Fucoxanthin is an antioxidant found in wakame, a type of brown kelp used in Asian cuisine.
Fucoxanthin burned fat in lab tests on rats and obese mice, prompting the rodents to lose weight, report Kazuo Miyashita, PhD, and colleagues.
Fucoxanthin is also available in dietary supplement form. Although it is found naturally in edible brown seaweed, there’s some evidence that fucoxanthin from food sources in poorly absorbed. For instance, a small study found that one week of wakame intake (providing 6.1 mg of fucoxanthin per day) did little to raise the body’s levels of fucoxanthinol.
Fucoxanthin is a brown seaweed pigment that is found in most brown seaweeds, as well as a few other marine sources. It is a xanthophyll, which is a molecule structurally similar to beta-carotene and vitamin A; yet fucoxanthin does not possess vitamin-like activity in the body.
Fucoxanthin, via its metabolites, seems to be stored in fat cells for a prolonged period of time and can induce fat loss while inhibiting fat cell differentiation and proliferation.
The compound targets abdominal fat, in particular, and may help reduce oversized guts, the scientists say. Their study was presented at the 232nd national meeting of the American Chemical Society.
Dr Miyashita’s team studied the effects of fucoxanthin on more than 200 rats and mice.
They found it fought flab on two fronts.
In obese animals, the compound appeared to stimulate a protein called UCP1 which causes fat to be broken down.
The pigment also caused the liver to produce a compound called docosahexaenoic acid (DHA), which can help cut levels of “bad” cholesterol associated with obesity and heart disease.
No adverse side effects were seen in the animals used in the study.
Fucoxanthin shows promise in the treatment and prevention of obesity, according to a research review published in Nutrition, Metabolism, and Cardiovascular Diseases in 2015. In their analysis of previously published experimental studies, the review’s authors found that fucoxanthin may fight obesity in a number of ways.
A few genes and their proteins are increased in the liver in response to an obesogenic diet, and the increase seen appears to be reduced by fucoxanthin in either a rehabilitative (taken after obesity) manner or when taken alongside a high fat diet.
Preliminary evidence suggest that fucoxanthin reduces triglycerides, reliability of this decrease not fully established
Only one clinical trial has been conducted on the possible weight-loss effects of fucoxanthin. This 16-week trial used Xanthigen®, a dietary supplement containing brown seaweed extract and pomegranate-seed oil . In one arm of this study, 110 obese (BMI >30) premenopausal women, 72 of whom had non-alcoholic fatty liver disease (NAFLD), received either a placebo or Xanthigen® three times a day before meals for a total daily dose of 2.4 mg fucoxanthin and 300 mg pomegranate-seed oil. Participants followed a controlled diet that limited total energy intake to 1,800 kcal/day. Compared to the placebo group, those receiving Xanthigen® lost significantly more body weight by the end of the trial (mean loss of 6.9 kg vs. 1.4 kg for placebo in participants with NAFLD; mean loss of 6.3 kg vs. 1.4 kg for placebo in those without NAFLD).
May Protect the Brain
In mice with traumatic brain injury, fucoxanthin reduced brain cell death .
May Have Anti-Diabetic Effects
In a study on mice on high-fat diets, fucoxanthin reduced insulin resistance, which is a large factor in diabetes .
May Protect Against Oxidative Stress
In cells, fucoxanthin increased glutathione, an antioxidant, after its depletion from UVB radiation .
An important component in wakame, fucoxanthin, has been shown to exert an anti-diabetic effect on animal study subjects. A 2009 study conducted in Japan examined the anti-obesity and anti-diabetic effects of fucoxanthin-rich wakame lipids on obese mice. When it was added to the high-fat diet, it significantly suppressed body weight.
Before the wakame treatment, the mice showed signs of hyperglycemia, hyperinsulinemia and hyperleptinemia, but adding this seaweed into the diet normalized these conditions. The researchers concluded that wakame has the ability to prevent diabetes, related disorders and obesity by reversing insulin resistance that is due to a high-fat diet. (3, 4)
Although fucoxanthin has no proven side effects in humans (possibly due to the limited number of human trials), in mice, it increased cholesterol levels. However, it didn’t have negative effects on the kidney, liver, spleen, and gonads or cause any cellular mutations in the mice [32, 33]. Fucoxanthin inhibits the enzyme CYP3A4. CYP3A4 is responsible for the metabolism approximately 45–60% of prescribed drugs [34, 35, 36, 37, 38].
- Opioids: sufentanil  and methadone 
- Immunosuppressants: cyclosporine , tacrolimus , and sirolimus 
- Antihypertensive drugs: felodipine  and nifedipine 
- Anticancer drugs: endoxifen , tamoxifen , and sunitinib 
- Sedatives: midazolam 
- Cholesterol-lowering drugs (statins): simvastatin , atorvastatin, and lovastatin 
- Antibiotics: erythromycin 
- Corticosteroids: fluticasone propionate 
Human studies imply a range of 2.4mg to 8mg per day of fucoxanthin extract will be effective.
You will probably find that the product label states the total seaweed weight with a percentage of fucoxanthin next to it and possibly in brackets, for example: 250mg Seaweed Extract (stand. 1% fucoxanthin).