Do Appetite Suppressants Work?

Appetite is an enormously complicated part of biology that’s influenced by a ton of different hormones and lifestyle factors.

Hormones like ghrelin, leptin, serotonin, cortisol, and others can increase or decrease your appetite, and they’re in turn influenced by your sleep, your activity, your macronutrients, your micronutrients, drinking, drugs, and more. The speed at which you eat your food affects your appetite. And then there are the psychological causes of appetite that lead some of us to eat when we’re not even hungry.

But we’re not going to get lost in the weeds, here — we’re here to talk supplements. Are there pills that can help you handle your appetite? There’s some pretty interesting science behind a lot of them, though many work in different ways.

Editor’s note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. It’s always a good idea to talk to your doctor before beginning a new fitness, nutritional, and/or supplement routine.

Credit: Salix, Licensed under Creative Commons 2.0.

1. The “Expand In Your Stomach” Stuff

The less space in your stomach, the less you’ll want to eat.

(Unless you have psychological issues contributing to your hunger, hormonal imbalances, or other issues. But we’re talking generally, here.)

Perhaps the most effective and reliable appetite suppressants are the least complicated: you eat them, they swell in your stomach, they make your stomach “think” it’s got more food than it does.

Glucomannan is a really interesting example. Used in a lot of fat burners like Leanbean, it’s made from the root of the Japanese konjac plant, it absorbs a ton of water, and an effective dose can be just 500 milligrams a day, though 1 gram is usually prescribed. A study published in the International Journal of Obesity found that two 500-milligram doses of glucomannan per day helped obese patients lose over 5 pounds in an 8-week period without any other changes to their diet whatsoever.(1) It’s also the main ingredient in shirataki noodles. Note that because it absorbs so much water it can produce thirst and it may reduce the amount of protein and fat absorbed from a meal, but besides that few side effects are reported.(2)

[For the best supplements that suppress appetite, check out our picks for the best women’s fat burner!]

psyllium husk
Credit: Bastique, Licensed under Creative Commons 3.0

Similar ingredients are psyllium husk, made from the seeds of the Plantago plant. They’re super high in soluble fiber and they form a thick gel when mixed with water. Studies have suggested that about two teaspoons of the stuff (6-ish grams) taken before a meal can significantly reduce the amount of calories consumed.(3)

Fenugreek, a herb from the legume factory, has been found to have similar effects for similar reasons.(4)

Note that these sorts of supplements can produce indigestion, particularly when not combined with water and food. But given the fact that they’re all natural and that side effects are reported relatively rarely, many feel they’re worth trying out.

garcinia cambogia

2. The Hormonal

Often sourced from the plant Griffonia simplicifolia, 5-HTP is what’s called a serotonin precursor. Serotonin is often considered a “happy hormone” but it has a few different effects, one of which is that it decreases appetite — or more accurately, it increases the satiety you get from the food you eat, according to Behavioural Brain Research.(5)

A lot of studies back this up, including a placebo-controlled, randomized study of 20 overweight women that found those who took 5-HTP in an oral spray significantly reduced their BMI and the circumferences of their arms and hips in just 4 weeks.(6)(7) Note that it can produce nausea in some folks.

The herb Caralluma fimbriata has a similar effect on serotonin, with several studies showing that about a gram of the plant’s extract per day resulted in significant reductions in BMI and waist circumference.(8)(9)

Finally Garcinia cambogia is often touted as a “miracle weight loss cure” because it appears to reduce belly fat.(10) Studies published in Molecular and Cellular Biochemistry and Diabetes, Obesity and Metabolism concluded that this Indonesian plant may increase serotonin levels, though it’s not hard to find studies that have found it to have no effect on weight, so the research is mixed.(11)(12)(13)(14)


3. Stimulants

Caffeine and nicotine are the bane of many, and we are not recommending anyone take up smoking, but the fact remains that these stimulants and others like them appear to have a marked effect on appetite.

