Article by: Perry Romanowski

The sunscreen market is a growing one and to be a competent cosmetic chemist, you should know the basics of how to formulate one.

How a sunscreens work

A sunscreen is typically a skin lotion with added UV blockers or absorbers.  UV exposure from the sun has a number of negative impacts on skin such as burning, wrinkle causing and cancer.  So, sunscreens are designed to protect from these.  There are two ways in which they can work.  First, they have ingredients that block or reflect sunlight.  Second, they have compounds that absorb sunlight and convert it to a less harmful energy like heat.  These sunscreens are oil-soluble or disperseable so emulsions are excellent delivery vehicles.  Sunscreens are also available in gel and aerosol forms but we’ll save those types for another post.

When a sunscreen lotion is put on the skin, it forms a continuous film which provides protection from UV rays.  Ideally, this film will spread easily and will be resistant to wash-off.

Sunscreen ingredients

In the United States, sunscreens are classified as OTC drugs and are regulated by the FDA.  Accordingly, there are a limited number of approved sunscreen active ingredients.  You can find a complete list of approved sunscreens in the FDA sunscreen monograph.  For our purposes, we’ll just mention a few of the more common actives; Titanium Dioxide, Zinc Oxide, Avobenzone, Benzophenone 8, Octocrylene, and Oxybenzone.  To vary the amount of sun protection, the level of the active ingredient is adjusted.

Moisturizing ingredients

The most common moisturizing ingredients are occlusive agents which create a barrier that blocks water from escaping the skin.  Ingredients like Petrolatum, Mineral Oil and Dimethicone can all be used as occlusive agents.  Humectants, which are ingredients that attract water, are also added to lotions.  Glycerin is the most commonly used humectant.  Finally, emollients are added to improve the feel of the lotion on the skin.  They can reduce the tackiness and greasiness caused by the other moisturizing ingredients.  Common emollients include coconut oil, cetyl esters, and certain silicones.  Sunscreen formulations are typically thinner in viscosity than standard skin lotions.

Other ingredients

In addition to the moisturizers, sunscreens contain emulsifiers to make the oil and water compatible.  There are suspending agents, neutralizing agents and thickeners.  Finally, to make it a complete and stable formula raw materials such as fragrance, preservative, and colorants are also included.

Here is a typical sunscreen formula.

Click on image to enlarge it.



About the Author

Perry Romanowski

Perry has been formulating cosmetic products and inventing solutions to solve consumer problems since the early 1990’s. Additionally, he has written and edited numerous articles and books, taught continuing education classes for industry scientists, and developed successful websites. His latest book is Beginning Cosmetic Chemistry 3rd Edition published by Allured.


  1. Avatar

    Who do you recommend to approve an existing formula for FDA compliance?

    1. Avatar
      Perry Romanowski

      Just make sure the product is safe (doing stability testing and safety testing). Also, you’ll need to comply with FDA GMP requirements.

  2. Avatar
    Drake Blessum

    Hi Perry,
    Your article was very helpful. I am at the start of creating an affordable sunblock and was hoping we could connect. I would be happy to email or call you when ever you would have a few minutes to discuss how to start the sunblock formulation process.
    Thank you in advance for helping a stranger.

    1. Avatar
      Perry Romanowski

      I fixed it

  3. Avatar

    hi formula is not displaying do u have a copy

    1. Avatar
      Perry Romanowski

      I’m still trying to get it updated.

  4. Avatar

    What about adding in other oils like Coconut oil, Aloe, Shea Butter, Papaya (Papaya) Fruit Extract, others, etc?

    1. Avatar
      Perry Romanowski

      You can if you want to.

      1. Avatar

        Thanks…is there a recommended process for adding in these oils, or can they be added in at any stage? Just trying to understand the process, thanks!

        1. Avatar
          Perry Romanowski

          These ingredients would be added to the oil phase and mixed together when the system is hot and forming the emulsion.

  5. Avatar

    what about sesame oil as a sun block agents?

    1. Avatar

      It’s not recommended. If you want to block UV rays you need a standard sunscreen ingredient like Titanium Dioxide or Zinc oxide

  6. Avatar

    when does item #10 come in?

    1. Avatar

      Add it at the same time as #11

  7. Avatar
    Kume Maximus

    Am impressed with the information , but will like to broaden the knowledge gotten

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