Is Walnut Scrub Bad for Your Skin? The St. Ives Lawsuit, Microtears and What Actually Matters

Updated September 2026

Walnut scrub isn't automatically bad for your skin, but it can irritate if the particles are coarse, you press hard, you use it too often, or you use it on skin that doesn't tolerate scrubbing. Most of the "microtears" worry traces back to a 2016 lawsuit over a face scrub, which a federal court dismissed in 2018 because the plaintiffs didn't prove the product harmed skin. On body skin, used with light pressure and followed by moisturizer, a walnut shell scrub is a reasonable option if physical exfoliation agrees with you.

Full disclosure: we make Becky Booty Scrub, which uses walnut shell powder, so we have a stake in this question. We've tried to answer it straight and show our sources.

Is walnut scrub bad for your skin?

Walnut shell powder is a physical exfoliant: ground shell particles that lift dead skin as you massage. Every physical exfoliant is abrasive by design. That's how it works, whether the particles come from walnut shells, sugar, salt or pumice.

So the useful question isn't "is walnut bad?" but "is this scrub, used this way, right for my skin?" That comes down to a few things:

• The particles: their size, shape and how many there are.
• The formula the particles sit in.
• How you use it: pressure, time and frequency.
• Your skin: where you're using it and how reactive it is.

On that last point, the American Academy of Dermatology (AAD) says people with dry, sensitive or acne-prone skin may prefer a washcloth and a mild chemical exfoliant, since mechanical exfoliation may be too irritating. It also advises avoiding strong mechanical or chemical exfoliation if you have a darker skin tone or tend to get dark spots after irritation.

Where did the "walnut scrubs cause microtears" idea come from?

The claim got its biggest spotlight from a class action against Unilever over St. Ives Apricot Scrub, a facial scrub that contains crushed walnut shell. Here's what happened, based on Truth in Advertising's case file and a summary of the ruling from law firm Proskauer:

• December 2016: The case, Browning v. Unilever United States, Inc., was filed in federal court in the Central District of California.
• The allegations: The plaintiffs said the walnut shell in the scrub caused tiny tears in the skin that could lead to problems like acne, infection and moisture loss. They also challenged the product's "dermatologist tested" and "non-comedogenic" labels.
• December 2018: The judge granted Unilever's motion for summary judgment and dismissed the claims.
• The reasoning: The court found the plaintiffs hadn't shown the scrub was a safety hazard or that it caused the harm they described. Proskauer notes the plaintiffs' expert study involved 15 people over two weeks, too little to show long-term effects. The court also observed that an exfoliant is necessarily abrasive.

What the case does and doesn't tell you: the dismissal isn't a scientific finding that walnut scrubs are gentle. It means the plaintiffs didn't prove their case. It also isn't evidence that walnut shell damages skin. The lawsuit made the microtear idea famous without settling it, and we didn't find good published research that settles it either.

Why does face vs body matter?

The walnut debate has almost always been about face scrubs, and that context matters.

• Facial skin is more delicate, especially around the eyes, than skin on your butt and thighs.
• The face is where most people use retinoids, acids and benzoyl peroxide. The AAD notes these can make skin more sensitive or prone to peeling, so adding a scrub on top raises the odds of irritation.
• Acne and redness-prone skin are common on the face, and those are exactly the skin types the AAD steers toward milder exfoliation.
• Body skin isn't invincible. Butt and thigh skin can still get irritated, shaving-sensitive or bumpy, so the same "gentle" rules apply.

The practical takeaway: use a body scrub on your body, not your face.

What makes a physical scrub gentle or harsh?

A quick test: rub a little of the scrub between your fingertips and on your inner forearm. If it feels sharp or scratchy there, it will feel that way on your butt too.

Here's how we formulated Becky Booty Scrub, so you can judge for yourself. Its walnut shell powder sits in a rinse-off, sulfate-free cleansing base with aloe leaf juice, glycerin, provitamin B5, vitamin E, oatstraw extract, and jojoba, rosehip and sunflower seed oils. It's fragrance-free and made for the butt and body, not the face. Those are formulation choices, not a clinical gentleness claim: how you use any scrub matters just as much.

Who should avoid walnut shell scrubs?

• People with a tree-nut allergy. Walnut shell comes from a tree nut. Skip walnut scrubs, or ask your allergist first.
• People who avoid wheat. This one is specific to Becky: it contains hydrolyzed wheat protein. It also contains coconut-derived cleansers.
• Anyone with broken, sunburned, freshly waxed or irritated skin, or an active rash or eczema flare in the area.
• People using prescription retinoids, retinol or benzoyl peroxide on the same skin, per the AAD.
• People with dry, very sensitive or acne-prone skin that reacts to scrubs. A mild chemical exfoliant may suit you better.
• People with darker skin who get dark spots after irritation. If you do use a scrub, keep pressure very light and sessions infrequent.
• People with red, irritated keratosis pilaris. The AAD's KP self-care guidance warns that scrubbing tends to irritate skin and worsen KP.

If your skin reacts easily in general, our sensitive-skin butt care routine is a better starting point than any scrub.

How do you use a walnut scrub without irritation?

1. Patch test first. Try a little on a small area and wait a day before using it more widely.
2. Wet your skin with lukewarm water.
3. Use a small scoop mixed with a little water in your palm.
4. Massage in small, light circles with your fingertips for about 30 seconds per area. Let the particles do the work.
5. Rinse well with lukewarm, not hot, water, as the AAD recommends.
6. Pat dry and moisturize right away. The AAD notes exfoliating can be drying.
7. Start once a week. Increase to two or three times only if your skin stays comfortable.
8. Stop if you notice redness, stinging, burning or peeling, and give your skin a break.

For a fuller walkthrough, including shaving days, see how to use a body scrub.

Walnut vs sugar vs salt vs acids: how do they compare?

No exfoliant is automatically safe or harsh. A sugar scrub rubbed hard every day can irritate more than a walnut scrub used lightly once a week, and a strong acid can sting more than either. If you're weighing scrubs against acids, see physical vs chemical exfoliation, and for scrub picks, our best butt scrubs of 2026.

FAQ

Can walnut scrub cause micro-tears?

Any physical exfoliant can irritate or scratch skin if the particles are rough or you scrub hard. The idea that walnut scrubs specifically cause microtears became famous through the St. Ives lawsuit, but the court found the plaintiffs hadn't proven harm, and we didn't find published research settling it. The practical answer: choose a fine texture, use light pressure and stop if skin gets red or sore.

Is walnut scrub safe to use on the butt and thighs?

For most people whose skin tolerates scrubs, yes, as long as the skin is intact and you use light pressure. Skip it on broken, freshly waxed or irritated skin, and follow with moisturizer. Keep face and body scrubs separate.

How often should you use a walnut scrub?

Start once a week. If your skin stays comfortable, two or three times a week is a common ceiling. The AAD's rule is that the more aggressive the exfoliation, the less often you should do it.

Is walnut scrub bad for acne-prone skin?

It can be too much. The AAD notes mechanical exfoliation may be too irritating for acne-prone skin and suggests a mild chemical exfoliant instead. Many people with body breakouts do better with a salicylic acid wash. See body acne treatments dermatologists actually use.

Can you use a walnut scrub if you have a nut allergy?

Don't use one without talking to your allergist first. Walnut shell comes from a tree nut, and allergic reactions to skin products can show up as itchy, red rashes. If you've already had a reaction, stop using the product and contact a healthcare professional.