Overpreserving - as Bad as Underpreserving

Everyone knows what happens when a cosmetic product is under-preserved. It goes bad. It might not be immediately detectable, but eventually a change in the scent, color, or even visible mould growth happens. Regardless of how it goes bad, the outcome is the same: a bacteria-riddled product that is unsafe for use.

I'm pretty sure we agree underpreserving is bad news all around.

And I totally understand why some choose to 'stay on the safe side' when preserving their cosmetics.

After all, preservatives are toxic.

Preservatives are Toxic

Yup. Really.

Well, they have to be. They have a pretty important job. Preservatives have to keep bacteria, fungus, and mould at bay without otherwise compromising the product.

Let me repeat that last part: without otherwise compromising the product.

In short, a correctly dosed preservative keeps the product safe for use for the extent of its shelf life. 

Preserving Cosmetics - a Question of Balance

Preservatives are supposed to be toxic – but only to the unwanted organisms that would happily take up residence in a cream, lotion, or face mask.

It's a question of balance.

Working with preservatives is tricky, demanding, and requires experience, so it's not surprising a lot of DIY skincare makers are uncomfortable working with them.

The devil is in the dose, and the dose has to be just so.

A preservative is not the kind of ingredient where you can 'wing it' when it comes to type or dosage. The amount added – when it is added – and which preservative functions best is specific to each formula.

It's definitely not the kind of ingredient where you can add 'an extra dash to preserve even better'.

It just doesn't work like that.

Overpreserving is Not on the Safe Side

Every time I hear a DIY'er mention adding preservative to a formula that does not require preservative or says they add a little extra  'just to be on the safe side', I cringe and recall the unfortunate incidents of skin burn and rash I have seen happen to folks who believed they were doing right by overdosing the preservative.

Adding extra (or unnecessary) preservative 'to be on the safe side' achieves exactly the opposite.

That 'extra dash' turns the product into a potential danger for the user – because too many toxins have been added. Seeing someone experience burns all over their face from an overpreserved product leaves a memorable impression.

Overpreserving is everything but being on the safe side.

So How Can We Know? Work Like a Pro. 

Although there is no reliable 'cheat sheet' on choosing and dosing preservatives, I will leave you with this tip: start with manufacturer guidelines and study the options before choosing a preservative for your product.

Consider the pH, production method, how and when the preservative is added (at cool-down, heated phase, etc) and whether or not the preservative risks reacting with some of the other ingredients in your formula.

If the preservative you decide to use has a recommended dosage range, try doing several small batches with different dosages before finalizing your formula.

Finally, when you think your formula is ready for bigger batches, send your product to a lab for stability and challenge testing.

It's not just for your own safety, but for the safety of the customers who will be using your products.

The Natural Preservatives

If you're interested in learning a bit about some of natural preservatives available on the market today, my colleague at Formulators Kitchen and I have put together a free e-book about preservatives with manufacturer information that you can download right here.

Be safe!


Ieva said…
Very good point, as always. I'm making things only for myself and even then don't want to risk an over/under preserved product for my face. Hands and body skin can handle way more potential mistakes :D
LisaLise said…
HI Leva- Thanks for your kind words! A lot of folks have a love/hate relationship with preservatives, but then it's kind of understandable too. It saddens me when I see people getting hurt because of misinformation and misguidance.