Stress balls, also known as squeeze balls or relief balls, have become an increasingly popular desk accessory and stress relief toy. These soft, squishy balls are meant to be squeezed when one is feeling anxious, angry, or in need of a quick distraction. The repeated motion of squeezing can help relieve muscle tension and anxiety.
Stress balls come in all shapes, sizes, and materials, but many are filled with some type of liquid or moldable material enclosed in an outer layer made of rubber, silicone or textured plastic. One of the most common fillers for stress balls is slime – that sticky, gooey, slippery substance kids have been playing with and getting all over everything for decades. But is slime safe for regular handling and contact with skin? And are the dyes and other additives potentially toxic?
What’s in Slime?
Basic slime consists of just two main ingredients – glue and borax. The Elmer’s brand white glue found in most craft aisles is a popular choice, along with bottled glue marketed as “slime glue” or “slime activator”. Borax is a mineral powder that acts as a cross-linker to turn the glue into a stretchy, moldable putty. Some recipes also incorporate liquid starch, saline solution, or rubbing alcohol to achieve different textures.
For stress balls and other commercial slime products, manufacturers use more complex recipes and often replace borax with other safe cross-linking chemicals. Additional ingredients like softening agents, preservatives, fragrance oils, and artificial coloring are added to give the slime a smooth, pleasant texture and appearance. High-end slime products may include “beads, glitters, foam balls, and other whimsical mix-ins to increase sensory stimulation and enjoyment.
Are the Ingredients Toxic?
Borax has gotten a bad reputation because boric acid, which can be derived from borax, is toxic if ingested in large amounts. However, the small amounts of borax used in homemade slime recipes are not considered toxic for kids or adults. The Consumer Product Safety Commission states that borax is safe if used appropriately. As long as you don’t eat your slime or get it in your eyes, homemade slime with borax should not cause any health issues from regular contact with skin.
The other main slime ingredients – glue, starch, saline, glycerin, and rubbing alcohol – are all non-toxic. Artificial dyes and fragrances may cause allergic skin reactions in some individuals, but these are rare. Glitters and plastic beads mixed into some slime can be a choking hazard for small children, so supervision is recommended. As with any product, check the manufacturer’s label for any specific cautions.
Off-gassing of VOCs
Some parents and consumer groups have raised concerns that stress balls and slime products contain phthalates added to soften the vinyl and increase pliability. Phthalates help the slime keep its shape instead of slowly spreading out and hardening over time. However, phthalates are endocrine disruptors and should be avoided in children’s toys if possible.
Slime products may also release small amounts of volatile organic compounds (VOCs) like phenol, formaldehyde, and toluene as they slightly break down and off-gas over time. Studies have found higher levels of VOCs coming from homemade slime using white glue compared to commercial slime products. While the VOC exposure from occasionally playing with slime is minimal, prolonged or frequent use may raise indoor air quality concerns especially for young children.
Making Safer Slime
For those concerned about potential chemical exposures from store-bought slime, it’s easy to make your own version using natural, non-toxic ingredients:
- Use psyllium husk powder instead of borax
- Substitute natural cornstarch, chia seeds, or clay for thickeners
- Add a few drops of natural food coloring
- Use 100% natural fragrance oils
- Mix in natural add-ins like oats, seeds, dried flowers or herbs
You can also purchase high quality slime from reputable toy companies that avoid phthalates, VOCs, and other harsh additives. Or explore alternative stress ball fillers like sand, beads, or even modeling clay.
While standard slime and stress ball ingredients are considered safe for most people, it’s smart to read labels and monitor for skin reactions. Make sure young kids don’t put slime near eyes or mouth. With just a little care and caution, you can feel good about enjoying all the squeezing, squishing, and sensory stimulation these popular toys provide!