Sea salt and table salt are both about 90% or more sodium chloride, and they contain identical amounts of sodium by weight: 40%. The real differences come down to how they’re made, what else is in them, and how they behave in your cooking. Neither one is meaningfully healthier than the other.
How Each Salt Is Made
Table salt is mined from underground deposits left behind by ancient seas. After extraction, it goes through heavy processing to strip away other minerals, leaving behind pure sodium chloride crystals. Anti-caking agents are added to keep it flowing freely from the shaker, and in most countries, iodine is added as a public health measure to prevent thyroid problems.
Sea salt takes a simpler path. Seawater or water from saltwater lakes is collected and left to evaporate, either in open-air ponds under the sun or in controlled facilities. Because the processing is minimal, sea salt retains small amounts of other minerals like calcium, potassium, and magnesium. These trace minerals give different sea salts their subtle color and flavor variations, but they’re present in such tiny quantities that they don’t contribute meaningfully to your daily nutrient intake.
Sodium Content Is the Same
This is the most common misconception. Many people switch to sea salt believing it’s lower in sodium, but gram for gram, the sodium content is identical. Both contain 40% sodium by weight. A teaspoon of either adds roughly the same amount of sodium to your food.
There is one practical twist, though. Because sea salt crystals are often larger and coarser than fine table salt, a teaspoon of sea salt may actually contain slightly less salt by weight, since the bigger crystals don’t pack together as tightly. That can make it seem “lighter” in sodium, but it’s just a matter of crystal size, not chemistry. If you measured both by weight instead of volume, the sodium would be the same. The current dietary guideline for adults is to stay under 2,300 milligrams of sodium per day, and that limit applies regardless of which salt you use.
Why They Taste Different
If you’ve ever sprinkled flaky sea salt on a dish and thought it tasted “saltier” or more complex than table salt, you weren’t imagining it. The shape and texture of salt crystals directly affect how your tongue perceives saltiness.
Salt crystals with more surface area dissolve faster on the tongue, which creates a quicker, more intense burst of flavor. Research on crystal shape found that irregular, flaky, or pyramidal crystals (the kind typical of sea salt and finishing salts) dissolved up to 3.8 times faster than compact cubic crystals. That translated into up to 17% higher peak saltiness, and the sensation hit up to 40% sooner. Sea salt crystals are naturally porous, rough-surfaced aggregates of smaller crystals stuck together. When they hit saliva, they break apart quickly, flooding your taste buds with salt all at once.
Table salt, by contrast, is refined into uniform, dense cubes. These dissolve more slowly and steadily. The result is a more even, less punchy salt flavor. This is why chefs often use coarse sea salt or flaky salt as a finishing touch on dishes, where you want that hit of salinity right when you bite in, while using table salt for baking and cooking where it dissolves into the food anyway.
Iodine: A Practical Difference
One genuinely important distinction is iodine. Table salt has been fortified with iodine since the 1920s, and for many people it remains a primary dietary source of this essential nutrient. Your thyroid needs iodine to produce hormones that regulate metabolism and support brain development.
Most sea salts are not iodized. If you’ve fully replaced table salt with sea salt in your kitchen, you may be getting less iodine than you think. This isn’t necessarily a problem if you eat seafood, dairy, or eggs regularly, since those are also good iodine sources. But it’s worth being aware of, especially if your diet is otherwise limited in iodine-rich foods.
The Microplastics Question
Because sea salt comes directly from ocean water, it carries whatever contaminants are in that water, including microplastics. Studies consistently find higher microplastic counts in sea salt compared to rock salt or lake salt, which makes sense given the level of plastic pollution in coastal waters.
The numbers vary dramatically by region. Sea salt samples from China contained 550 to 680 particles per kilogram, while samples from Croatia reached as high as 20,000 particles per kilogram. Rock salt (the source of table salt) generally tested lower: 7 to 367 particles per kilogram depending on the country. U.S. sea salt samples ranged from 50 to 800 particles per kilogram.
To put this in context, you consume about 3 to 6 grams of salt per day, so the actual number of microplastic particles you’d ingest from salt alone is quite small compared to what you take in from water, air, and food packaging. Still, if minimizing microplastic exposure matters to you, rock-derived table salt is the lower-exposure option.
Which One Should You Use
For everyday cooking where salt dissolves into the food, table salt works perfectly well. It’s consistent, inexpensive, and provides iodine. Its fine crystals also measure more predictably in recipes, which matters in baking.
Sea salt, flake salt, and other coarse varieties shine as finishing salts. Their irregular crystals deliver a stronger initial burst of flavor, so you can often use less of them to get the same perceived saltiness. The trace minerals and varied textures also add subtle complexity that a uniform table salt can’t replicate. Sprinkling a pinch of flaky sea salt over roasted vegetables, chocolate, or a steak right before serving is where it earns its higher price tag.
From a health standpoint, the choice is essentially neutral. Your body processes the sodium the same way regardless of the source. The differences that matter are culinary: crystal size, texture, dissolving speed, and whether you want that satisfying crunch of a coarse grain on top of your food.