A viral social media trend encouraging people to make their own sea salt by boiling seawater poses potential health risks and costs significantly more than buying salt in a store, according to a report by French television network TF1.
The online hack, which has been widely shared across social platforms as a completely natural and cheap alternative, involves gathering seawater and heating it until the liquid evaporates. However, a biophysicist cited in the report warned that consuming the resulting salt could be dangerous because untreated seawater often contains toxic environmental contaminants.
The biophysicist explained that sea salt extracted through rapid home boiling is susceptible to retaining residues of pesticides, pharmaceutical drugs, hydrocarbons, and heavy metals. Unlike regulated food production, boiling coastal water on a kitchen stove concentrates dissolved chemical pollutants alongside the salt crystals.
Health Hazards of Boiling Seawater
In addition to health risks, the report highlighted that the home method is financially impractical. Seawater contains roughly 35 grams of salt per liter, requiring large amounts of gas or electricity to evaporate the liquid. As a result, producing homemade sea salt costs five to ten times more than purchasing standard table salt at a supermarket.
The report was produced by the TF1info video news desk and aired as a fact-check segment titled Faites-le vous-meme during the weekend edition of TF1's 8pm news broadcast on August 22, 2026. TF1 is France's largest private television network, and its evening news bulletin regularly investigates consumer trends and viral internet claims.
Commercial Production and Coastal Runoff
Commercial sea salt is typically manufactured in coastal salt marshes using solar evaporation, where seawater moves through a series of shallow settling basins over several months. Sun and wind gradually evaporate the water, allowing unwanted minerals and sediments to precipitate out before the remaining sodium chloride is harvested and purified for consumer use.
By contrast, water collected near public beaches or coastal shores frequently absorbs agricultural runoff, sewage discharge, and fuel residue from maritime shipping. Because household boiling cannot filter out these dissolved chemical compounds, health experts advise against consuming DIY sea salt made from shoreline ocean water.
