Amount of Evidence: Low Potential Benefits: Reasonable Safety: High
TABLE OF CONTENTS
What is fucoxanthin?
Fucoxanthin is a carotenoid found primarily in brown seaweed. It is primarily being used for fat loss but has been shown to be beneficial in other areas as well. In this article, we will look at the main benefits of fucoxanthin, its potential side effects, and how to use it the right way.
Potential benefits
It is important to note that all of the potential benefits mentioned below are dose-dependent. In general, the higher the dose you take, the more pronounced the effects will be. However, they do reach a plateau at a certain point. We will discuss the best dosing protocol later in this article.
Major benefits
Weight loss – Fucoxanthin notably increases metabolic rate. This effect has been noted primarily in obese, premenopausal women but likely applies to other groups of people as well. It appears to be the case that the more overweight a person is, the more effective fucoxanthin tends to be for weight loss. Some estimates say fucoxanthin could increase metabolic rate by as much as 450 kcal/day. It is important to note that this effect is not acute and happens over a longer period of time. It typically takes 5-10 weeks to start noticing this benefit.
Reduced liver fat – While more research is needed to show how reliable this effect is, fucoxanthin seems to significantly reduce liver fat.
Minor benefits
Lowered blood pressure – This effect is caused indirectly. Fucoxanthin by itself does not seem to influence blood pressure but the fact that it aids weight loss and fat loss means it can lower blood pressure in obese or overweight individuals.
Reduced inflammation – The supplement has been shown to decrease CRP (C-reactive protein) and may also be able to influence other markers of inflammation. This effect may also be indirect and caused by weight loss.
Lowered triglycerides – While the effect is not too significant, fucoxanthin can lower circulating triglycerides.
Unproven benefits
The effect of fucoxanthin on these parameters has either not been adequately researched, or the science shows little to no efficacy in these areas.
Skin quality – Unfortunately, fucoxanthin doesn’t seem to help with acne, wrinkles, or other skin problems. It also doesn’t seem to help hydrate the skin or keep it elastic.
Blood flow – No significant change has ever been observed.
DNA protection – Fucoxanthin supplements have not been shown in human studies to protect DNA from oxidative damage. However, studies on rats show that the carotenoid may be slightly protective against UV(B) radiation damage.
Brain health and cognition – Improving brain health and cognition is not a direct effect of the supplement.
Testosterone – The supplement does not significantly affect DHT, free testosterone, or total testosterone levels.
Cholesterol – The supplement may affect HDL and LDL cholesterol levels but we do not know enough about the connection yet.
Cancer – The supplement does not seem to affect cancer rates or tumor growth, at least it has never been shown by reliable human studies.
Thyroid hormones – There is no significant interaction between the supplement and serum T3 and T4.
Well-being – Fucoxanthin supplementation doesn’t appear to increase subjective well-being.
Strength and muscle growth – The supplement does not help you gain strength or muscle mass faster, at least this effect has never been shown by scientific studies.
Asthma – The supplement has not been shown to help with asthma to a significant degree.
Power output – Fucoxanthin has not been shown to directly influence power output during cardio or resistance training. It does not impact VO2 max or aerobic endurance either.
Kidney function – Biomarkers of kidney function are not significantly altered by taking fucoxanthin.
Sleep quality – The supplement does not appear to directly improve sleep quality. It also doesn’t directly affect sleep duration.
Stress and anxiety – Fucoxanthin supplements have no direct effect on cortisol levels. However, they may indirectly lower stress and anxiety levels if you are deficient in this nutrient.
Possible side effects
These side effects are dose-dependent and the risk for them increases (most often linearly but sometimes exponentially) as the dose is increased. Some of the side effects only apply to very high doses.
Diarrhea – Diarrhea caused by this supplement is not dangerous (assuming it doesn’t lead to severe dehydration) and usually only occurs if you take very high doses at once.
Nausea – Just like diarrhea, this side effect is not dangerous but can be unpleasant.
Fucoxanthin toxicity – While toxicity is rare and may not even be a thing, taking high amounts of fucoxanthin on regular basis could possibly lead to some health problems. To stay on the safe side, it’s best to avoid very high doses since we don’t yet know for sure whether or not they are safe to take over a long period. Specifically, you want to stay below 20 mg a day.
Who should not take fucoxanthin?
You should probably avoid taking the supplement if you:
consume a lot of seaweed
experience a severe adverse reaction after taking the supplement
aren’t obese or overweight (since weight loss is the main benefit of the supplement)
are on a tight supplement budget (since there are more cost-effective supplements on the market)
Who will benefit the most?
You should consider taking the supplement if you:
are overweight and wish to lose weight
have high amounts of liver fat
have a high budget for supplements (since the supplement appears to be safe in most cases and rarely does more harm than good)
How much fucoxanthin should you take?
The optimal dose of fucoxanthin appears to be somewhere between 3-8 mg. Higher doses may be more effective for fat loss and other effects but they have not been used in many human studies.
Taking more than 8 daily is probably unnecessary. Also, the higher the dose you take, the higher the risk for certain side effects.
Food sources of fucoxanthin
The richest food sources of this carotenoid are seaweed and microalgae.
Specifically, species that contain most of this carotenoid are Odontella aurita, Phaeodactylum tricornutum, Isochrysis, Dictyota coriacea, Myagropsis myagroides, and Fucus vesiculosus. These typically contain 6-20 mg per gram.
Best time to take fucoxanthin
Since fucoxanthin is fat-soluble, you need to take it along with a source of dietary fat to absorb it properly.
Whether you take the supplement in the morning or the evening doesn’t matter. It does not interrupt your sleep in any way.
Where to buy fucoxanthin
Amazon seems to be the best option for ordering fucoxanthin supplements in most countries. They offer some very affordable products that are backed by many positive reviews. Also, you can choose from a wide range of brands there without having to spend time searching through other markets on the internet.
One thing you should pay attention to is that some brands display the dosage per serving and not per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.
FAQ
The supplement can be taken daily and does not need to be cycled. However, it is not a problem at all if you don’t take it every day. Cycling the supplement could lead to better absorption but it has never been proven.
Yes. The nutrient doesn’t impact your sleep in any negative way in the short term.
The supplements rarely go bad but they can lose potency over time.
Keep the supplements in a cold, dark, and dry place and they will remain just as potent for many years.
While we don’t yet know if there is a toxic dose, too much fucoxanthin in the system can possibly cause some health problems. To prevent these side effects, it is best to stay below 20 mg a day.
The half-life of fucoxanthin is around 7 hours. The nutrient stays in your system for about 3 days.
In the long-term, it typically takes around 5-16 weeks after you start taking the supplement to start noticing the weight loss benefits.
Yes, most fucoxanthin supplements on the market are vegan-friendly.
The nutrient is fat-soluble, just like other carotenoids.
No, it doesn’t. The supplement does not interfere with fasting in any significant way. However, it is still better to take it with a meal to increase its absorption.
References
Most of the information provided in this guide is based on scientific research that can be found and verified in the PubMed medical library. We excluded from consideration studies that are either confounded or have a high conflict of interest.
Anecdotal evidence (from reports on Reddit, YouTube, and other sources) is also taken into account unless it contradicts scientific research.
