Explaining the Viral Lavender Soap BookTok Theory

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Learn how the ‘Throne of Glass’ books inspired a TikTok trend

Co-authored by Raven Minyard, BA

Last Updated: January 5, 2026 Fact Checked

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What is the lavender soap theory?

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Origins of the Trend

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Applying the Theory

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Other TikTok Theories

If you’re a fan of TikTok (or Throne of Glass), you’ve probably come across videos of the lavender soap theory. Inspired by a character who regrets not letting her partner use her expensive soap, this theory encourages people to stop saving things for special occasions. Keep reading, as we explain what the lavender soap theory is, its bookish origins, and how to apply it to your own life.

Warning: Spoilers for the Throne of Glass series ahead.

The Lavender Soap Theory, Explained

The lavender soap theory is inspired by a scene in the book The Assassin’s Blade, in which a character regrets not letting her partner use her expensive lavender soap. The idea is that people should use and share the things that bring them joy as much as possible rather than saving them for a special occasion.

Section 1 of 4:

What is the lavender soap theory?

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The theory encourages people to use special items instead of saving them. The lavender soap theory began as a BookTok trend but quickly spread to TikTok as a whole. Inspired by Sarah J. Maas’s Throne of Glass book series, the theory encourages people to use all their best things—like expensive soap—as often as possible rather than saving them for special occasions. The idea is that the “right” time may never come, and you might regret not using the things that bring you joy.
- Creator @rio.mads posted a TikTok in a cool outfit and said, “Lavender soap theory: Was saving this Issey Miyake top for a special occasion, but would rather wear it now. Clothes are meant to be lived in.”
- @kythegoofygoober posted a video with the caption, “Letting my boyfriend use my Olaplex conditioner because of the lavender soap theory.”
- User @madisonlemon shared a video saying, “Letting my husband use the nice wrapping paper bc lavender soap.”

Section 2 of 4:

Origins of Lavender Soap Theory in Throne of Glass

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The lavender soap theory is inspired by the book series Throne of Glass. In The Assassin’s Blade, the prequel book to Sarah J. Maas’s popular Throne of Glass series, the main character, Celaena, doesn’t want her partner, Sam, to use her expensive lavender soap and instead makes him use a cheap soap. The next day, Sam dies on a mission, and Celaena regrets not letting him use the soap because that argument was the last conversation they had together.
- In the book, Maas writes, “The body still smelled faintly like Sam. And like the cheap soap she’d made him use, because she was so selfish that she couldn’t let him have her lavender soap.”^{[1]
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- Later in the series, Celaena, now going by her real name Aelin, allows her new partner Rowan to use her lavender soap, showing that she has grown as a character and deeply trusts Rowan.

Section 3 of 4:

Applying the Theory to Your Own Life

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As the lavender soap scene from Throne of Glass suggests, the “right occasion” may never come. Remember, the things you buy are meant to be used! Wear your best outfit on a regular Tuesday, use that fancy hand soap instead of a cheap one, and apply your expensive skincare every night. You don’t want to regret not using it later!
If you keep things pristine and don’t use them, you may miss a chance to enjoy them with your loved ones. Sure, your boyfriend or little sister may not understand how expensive a certain soap or skincare product is, but they may want to use it as a way to bond and share something with you.