Maris Sal: properties, uses, pros, cons, safety

Maris Sal is the INCI name for sea salt, defined in cosmetics as a group of naturally occurring substances consisting of inorganic salts derived from seawater.

It should not be regarded simply as a synonym for Sodium Chloride: sodium chloride is normally the predominant component of ordinary sea salt, but Maris Sal is a natural mineral mixture that may also contain magnesium, potassium, calcium salts, sulfates, bromides, and other minerals in variable proportions.

The documented cosmetic function of Maris Sal is SKIN CONDITIONING, meaning that it helps maintain the skin in good condition.

No specific Cosmetics Regulation provisions are identified for the ingredient under Annexes II–VI of the EU Cosmetics Regulation.

Description

Maris Sal is obtained from seawater through concentration and evaporation of the water, followed by crystallization of the salts.

Its composition depends strongly on geographical origin and manufacturing process.

Ordinary sea salt contains mainly sodium chloride, accompanied by smaller and variable quantities of:

• magnesium chloride;

• magnesium sulfate;

• potassium chloride;

• potassium sulfate;

• calcium salts;

• bromides;

• bicarbonates;

• other trace elements and minerals.

The amounts of minor constituents may vary considerably according to:

• sea or basin of origin;

• salinity of the water;

• climatic conditions;

• evaporation process;

• crystal fractionation;

• washing;

• refining;

• drying.

Maris Sal and Dead Sea Salt

Maris Sal does not necessarily mean Dead Sea Salt.

Dead Sea salt may be labeled as Maris Sal when used as a cosmetic ingredient, but its mineral composition is very different from that of ordinary ocean sea salt.

Dead Sea Salt is generally much richer in:

• magnesium salts;

• potassium salts;

• bromides;

and may contain a much lower proportion of sodium chloride than ordinary sea salt.

This distinction is important because formulation behavior and effects on the skin may depend on the actual mineral composition, not simply on the INCI name.

Manufacturing process

Sea salt production may include:

• intake of seawater;

• sedimentation;

• preliminary filtration;

• concentration of the water;

• solar or thermal evaporation;

• crystallization of the salts;

• harvesting;

• drainage of residual brine;

• washing;

• drying;

• optional grinding;

• sieving;

• purification;

• control of mineral composition;

• packaging.

In traditional processes, evaporation may occur mainly through solar energy and wind in salt ponds.

For more controlled cosmetic grades, additional operations may include:

• refining;

• recrystallization;

• removal of insoluble matter;

• particle-size control;

• reduction of contaminants;

• standardization of mineral content.

The degree of refining partly determines the presence of trace minerals: a highly purified product may approach the composition of sodium chloride more closely, while a less refined salt retains a more complex mineral fraction.

Main compounds present

Depending on its origin, Maris Sal may contain mainly:

• sodium chloride;

• magnesium chloride;

• magnesium sulfate;

• potassium chloride;

• potassium sulfate;

• calcium chloride;

• calcium sulfate;

• bromide salts;

• bicarbonates;

• traces of other mineral salts.

In ordinary sea salt, sodium chloride is normally predominant.

This cannot be generalized to salts from basins with unusual mineral compositions. Dead Sea salt, for example, may contain high proportions of magnesium chloride and potassium chloride.

It is therefore not appropriate to assign a universal percentage composition to Maris Sal.

Identification data and specifications

Indicative physicochemical properties

Cosmetics

Maris Sal may be used in:

• bath salts;

• bath products;

• scrubs;

• body cleansers;

• facial cleansers;

• shampoos;

• scalp products;

• masks;

• creams;

• lotions;

• foot-care products;

• spa products;

• formulations inspired by balneotherapy.

Its documented cosmetic function is SKIN CONDITIONING.

Skin conditioning

At appropriate concentrations, the mineral fraction may contribute to skin feel and to the overall sensory characteristics of the formulation.

Particular interest concerns salts rich in magnesium.

Studies performed with magnesium-rich Dead Sea salt solutions have shown, under specific experimental conditions, improvements in:

• stratum corneum hydration;

• barrier function;

• skin roughness;

• redness.

These findings, however, relate to specific Dead Sea mineral solutions and should not automatically be attributed to every ingredient labeled Maris Sal.

Exfoliating action

When used as crystals in scrubs, salt can provide mechanical exfoliation.

Its intensity depends mainly on:

• crystal size and shape;

• concentration;

• vehicle;

• pressure applied;

• duration of massage.

This physical property should not be confused with the officially documented cosmetic function of Maris Sal, which remains Skin Conditioning.

Effect on formulation

As an electrolyte, Maris Sal can significantly influence the physical properties of a cosmetic product.

In particular, it may:

• increase or decrease the viscosity of surfactant systems;

• modify gel structure;

• influence emulsion stability;

• modify water activity;

• affect skin feel;

• alter the solubility of other ingredients.

In cleansers containing certain surfactants, small additions of salts can substantially increase viscosity; beyond a certain level, however, viscosity may decrease again or the system may become unstable.

The concentration should therefore be optimized for the specific formulation.

Pros

• It is a mineral ingredient of natural origin.

• Its documented cosmetic function is Skin Conditioning.

• It is readily soluble in the aqueous phase.

• It can be used in bath products, cleansers, and body treatments.

• It can provide physical exfoliation when formulated as crystals.

• It can be used to modify the viscosity of certain cleansing systems.

• Magnesium-rich marine salts have shown interesting effects on skin barrier function in specific studies.

