Start with the ingredient list on the packaging. Sea salt is the base of our bath salts, but a product description is no substitute for the full INCI list. Check the label on the jar in your hands.
The product name helps you choose a scent: Relax pairs lavender with bergamot; Mojito pairs lime with mint. If you have sensitivities or allergies, check the full list, not just the ingredients highlighted on the front.
Sodium laureth sulfate is a foaming agent. Codes beginning with CI identify certain colourants. Where they appear on the label, they are part of the formula, alongside the salt and the aromatic ingredients.
For Baby SPA, also check the age stated on the label, the amount, the temperature and the time. Neither the name nor the absence of colourants on its own means that it suits every child. If anything in the instructions is unclear, ask before you use it.