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The Problem Hiding in Plain Sight
Grab a silicone teether from your baby’s toy bin right now. It probably looks fine — smooth, colorful, maybe a little chewed at the edges. But the surface appearance of a silicone product tells you almost nothing about what’s actually inside it.
Silicone is not a single, uniform material. The quality varies enormously depending on how it was manufactured, what fillers were added during production, and which curing process was used. Low-grade silicone may contain fillers, leaving it sticky, oily, or with a chemical smell — and these materials are harder to clean and may degrade faster. For a product going directly into a baby’s mouth for hours at a time, that distinction matters.
The good news: there are two practical tests you can do at home in under a minute that tell you a lot about what you’re working with.
The Stretch Test (Also Called the Pinch Test)
This is the most widely used at-home method for detecting fillers in silicone. Here is how to do it correctly:
Find a thin section of the teether — a narrow arm, a textured ridge, or any area where the silicone is relatively thin and flexible. Thicker sections require considerably more force and can give you a false pass.
Grip and stretch firmly. Using your thumb and forefinger, pinch and twist the silicone with real force — not a light squeeze. Pull it laterally if the shape allows. You are looking for any color change in the stretched zone.
Watch the color. Pure, high-quality silicone should maintain its color when stretched. If the stretched area turns white, you are likely holding silicone that contains chemical fillers. The physics behind this is straightforward: because of its structure, pure silicone absorbs light and appears consistent in color. Fillers added to silicone do not have the same light-absorbing properties, so they scatter light — and that scattering is the white you see when you stretch.
One important nuance: silicone with precipitated silica as a filler will turn white when stretched or twisted due to strain whitening, while silicone made with fumed silica tends not to. This means the test is most reliably interpreted as an indicator of lower-grade filler content, not an absolute pass/fail for safety. Thicker silicone items like cups and plates need more force to see the fillers, whereas a thinner product can be lightly stretched to reveal impurities. Apply that same logic to a teether: test the thinnest part you can find.
And repeat the stretch in two or three spots. A product might pass in one area and fail in another if the manufacturing was inconsistent.
The Smell and Visual Inspection
The stretch test works best paired with a simple smell and look-over. These two checks catch different problems.
Smell it first, before stretching. High-quality silicone should be odorless. A strong chemical smell may indicate the use of fillers or low-grade materials. If a pungent odor is detected, it is not food grade. If there is a plastic smell, it may contain PVC or unqualified materials. Even a faint petroleum or chemical note is worth taking seriously on something a baby will chew on for months.
Look at the surface carefully. Run your finger along the teether. Low-grade silicone may feel sticky or oily to the touch, even when clean and dry. That tackiness is often a sign of residual peroxide byproducts from cheap curing processes, or of filler migration to the surface over time.
Check the color consistency. Look for any uneven pigmentation, blotchy patches, or areas where the color appears faded near seams or edges. These can suggest inconsistent mixing during manufacturing — which often goes hand in hand with lower material quality.
Inspect the construction. Teethers with one-piece construction are safer than multi-piece designs. A single piece minimizes the risk of choking hazards and ensures there are no small parts that could break off. If the teether has painted-on colors rather than colors molded into the silicone itself, that is a separate concern worth noting — surface-applied pigments can chip or flake.
What the Tests Can and Cannot Tell You
These at-home methods are genuinely useful screening tools, but they have real limits worth understanding.
The pinch test is not an official method for determining compliance with FDA standards and should not be relied upon as the sole basis for determining safety. It does not detect heavy metals, BPA migration, or residual peroxide from the curing process. It cannot confirm whether a product meets CPSC or CPSIA requirements. What it does reliably flag is the presence of certain lower-grade fillers — which is a meaningful data point, but not the whole picture.
There is also a nuance around the “food safe” label that many parents do not know: “food safe” silicone can still have fillers in it, as long as those fillers stay beneath levels set by FDA testing requirements. A product can legally carry an FDA food-safe designation and still turn white on the stretch test. So passing FDA testing is a floor, not a ceiling.
For a more complete picture, look for products that carry third-party certifications such as FDA food-grade compliance, CPSIA certification, or LFGB (the German standard that is generally considered stricter than FDA because it does not allow fillers in food-contact silicone). Ask the brand directly whether they can share third-party lab reports. Reputable manufacturers generally have these on file and are willing to share them.
Applying This to What You Already Own
If you run the stretch test on a teether and it turns white, the practical question is what to do next. A failed stretch test does not automatically mean a product is dangerous — it means the silicone contains a higher level of fillers than premium-grade material would. Whether those fillers pose a risk depends on what they are and at what concentration, which you cannot determine at home.
A reasonable approach: if a teether fails the stretch test and has a noticeable chemical smell, retire it. If it fails the stretch test but is otherwise odorless and certified by a recognizable safety body (CPSC, CPSIA), the risk is lower — though you may still prefer to replace it with something you have more confidence in.
When shopping for a new teether, look for brands that are transparent about their silicone sourcing and willing to state that their products are free of BPA, PVC, phthalates, lead, and cadmium. Loulou Lollipop’s silicone teethers, for example, are made from 100% food-grade silicone and are free of BPA, PVC, phthalates, lead, and cadmium, while exceeding US CPSC and CPSIA safety requirements. Their inks are water-based and food-safe, injected into the silicone rather than applied on top — which addresses the surface-pigment concern directly. You can browse their full teether collection to see the range of shapes and textures available.
The stretch test takes about thirty seconds. It is imperfect, but it is a lot better than nothing — and for a product that spends hours in your baby’s mouth, thirty seconds of due diligence is well worth it.