People use selenium for weight loss because this mineral is important for maintaining healthy thyroid function.
The thyroid gland plays a critical role in energy metabolism and body weight regulation. If your diet is deficient in selenium, it could impair normal thyroid function and increase risk factors for developing obesity,
Selenium is the chemical base of enzymes used to deiodinate T4 (thyroxine) in T3 (triiodothyronine). This is necessary to convert basically inactive T4 into active T3.
If the body does not have enough selenium, T4 may not be adequately converted, and T3 levels may decline as a result. This can lead to various symptoms of sluggish thyroid function; a condition called hypothyroidism.
Some of the most common of these symptoms include depression, brain fog, fatigue, hair loss, easy weight gain, and resistance to losing weight. [1]



- Cofactor for antioxidant enzymes
- Supports thyroid function & metabolism
- Promotes immune function & fertility
Selenium Effects in the Body
Selenium is a trace mineral found naturally in the human diet in foods such as brazil nuts, leafy greens, healthy meats and whole wheat grains.
It acts as an antioxidant helping to protect against oxidative damage. This essential mineral is also incorporated into selenoproteins that have a wide range of functions in the body.
People use selenium supplements for weight loss, and a lot more. According to the Natural Medicines Comprehensive Database (NMCD), this supplement is also used for the following:
- Dyslipidemia, atherosclerosis, hypertension and cardiovascular disease;
- Cognitive decline with aging;
- Alcohol-related liver disease;
- Hepatitis C and HIV/AIDS;
- Various types of cancer;
- Eczema and psoriasis;
Selenium is also used for osteoarthritis, rheumatoid arthritis (RA), chronic fatigue syndrome (CFS) and stroke. There are other various uses as well. [2]
A deficiency in this mineral could interfere with normal thyroid function and cause you to put on weight faster or to have difficulty reducing your body fat percentage.
However, if you are not deficient in selenium, it is unlikely that taking more through supplements or dietary changes will cause you to lose weight. There are other supplements that may be more effective for this use.
Iodine and Selenium for Weight Loss
The trace minerals selenium and iodine are both important for healthy weight management by facilitating normal thyroid function.
Without sufficient selenium, your body cannot convert the thyroid hormone T4 into its active form known as T3. Without sufficient iodine, your body cannot make adequate amounts of T4 or T3.
T3 and T4 thyroid hormones are required in proper amounts for healthy metabolism. These two hormones are involved in nearly every physiological process in the body by helping you convert stored energy into fuel within your cells.
The thyroid gland is often called the body’s “Master” gland. It works with the pituitary gland and the hypothalamus to regulate metabolism in all cells throughout the body.
The tissues of the thyroid gland are the only in the body that can absorb iodine. The thyroid gland’s primary function is to trap iodine from the blood, and then use it to produce T4, and to a lesser degree, T3.
This process involves attaching either 3 or 4 atoms of iodine to a molecule of the amino acid tyrosine. Stated differently, a backbone of tyrosine supports 3 atoms of iodine in T3, and 4 atoms of iodine in T4.
T4 is considered to be the inactive form of the hormone. To be made active, it must get converted with the help of the deiodinase enzymes that contains selenium.
According to Wikipedia, “Selenium in iodotyrosine deiodinase, as selenocysteine, plays a crucial role in determining the free circulating levels of T3. Selenium deficiency can have implications in fall of T3 levels.”
According to EndocrineWeb.com, a healthy thyroid gland contains more per-gram selenium than any other type of tissue. [3]
If you do not get enough iodine and selenium in your diet, or by taking a supplement, then it becomes difficult for your thyroid gland to function properly.
If iodine and/or selenium levels remain too low for too long, more serious symptoms and conditions can develop – including Graves’ disease, autoimmune thyroiditis and Hashimoto’s thyroiditis. [1]
How Much Selenium Should I Take For Weight Loss?
If you think you may have low levels of this mineral that are contributing to thyroid dysfunction, then supplementing your diet with selenium may support weight loss.
While iodine deficiency is believed to be very prominent today, selenium deficiency is quite rare. It is more likely for a person to develop selenium toxicity (selenosis) than selenium deficiency. [1]
For most people, adequate selenium intake can be achieved easily via the diet. Some of the best food sources include organ meats, garlic, onions, molasses, kelp and shiitake mushrooms.
Of particular note are Brazil nuts. Unless grown in a selenium-poor environment, a single ounce of Brazil nut contains about 540 micrograms (mcg) of this trace mineral.
For adults who are not pregnant or breastfeeding, the US RDA (Recommended Daily Allowance) for selenium is 55 mcg. That means that eating just one or two Brazil nuts can satisfy the recommended daily intake. NIH warns that overconsumption of Brazil nuts can lead to selenium toxicity. [1]
Even though selenium deficiency is rare in most developed countries, many people still like to use a supplement to ensure adequate intake.
Processed foods, herbicides, pesticides, pharmaceuticals and epidemic health problems all cause minerals like iodine and selenium to be poorly absorbed by the body’s cells.
Getting Too Much Selenium
The NMCD states that there are more than 5000 dietary supplements available that contain selenium. 100 mcg and 200 mcg pills allow users to ensure that they are selenium-sufficient without putting them at risk for selenosis.
According to NIH’s Office of Dietary Supplements, the upper tolerable daily limit (UL) for selenium is 400 mcg. [1] It is generally recommended to begin taking a selenium supplement whenever you begin taking an iodine supplement.
Since these two minerals works together to support thyroid function, you want to make sure your intake of selenium is sufficient to support thyroid function given your iodine consumption.
If you follow the 400 mcg/day UL for this mineral, you should not experience adverse effects or develop signs of toxicity. However, always be mindful for the development of any of the following selenosis symptoms:
- Nervous system abnormalities;
- Breath that smells like garlic;
- Skin lesions and/or rashes;
- Fatigue and/or irritability;
- Spotted (mottled) teeth;
- Brittle hair and/or nails;
- Metallic taste in mouth;
- Hair and/or nail loss;
- Diarrhea;
- Nausea;
More serious symptoms of consuming too much selenium are also possible. Consuming very high amounts over long periods of time, can lead to severe gastrointestinal and neurological symptoms, breathing problems, cardiovascular problems, hair loss, muscle tenderness, hand tremors, dizziness, facial flushing, and kidney problems. [4]
Talk with your doctor about the benefits and side effects of using iodine and selenium for weight loss or any other purpose.
Maintaining a proper balance of these and other minerals is important for health on numerous levels. Be sure to tell your doctor about any health conditions you have, and about any medications or supplements you use.
- Natural Medicines - Selenium
- Sunde RA. Selenium. In: Bowman B, Russell R, eds. Present Knowledge in Nutrition. 9th ed. Washington, DC: International Life Sciences Institute; 2006:480-97
Article last updated on: July 8th, 2018 by Nootriment