Will My Skincare Products Go Bad If Left In The Heat?

heat and your skincare products

If you shop from our website, your order is shipped directly from our warehouse in Austin, Texas. If there are two words that describe Texas, it’s HOT SUMMERS (and fall, too!). This means that the box we ship to you may sit in a hot mail truck for hours and, depending on where you live, it might also sit on your doorstep in the heat. What if your cleanser or moisturizer is a thinner consistency when it first comes out of the box? Is it ruined? Will it be less effective?

The answer is no. If they’re formulated properly, heat should not affect the performance of your skincare products—let me explain why.

What Happens if Your Skincare Products Get Hot?

It’s important to know what goes into how a product is made. When products are made in a certified laboratory, chemists will do what is called the “oven test.” This is where a product is put into an oven with temperatures around 115 degrees Fahrenheit with 70 percent relative humidity. The products are kept in there anywhere from six weeks to three months. The purpose of the oven test is to determine whether a product can stay stable and maintain its integrity when exposed to heat. This is important since products can often be left in hot mail trucks or in less-than-desirable conditions. The oven test can also help determine the shelf life of a product by essentially creating a “time-lapse.” It tells us if a product will remain stable for a full two years and whether it’s normal for a formula to separate or change consistency during that time.

All Renée Rouleau products go through this oven test, exposing them to heat over long periods of time to ensure their safety, performance, and longevity. So rest assured that if your skincare products get hot, it won’t affect their efficacy at all.

Note: The oven test does not factor in UV light, so if a product sits out for long periods of time in UV light and is in clear, see-through packaging, this will most likely weaken the performance of ingredients such as antioxidants and UV filters in sunscreen (which tend to break down in light). So definitely keep your products in a closed cosmetic bag and try not to subject them to long periods in the sun.

Not All Skincare Products Are Made the Same Way

While most products made in a lab are held to rigorous standards, some products won’t be made to remain stable in heat. The type of skincare products that may not hold up in hot conditions include:

  • “All-natural” products
  • Small batch products that are meant to be refrigerated and used up quickly
  • Homemade products made in a kitchen that you might find on sites like Etsy

As I said, there is no guarantee that a product has undergone rigorous testing for stability. Keep this in mind or inquire about it before you make a purchase.

I can only speak for my own product line. When Renée Rouleau skincare products get hot, you don’t need to worry about their performance being affected. We’ve got you covered in all of life’s inevitable situations.

I hope you found this helpful! Want to learn more about products? Find out if your skin can get used to products and stop working which is a common question that I’m asked. If you’re interested in learning more about products, learn what product ingredient labels won’t tell you.


Post a comment
  1. Avatar

    I still have a question, I have some products from the sisley collection and they say it’s all natural! But I left it in my car and it hot overheated:(
    It smells a tiny bit off but can I still use it?

    Posted By: Chloe  | 

    • Renée Rouleau

      Hi Chloe, it’s hard for me to comment on other products since I am not involved in their formulation. I would reach out to Sisely’s customer support for the most accurate answer!

      Posted By: Renée Rouleau  | 

  2. Avatar

    PERFECT timing!!! I have been wondering about leaving products in my car…by accident of course!! : )

    Posted By: tracy  | 


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