Walnut Shells: A Powerful Body Scrub and the Micro-Tear Debate

Active Ingredients Glossary · W

INCI: Juglans Regia (Walnut) Shell Powder

Ground walnut shells are among the coarser natural exfoliants. They're harder than sugar and don't dissolve. This makes them effective on rough areas of the body—and explains why they came under criticism a few years ago. Here's what you need to know about the micro-tear debate and how to use them effectively.

What is walnut shell powder?

To make the powder, the hard shells of the walnut (Juglans regia) are dried and ground. In the INCI list, it is listed as Juglans Regia (Walnut) Shell Powder. It is a byproduct of walnut processing, biodegradable, and has become popular, among other things, as an alternative to microplastic beads, which have been banned from rinse-off cosmetics in many countries.

How effectively the powder exfoliates depends primarily on the grind: finely ground particles feel more like fine sand, while coarse pieces are angular and noticeably hard. In exfoliants, the particles are usually suspended in oils, butters, or shower gel, which cushion the friction.

Effect: What's Been Proven

Two out of five bars. It is undisputed that walnut shell powder mechanically removes dead skin cells, and the effect is immediately noticeable—the skin feels smoother. However, there are hardly any controlled studies on walnut scrubs, and the effect remains superficial.

Up for debate: In the mid-2010s, a class-action lawsuit was filed in the U.S. against a well-known facial scrub containing walnut shells. The allegation: The sharp-edged particles caused "micro-tears" in the skin. The lawsuit was unsuccessful in court, and the claim has not been scientifically proven. Nevertheless, there's a grain of truth to it: Hard, irregular particles can irritate the skin and strain its barrier when applied with too much pressure or used too frequently—especially on the thin skin of the face. The key factors are the fineness of the grind, the formulation, and your technique.

Application & Combination

Walnut shell scrubs belong on the body: on elbows, knees, feet, thighs, or buttocks. Apply them once or twice a week to damp skin, using light pressure in circular motions; rinse thoroughly and follow up with moisturizer. In exfoliating shower gels, the particles are embedded in a cleansing lotion, which usually feels gentler than a pure scrub. Avoid coarse shell scrubs on your face and opt for fine-grained products or mild acids instead.

Walnut shells in the BONSANA lineup

Frequently Asked Questions About Walnut Shells

Do walnut shells cause micro-tears in the skin?

There is no scientific evidence to support this. However, hard, sharp particles can cause irritation if too much pressure is applied or if used frequently, especially on the delicate skin of the face. When used on the body and applied gently, walnut shells are a proven body exfoliant.

Can I use a walnut scrub on my face?

Coarse walnut scrubs are intended for the body. For the face, very finely ground products or mild acids are the gentler choice.

How often should I exfoliate with walnut shells?

Once or twice a week is sufficient for the body. Apply to damp skin using light pressure, then moisturize afterward. Avoid irritated or freshly shaved areas.

Are walnut shells better than microplastics?

Walnut shell powder is a natural, biodegradable byproduct and is therefore the better choice for the environment than plastic beads. However, it has a slightly stronger effect on the skin than round beads.