Caffeine has a reputation for appetite suppression and while there’s decent evidence for this, more research is needed.(15) What’s much more widely accepted is that nicotine curbs hunger, which is why it’s not unheard of for folks to try chewing a small amount of nicotine gum to kill their appetite: your average nicotine gum has 4 milligrams per hit, but one milligram is enough for many nonsmokers to produce the effect. Research published in 2011 in Science found that this is because nicotinic receptors in the brain also activate neurons associated with peptide hormones that are linked to appetite.(16)


A 2005 study in Diabetes, Obesity and Metabolism also found that caffeine and nicotine together enhance one another’s appetite suppressant effects.(17) Yohimbine is another stimulant that’s linked to lower appetite, though it has more of a reputation for being tough to digest.(18)

Again, we’re not recommending nicotine — while it’s less addictive than cigarettes, which have thousands of other ingredients that make them more harmful, it’s still an addictive substance.

Wrapping Up

A regular exercise habit, good sleep hygiene, managing stress levels, and a diet that includes plenty of fiber, water, and protein will go a very, very long way to helping keep your appetite and “hunger hormones” in check. Nonetheless, when used judiciously and under the supervision of a doctor, you may find success by occasionally employing some of the products outlined here — just remember the “under the supervision” of a doctor part.


1. Walsh DE, et al. Effect of glucomannan on obese patients: a clinical study. Int J Obes. 1984;8(4):289-93.
2. Baer DJ, et al. Dietary fiber decreases the metabolizable energy content and nutrient digestibility of mixed diets fed to humans. J Nutr. 1997 Apr;127(4):579-86.
3. Brum JM, et al. Satiety effects of psyllium in healthy volunteers. Appetite. 2016 Oct 1;105:27-36.
4. Mathern JR, et al. Effect of fenugreek fiber on satiety, blood glucose and insulin response and energy intake in obese subjects. Phytother Res. 2009 Nov;23(11):1543-8.
5. Voigt JP, et al. Serotonin controlling feeding and satiety. Behav Brain Res. 2015 Jan 15;277:14-31.
6. Rondanelli M, et al. Relationship between the absorption of 5-hydroxytryptophan from an integrated diet, by means of Griffonia simplicifolia extract, and the effect on satiety in overweight females after oral spray administration. Eat Weight Disord. 2012 Mar;17(1):e22-8.
7. Hinz M, et al. 5-HTP efficacy and contraindications. Neuropsychiatr Dis Treat. 2012;8:323-8.
8. Kuriyan R, et al. Effect of Caralluma fimbriata extract on appetite, food intake and anthropometry in adult Indian men and women. Appetite. 2007 May;48(3):338-44.
9. Astell KJ, et al. A pilot study investigating the effect of Caralluma fimbriata extract on the risk factors of metabolic syndrome in overweight and obese subjects: a randomised controlled clinical trial. Complement Ther Med. 2013 Jun;21(3):180-9.
10. Hayamizu K, et al. Effects of garcinia cambogia (Hydroxycitric Acid) on visceral fat accumulation: a double-blind, randomized, placebo-controlled trial. Curr Ther Res Clin Exp. 2003 Sep;64(8):551-67.
11. Preuss HG, et al. Effects of a natural extract of (-)-hydroxycitric acid (HCA-SX) and a combination of HCA-SX plus niacin-bound chromium and Gymnema sylvestre extract on weight loss. Diabetes Obes Metab. 2004 May;6(3):171-80.
12. Ohia SE, et al. Safety and mechanism of appetite suppression by a novel hydroxycitric acid extract (HCA-SX). Mol Cell Biochem. 2002 Sep;238(1-2):89-103.
13. Anton SD, et al. Investigations of botanicals on food intake, satiety, weight loss and oxidative stress: study protocol of a double-blind, placebo-controlled, crossover study. Zhong Xi Yi Jie He Xue Bao. 2011 Nov;9(11):1190-8.
14. Kim JE, et al. Does Glycine max leaves or Garcinia Cambogia promote weight-loss or lower plasma cholesterol in overweight individuals: a randomized control trial. Nutr J. 2011 Sep 21;10:94.
15. Schubert MM, et al. Caffeine, coffee, and appetite control: a review. Int J Food Sci Nutr. 2017 Dec;68(8):901-912.
16. Mineur YS, et al. Nicotine decreases food intake through activation of POMC neurons. Science. 2011 Jun 10;332(6035):1330-2.
17. Jessen A, et al. The appetite-suppressant effect of nicotine is enhanced by caffeine. Diabetes Obes Metab. 2005 Jul;7(4):327-33.
18. Callahan MF, et al. Yohimbine and rauwolscine reduce food intake of genetically obese (obob) and lean mice. Pharmacol Biochem Behav. 1984 Apr;20(4):591-9.