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Let’s Talk Humidity


Firstly, in my opinion, controlling your temperature is more important than your humidity, BUT, the correct humidity is still vital to getting the best out of your adhesive.

Secondly, there is no such thing as an adhesive that works better than another in different environmental conditions. It’s simply what works better for the individual.

Now that bit is out of the way, for those that are interested in the science behind all this glorious weather and its relationship with lash adhesives, read on…

I’d like to start with what humidity is and why as a lash artist you need to know about it.

Humidity is the amount of water vapour in the air. This is important to lash artists because humidity/moisture is the catalyst for setting lash adhesives. When “humidity” is mentioned in relation to lash adhesive, they are referring to RELATIVE HUMIDITY (RH). Here is the definition of RH: The amount of water vapour present in air expressed as a percentage of the amount needed for saturation at the same temperature. In lamens terms, how full the air is of moisture.

Did you know that hot air can hold more water vapour/moisture than cold air? This is why it’s likely that when your temperature rises, the relative humidity % lowers.

Now that I’ve briefly explained RH, here’s how it affects lash adhesive…

Too low in relative humidity will slow everything down and your adhesives will take longer to cure which can also lead to sensitisation as the vapours are looking for moisture and are naturally attracted to the moisture around the eyes and nose. Basically, you are more likely to have reaction like symptoms in low humidity.

If humidity is too high it can cause shock polymerisation of the adhesive. This ‘shock’ polymerisation can lead to a shrinking process of the adhesive layer and weaker bonds. basically, poor retention.

The ideal RH for life, in general, is 40-60%. Any higher or lower means better conditions for bacteria and nasty stuff to grow. This goes the same for lashing and your own comfort.

Here’s a controversial one for you… There is no such thing as a lash adhesive that works in a wide range of humidities! Don’t fall for any marketing that suggests otherwise!

Lash adhesives best conditions for lash application is between 20-24C room temperature and 55% RH with good air movement / local extraction at the point of application. FACT.

So if your favourite adhesive isn’t working like it used to then you have 3 options.

1. Get your conditions under control.

2. Adjust your technique.

And if option 1 and 2 just aren’t for you then your final option is:

3. Get a slower/faster adhesive.

Just don’t go asking for adhesives that work in high/low humidity levels etc.

The changes in environmental conditions should not mean that you have to frantically search for a new adhesive. If you know your stuff and can adapt, these weather changes will never be an issue for you again.

Thanks for reading!

Written by: @LashBase_Jamie (Instagram)