Does Quercetin Help With Weight Loss?

There’s no better feeling then seeing your body change shape. The tone on the back of your arms is developing and you can just about see a sneak of those top two abs poking through. You’re progressing well and you know it.

But what you also know is that eventually your progress will start to slow and you’ll need to start thinking about that little kick start to get going again – a good fat burning supplement.

You’ve started researching nutrients that might help… and you’ve come across a plant chemical called quercetin.

Can it help you lose weight and drop fat? Is it the key to a better physique?

In this article we take a look. Here’s what we’ll cover:

• What is quercetin?
• Does it improve your health and performance?
• Does quercetin boost weight loss?

What is Quercetin?

Quercetin is a bioflavonoid – a type of chemical compound found in vascular plants.

It is one of the most abundant chemicals in fruit and vegetables, providing a source of pigmentation and giving each food its distinct color – that’s why you find it in a range of dark, vibrant-colored foods.

You’ll find it in apples, onions, red wine, dark cherries and dark green vegetables among other foods.

A number of dietary supplements also contain this flavonoid nutrient. These include various herbal remedies and over-the-counter health boosters, although typically it forms part of a blend with other nutrients rather than just on its own.

Does Quercetin Provide Any Health Benefits

Quercetin is said to have anti-inflammatory benefits as well as anti-oxidant, anti-carcinogenic and anti-artherogenic properties too.

This means it may boost a number of inflammatory-related health conditions, such as:

• Allergies
• Heart disease
• Infections
• High cholesterol
• Autoimmune symptoms

Quercetin has the ability to suppress pro-inflammatory pathways and down-regulate the enzymes and hormones responsible for the inflammatory response [1].

It has also been said to have potent anti-ageing effects on cells (in both humans and animals). But the science doesn’t necessarily back all of these claims up, with just as many studies showing limited benefits as the ones that do.

And most of these positives have been seen in cell cultured, petri-dish studies as opposed to in human participants.

It has a low bioavailability

The bioavailablity of quercetin is highly variable, with different people reporting different bioavailability when given the same does of the nutrient. This means that when ingested, only a certain amount will be absorbed and used; the rest is just eliminated from the body.

Food-derived quercetin for example has been found to have a low bioavailability of 52% plus or minus 15% [2].

Most benefits are seen in petri-dishes, not humans

Not only that though, the common consensus is that quercetin take-up in human tissue is quite low in general. So what you see in a petri dish (in vitro) and in humans (in vivo) can be completely different

It’s also got a low half-life, meaning it clears out of tissue quickly as well – so even the nutrients that are absorbed don’t have long within your cells to do what they’re reported to do.

What About Endurance Performance Benefits?

Quercetin is often added to supplements that promise to enhance your sports endurance performance.

But does it really?

In 2011, a systematic review and meta-analysis was published in Medicine and Science in Sports and Exercise [3]. This is about as solid as a scientific study gets and involves a statistical analysis of all independent research papers, pulled together into one big, mega study.

Based at the School of Applied Physiology in Georgia, the study found that whilst there were some significant benefits to quercetin supplementation on endurance performance, any benefits were in fact “trivial and small”.

That means that although it had a ‘statistical’ significance, this won’t translate to much of an actual benefit in the real world of sport.

This paper is often cited as the main reason why pharmaceutical companies add quercetin to their athlete performance supplements – and with such weak evidence behind the nutrient, it probably tells you about the standard of their products.

Key Point: Quercetin may improve health and have a small effect on performance, although the results of studies don’t seem to be unanimous.

Can Quercetin Help You Lose Weight?

Not if the research is anything to go by.

Study #1: Egert et al.

A pilot study (basically one of the first to research the nutrient directly for weight loss) found that there was “no evidence of an increase in metabolic rate or thermic effect with quercetin” [4].

In the study, a small group of 6 healthy women (pilot studies typically use small samples of participants) were given 150 mg of quercetin and then had their metabolism monitored for 3-hours using a specific indirect caliometry device.

At no point during the testing, or for the following 24-hour period, did metabolism change. Nor did measurements of heart rate or blood pressure either.

The Result: Quercetin made no difference to fat burning in a group of healthy women.

Study #2: Edwards et al.

This study monitored the effects of quercetin a much longer research period of 28-days [5].

A group of 22 men and women with high blood pressure were given either 730 mg of the nutrient or a placebo in a randomized, double-blind study. The supplement was split into two even doses.

Although blood pressure and mean arterial pressure decreased over the month, lipid biomarkers of fat burning and body weight didn’t change at all. 

The Result: Quercetin decreased blood pressure but had no effect on weight loss.

Study 3: Egert et al.

Published in the Journal of Nutrition [6], this study looked at the effects of quercetin on blood pressure, fat mass, body weight and waist circumference among other metabolic markers.

93 overweight participants were split into two groups. Half were given either 150 mg of the nutrient for 6-weeks and the other half given a placebo. They were then given a 5-week break before swapping over – what’s called a crossover trial approach.

After both trial periods, the results between groups and treatments were evaluated. Blood pressure had decreased by 3.4 mm.Hg in the quercetin group, whereas there was no change in the control.

However, there was no significant difference between groups for either body weight, waist circumference, fat mass or fat-free mass.

The Result: Quercetin had no effect on body composition.

Key Point: Quercetin may help to control blood pressure but has no effect at all on weight loss, body fat or any other marker of fat burning or body composition.

Summary – Quercetin Doesn’t Boost Weight Loss

Quercetin is a plant phenol found in dark coloured fruit and vegetables such as red onion, grapes and apples.

Although it has a low bioavailability it is often cited as a potent anti-inflammatory which can benefit metabolic and vascular health, as well as boost endurance performance.

For that reason you’ll find it marketed as both a health booster and performance-enhancing supplement.

If you’re looking at quercetin as your hope to speed up weight loss then you’ll be disappointed – there’s no evidence that it boost metabolism, fat loss or calorie burning.

And with so many other, more clinically proven ingredients out there we suggest you focus your attention away from this supplement until more scientific research is released.