Any product with water in it (which is most products) is a buffet for mold, yeast, and bacteria the moment you open the jar. Preservatives aren't optional — they're the difference between a safe product and a contaminated one.
Why "natural" preservation is so hard
Plant-derived antimicrobials like rosemary extract or essential oils do have some antimicrobial activity, but it's usually narrow-spectrum — strong against certain microbes, useless against others. Relying on them alone often means under-preserving the product, which is a real safety risk, not a marketing win.
What synthetic actually buys you
Ingredients like phenoxyethanol or the parabens were chosen by formulators precisely because they're broad-spectrum, stable across a wide pH and temperature range, and effective at low concentrations. "Synthetic" here just means "designed for the job," not "more toxic."
A product that's beautifully "clean" on the label but grows mold in three weeks isn't safer for your skin — it's just a different kind of risk.
What I actually check for
Instead of natural vs. synthetic, I look at concentration and combination. Most well-formulated products use a system of two or more preservatives working together, each covering the others' weak spots. That's a much better signal of a thoughtfully made product than any single buzzword on the front of the bottle.