Yes — when chosen correctly for the formula and used at the right concentration. This is where small-batch, handcrafted production makes a real difference. We formulate each product carefully, test for stability, and ensure our preservation system is appropriate for that specific formula. A mass producer running thousands of units can't give that kind of attention to each product.
Shorter Shelf Life — A Feature, Not a Bug
Natural preservatives generally result in a shorter shelf life than synthetic alternatives — typically 12 to 18 months, compared to 2 to 3 years for heavily preserved commercial products. We see this as a positive: it means you're using fresh products made with active, potent ingredients, not something that sat in a warehouse for two years before reaching you.
We always include a best-before date on our products so you know exactly what you're working with.
Our Commitment to Transparency
We list every ingredient on every product — including our preservatives — because we believe you have the right to know exactly what you're putting on your skin. No hidden blends, no vague terms. Just honest formulation, every time.
Have questions about a specific product's ingredients? Reach out to us — we're always happy to talk formulation.