• It has no specific restriction under Annexes II–VI of the EU Cosmetics Regulation.

• It is chemically stable when kept dry.

• It can be produced by solar evaporation using relatively simple processes.

Cons

• The INCI name does not specify the mineral composition.

• An ocean-derived Maris Sal and Dead Sea salt may be chemically very different.

• High concentrations may cause stinging or burning on damaged skin.

• Frequent use at high concentrations may be drying for some individuals.

• Coarse crystals used aggressively may irritate sensitive skin.

• It may reduce tolerability on already irritated or cracked skin.

• Electrolytes can destabilize emulsions and gels.

• It can alter cleanser viscosity in a non-linear manner.

• Chlorides may promote corrosion of certain metals or packaging components.

• The presence of trace minerals does not automatically imply a clinically demonstrated “remineralizing” effect.

Safety and regulation

Maris Sal generally has a low allergenic potential. Adverse effects are more commonly irritative and depend on concentration and skin condition.

Irritation and damaged skin

Concentrated saline solutions may cause:

• stinging;

• temporary burning;

• tightness;

• irritation;

• dryness.

These effects may be more noticeable on:

• abrasions;

• cuts;

• freshly shaved skin;

• active dermatitis;

• severely cracked skin.

This does not mean that sea salt is intrinsically harsh: the effect depends on concentration, contact time, and the condition of the skin barrier.

Balneotherapy and dermatology

Saline solutions, especially those rich in Dead Sea minerals, have been used in dermatology in balneotherapy and balneophototherapy.

Clinical studies have evaluated such approaches in conditions including psoriasis and atopic skin.

These findings do not allow Maris Sal, as an ordinary cosmetic ingredient, to be automatically assigned a therapeutic function.

A cosmetic containing sea salt should not automatically be presented as a treatment for:

• psoriasis;

• atopic dermatitis;

• eczema;

• other skin diseases.

Microbiology

Highly concentrated salt solutions can reduce water activity and inhibit the growth of certain microorganisms.

However:

Maris Sal should not automatically be regarded as a cosmetic preservative.

At concentrations normally used in cosmetics, it may not provide adequate microbiological protection and should be incorporated into an appropriately validated preservation system where necessary.

EU Cosmetics Regulation provisions

No specific:

Cosmetics Regulation provision

is indicated for Maris Sal under Annexes II–VI of Regulation (EC) No 1223/2009.

The name MARIS SAL is included in the current EU glossary under entry 16018.

The absence of a specific provision does not replace the safety assessment of the finished product, particularly when high concentrations or salts with unusual mineral compositions are used.

Food use

Sea salt is also a common food ingredient, used mainly to:

• provide saltiness;

• preserve certain foods;

• control fermentation;

• modify texture and water activity.

From a nutritional standpoint, the main component of ordinary sea salt is generally sodium chloride.

The presence of small amounts of other minerals does not automatically make sea salt nutritionally superior to ordinary table salt.

It is also important to distinguish:

cosmetic-grade Maris Sal from food-grade sea salt.

A raw material that complies with cosmetic specifications should not automatically be considered suitable for food consumption without the corresponding food-grade documentation and compliance.

Raw-material control

For professional evaluation, it is advisable to obtain:

• an updated SDS;

• a Certificate of Analysis (COA);

• technical data sheet;

• geographical origin;

• production method;

• mineral composition;

• sodium chloride;

• magnesium;

• potassium;

• calcium;

• bromides where relevant;

• sulfates;

• moisture;

• insoluble matter;

• solution pH according to specification;

• metals;

• arsenic;

• lead;

• cadmium;

• mercury;

• other relevant environmental contaminants;

• microbiological specifications where relevant;

• purity;

• stability;

• storage conditions.

For Dead Sea Salt, it is particularly important to obtain an actual mineral analysis, because the name Maris Sal alone does not prove either Dead Sea origin or a particular magnesium concentration.

Environment

Maris Sal is derived from an extremely abundant natural mineral resource, but its environmental impact depends on the production method.

Relevant considerations include:

• seawater intake;

• land area occupied by salt ponds;

• management of coastal ecosystems;

• energy required for pumping and evaporation;

• drying;

• grinding;

• transport;

• management of residual brines.

Solar evaporation can reduce direct energy requirements compared with thermal processes.

Traditional salt ponds may also provide important habitats for many organisms, especially waterbirds, and should be managed without causing excessive disruption to local ecosystems.

Discharge of highly concentrated brines can, however, alter the salinity of aquatic environments and should be properly managed.

Conclusion

Maris Sal is the cosmetic name for natural sea salt, consisting of a mixture of inorganic salts derived from seawater.

Its documented cosmetic function is SKIN CONDITIONING.

Ordinary sea salt is generally composed predominantly of sodium chloride, but Maris Sal should not be regarded as chemically equivalent to Sodium Chloride alone, because it may contain variable proportions of magnesium, potassium, calcium salts, bromides, and other minerals.

Particular attention should be paid to the distinction between ordinary sea salt and Dead Sea Salt, since their mineral compositions may differ substantially.

No specific Cosmetics Regulation provisions are identified for the ingredient.

Maris Sal can be considered a generally favorable and low-risk cosmetic ingredient when used at appropriate concentrations, with particular attention to origin, mineral composition, purity, metals and contaminants, concentration in the formulation, possible irritation of compromised skin, formulation compatibility, and quality of the commercial grade.