Colin Sanders on Cosmetic Safety Assessment and Challenge Testing

I get a lot of questions from folks about the process of getting an artisan cosmetics product to market.

One area where confusion seems to abound is what Safety Assessment involves and how it differs from Challenge Testing, so I asked Colin Sanders of Colin's Cosmetics Consultancy to explain and he kindly agreed.

Please welcome Colin!

A lot of new entrepreneurs are unsure about what a Safety Assessment involves. Can you explain the process? What steps does a Safety Assessor go through and what should a client expect from them? 

The safety assessment arises from Annex I of the cosmetic regulations which requires that somebody with a suitable scientific background should assess the safety of the report and gives a set of things that they should consider.

Most people interpret this is requiring a written report, and most reports have structures that follow closely the layout of the annex.  But it is worth remembering that the regulation doesn't require a report to be written. It's the assessment itself that is the important bit.

I think a good way for an entrepreneur to look at it is that they are getting an expert's view of their product.   This could be quite valuable.  It is also worth remembering that the safety report is simply a record of the assessment.  It isn't an exam that has to be passed, and even if the conclusion is that the product is safe and marketable, it doesn't stop you making further improvements to it.

The process is generally that the assessor looks at your formulation, considers how it is going to be used and runs some calculations to make sure that the product doesn't pose any risk of causing harm to the end user under conditions of normal and foreseeable use.

As these things always do, quite a lot of customs and practice have grown up around safety assessments.  Some of these are quite sensible.  So you can reasonably expect an assessor to point out if the product breaches the regulations for example, even though that isn't one of the things that the assessor has to address according to Annex I.

They also generally check compliance with IFRA guidelines, even though these aren't even actually regulations - which can be very helpful in some cases.  Less justifiably, they sometimes assess the microbiological and stability data for its suitability.  This might be helpful in some cases, but it isn't always the best approach to put off the safety assessment until after a lot of time and money has been invested in the development.

One thing to bear in mind is that once something has been written it cannot be unwritten.  So for example, if your assessor puts in the report that a particular thing needs to be included in your warnings, you are going to need a really good reason to explain why you are not doing so.

It is a good thing to have a thorough assessor who checks everything out, but you are tied into whatever he or she comes up with.  When I was a technical manager and used to commission safety assessments regularly I would always prefer the assessors who would ring up to query something or discuss an issue to those who produced a thumping great report that I had to read through carefully to make sure it hadn't committed me to anything.

People sometimes confuse a Challenge Test with a Safety Assessment. Can you explain when a product ‘only’ needs Safety Assessment and when it needs a Challenge Test? Is it possible to have one without the other?

The two things aren't really that closely related in practice.  The challenge test comprises injecting the product, or 'challenging' it, with large quantities of germs and seeing how long they survive.  It's quite a tough test.  It was originally developed to prevent cross infections in hospital wards.

If your product meets the A criteria in the test, it is pretty much resistant to everything the microbial world can throw at it.

But you only need to test products that are prone to contamination.  Many aren't, and somebody has gone to the trouble of writing some notes on products that can be assumed to be non-risk from a microbiological point of view.  It is called ISO 29621 Microbiology -- Guidelines for the risk assessment and identification of microbiologically low-risk products.

But products always need to be assessed for safety even if ISO 29621 means you don't have to challenge them.

Please explain a bit about challenge testing - how long does a challenge test take and what steps does a product go through?

The challenge test takes 4 weeks.  The product is divided into sub samples which are injected with the five test organisms.

After 2, 7, 14 and 28 days, the number of test organisms still remaining is counted.  If they've gone down enough, you get an A criteria pass.

There is a slightly less stringent criteria called the B criteria.

Both grades of pass are good enough for cosmetic purposes.  In fact, if the standard were being written purely for cosmetic purposes, the pass rate would probably be set lower than it is.  But the standard was originally intended for pharmaceutical purposes.  It is probably too late to change things now though.

Is there any kind of reliable at-home testing for cosmetics products a client can do before contacting a Safety Assessor (or company for challenge testing)?

Unfortunately there isn't really anything like a challenge test that can be used as a proxy for it.   It is obviously encouraging if your product doesn't develop visible contamination when you leave it to stand for a few months - but given what a high gate the challenge test is to jump, it doesn't really help a great deal.

Is it common for a Safety Assessor to provide advice on, say, the formulation or the clients GMP, packaging or ingredients sources? In short, what of scope of help can one (within reason) expect of a Safety Assessor?

It varies a lot.  An assessor with a background in formulation is quite likely to offer advice.  Assessors who are primarily toxicologists don't really have the knowledge to help much.

Thank you Colin for your helpful insight!

Find Colin Sanders Here

Colin's Cosmetic Consultancy
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Formulators Kitchen


Hi Lise,
Great content as usual. I love reading your blog. Always interesting. Colin is a mine of info & very helpful.
I happened for fun, read some older posts, back to the sage posts. I remember those. ��
Keep well.
Sharon at the funny farm.
LisaLise said…
Hi Sharon -- So sorry for this tardy reply! Thank you kindly for your always lovely comments. Keep safe and healthy!