Info provided from humangear:
The GoToob+ is made of high-purity, FDA food-safe silicone. Silicone is one of the safest and most inert materials in common commercial use (heck, baby bottle nipples are made from the stuff!). It's not cheap material, but we decided to use silicone for the fantastic performance and safety it affords. However, no material is completely impervious. While the GoToob+ line works great with thousands of different fluids, sometimes a fluid can react, affecting the silicone of a tube, altering the fluid, or both. This is due to reactivity with silicone itself and isn't limited to the specific silicone we use for GoToob+. Also remember that the GoToob+ line is designed for travel, not long-term storage. Some products may change state (dry out or become less viscous) if kept in a GoToob+ for months at a time.
It is a good idea when using any product in a GoToob+ for the first time either to test a small amount overnight or to pack the GoToob+ in a leak proof bag for protection. We will happily replace your GoToob+ with a new one if there are any issues, but we can't say the same for whatever else you packed in your suitcase!
While the range of chemicals used in modern cosmetic and personal care products makes comprehensive compatibility testing impossible, we have consistently noticed problems with the following chemical groups/product types and recommend against using them in a GoToob+:
-Alcohols (Note: Alcohols may be present in many cosmetic products, including make-up remover, mouth wash, astringent, hair serum, aftershave, and insect repellent).
-Salicylic Acid (most often used in acne treatments).
-Hair serums and treatments (detanglers, relaxers, volumizers, polishers, smoothers, shine serums, etc.) including shampoos and conditioners designed to add shine or luster to hair as well as products with Argan Oil (like Moroccan hair oil).
-DEET-based insect repellents.
-Sterile products. Note: Even though sterile products may be fully compatible with silicone, GoToob+ are not sterilized. Therefore, we don't recommend GoToob+ for use with fluids where sterilization may be an issue, such as contact lens solution. This includes liquid or semi-liquid prescription medications.
-Caustic, corrosive, or flammable products. Note: Many household chemicals are sold in specifically designed plastic or glass containers specified by the manufacturer and should never be decanted. GoToob+ were designed for personal care or food items you may need while traveling--not bleach, drain cleaner, fire-starters, or hydrochloric acid.
Recommend Testing First
The following products are compatible with the GoToob+ in most cases. However, we've heard of problems in some cases when using these products and recommend testing a small amount in a GoToob+ overnight before general use or travel.
-Personal lubricants (non-silicone based).
-Liquid sweeteners (especially Stevia).
-Sunscreen and tanning lotions.
-Skin conditioning oil formulations.
Note: You will know if your fluid is incompatible if it leaks, changes the shape or color of the silicone tube, evaporates from the tube, or dries up shortly after being put in the tube. Most reactions occur overnight; this is why we recommend an overnight trial run with a new product.