March 22, 2017



Natural Standard Monograph, Copyright © 2013 (www.naturalstandard.com). Commercial distribution prohibited. This monograph is intended for informational purposes only, and should not be interpreted as specific medical advice. You should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Related Terms

  • Balneotherapy, hydrotherapy, seawater, thalassotherapy.


  • Thalassotherapy, or seawater therapy as it is sometimes known, is the use of seawater and seaweed for a variety of cosmetic and medicinal purposes, from reducing the appearance of cellulite to relieving joint pain. The benefits of thalassotherapy supposedly reside in the minerals dissolved in sea water, including magnesium, calcium, sodium, iodine, silicon, zinc, selenium, sulfur, and fluoride. Advocates claim these minerals enter the body through pores on the skin and draw out toxins.

  • Thalassotherapy is a health and beauty treatment developed in France around 1969. The name of this therapy is derived from "thalassos," the Greek word for sea. It is sometimes classified as a form of hydrotherapy, a term that describes the use of water from any source to treat a medical condition.

  • Thalassotherapy is most commonly practiced at spas in countries surrounding the Mediterranean and Dead seas, which are thought to contain unusually large amounts of minerals.

  • Proponents claim that thalassotherapy offers many cosmetic and medical benefits. For instance, exposing the body to seawater supposedly reduces cellulite and encourages the body to lose weight. Advocates claim that this modality assists in the relief of back pains, increases circulation throughout the body and may treat hypertension, arteriosclerosis, asthma, bronchitis, muscle atrophy, and scabies.

  • Use of whirlpools, heated water and jet streams of water is thought to relax a patient, thus improving their quality of life for the duration of the treatment.


  • The seawater used in thalassotherapy is usually warmed by the spa or health center before application on the body.

  • Underwater jets are sometimes used to target specific areas of the body, such as the back and neck. These jets expel water out of a special tube at a very high pressure. The result is a feeling of the water from the jet pushing into the skin. Distance spraying of seawater may target specific areas of the body, such as the buttocks or thighs. In this form of thalassotherapy, the patron stands on dry land as water is sprayed at them from a high-pressure jet, and some claim that it reduces the appearance of cellulite. Some centers create waterfalls in pools to achieve the same purpose. All of these types of thalassotherapy are designed to supposedly encourage circulation, provide a gentle massage of muscles and damaged ligaments, as well as increase the body's absorption of minerals in the water.

  • Some centers also offer pools of alternating hot and cold water, which is thought to increase the body's circulation.

  • Patients usually wear a bathing suit for treatments, although some centers allow treatments to occur without any clothing on.

  • Some treatment pools, such as those with massage jets, are intended for only one person at a time. However, other treatments, such as sitting in whirlpools, may occur in the presence of other patrons.

  • In some cases, a thalassotherapist may coordinate the delivery of an underwater jet stream, water temperature and other aspects of treatment with seawater. In other cases, patrons simply choose a treatment, which is performed by machines. The most accessible form of thalassotherapy involves sitting in a spa communal pool.

  • There is currently no certification process for thalassotherapists in the United States.


  • Water from the Mediterranean and Dead seas is high in salt and magnesium. Advocates claim that exposure to high concentrations of these minerals invigorates the body, increases circulation and encourages weight loss.

  • A 2005 article by Merati et al. examined the physiological parameters of dipping patients into hot water with varying salt concentrations. The researchers found that patients dipped into hot salt water experienced an increased heart rate, but without vascular contraction.

  • A 2003 article by Tsuchiya et al. measured changes in blood lactate and pyruvate concentrations when healthy young men were dipped into seawater. Patients showed no change in blood lactate and pyruvate concentrations immediately after or 60 minutes after bathing.


  • Individuals who are allergic to algae should consult a qualified healthcare practitioner before receiving thalassotherapy.

  • There is a lack of systematic safety information on the various hydrotherapy techniques.

  • Sudden or prolonged exposure to extreme temperatures in baths, wraps, saunas, or other forms of hydrotherapy should be avoided, particularly in patients with heart disease, lung disease or during pregnancy. Warm temperature therapies can cause dehydration or low blood sodium levels, and adequate hydration and electrolyte intake should be maintained. Cold temperatures may worsen symptoms in patients with Raynaud's disease, chilblains, acrocyanosis, or erythrocyanosis.

  • The temperature of water should always be carefully monitored, particularly when treating patients with impaired temperature sensitivity, such as neuropathy. High temperatures or hydrotherapy involving electrical currents should be avoided in patients with implanted medical devices such as pacemakers, defibrillators or hepatic (liver) infusion pumps.

  • Skin irritation (dermatitis) may be caused by contact with contaminants or additives in water (such as essential oils or chlorine). Skin infections may occur if water is not sanitary, particularly in patients with open wounds. There are several reported cases of dermatitis and bacterial skin infections (such as with Pseudomonas aeruginosa or Staphylococcus aureus) associated with hot tub or whirlpool use.

  • Vigorous use of water jets should be avoided in patients with fractures, known blood clots, bleeding disorders, severe osteoporosis, open wounds, or during pregnancy.

  • Hydrotherapy should not delay the time to diagnosis or to use treatment with more proven techniques or therapies, and should not be used as the sole approach to treat illnesses. Patients with known illnesses should consult their physician(s) before starting hydrotherapy.

Author Information

  • This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).


Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

  1. Boulet LP. Algae-induced occupational asthma in a thalassotherapist. Occup Med (Lond). 2006 Jun;56(4):282-3. View Abstract

  2. International Medicinal Spa Association. www.medicalspaassociation.org

  3. Merati J, Solimene U, Cherina A, et al. Thalassotherapy effect on cardiovascular system and cardiac rhythm variability. Vopr Kurortol Fizioter Lech Fiz Kult. 2005 Jan-Feb;(1):13-6.View Abstract

  4. National Heart Blood and Lung Institute. www.nhlbi.nih.gov

  5. Tsuchiya Y, Shimizu T, Tazawa T, et al. Changes in plasma lactate and pyruvate concentrations after taking a bath in hot deep seawater. Tohoku J Exp Med. 2003 Dec;201(4):201-11.View Abstract

  6. World Health Organization. www.who.int/en

Copyright © 2013 Natural Standard (www.naturalstandard.com)

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.


March 22, 2017