Still Hungry? Appetite Suppressants

If you want to lose weight, you must consume fewer calories than you burn.  Then your body will begin to break down energy reserves such as fat for fuel.  Ideally, weight loss should occur by reducing calorie consumption and also increasing the amount of calories burned daily.  Appetite suppressants are types of weight-loss supplements which help you reduce calorie consumption by blocking your hunger and/or making you feel full for longer after eating.

Why We Feel Hungry

In order to understand how appetite suppressants work, one must have a basic understanding of how appetite is regulated in our bodies.  For the past decade, appetite regulation has become the subject of increasingly more research.  Despite all of the research which has been done on appetite control, experts have yet to fully understand the complex system of hormones, neurotransmitters, and systems which determine when we feel hungry or full.

Even though we feel hunger in the stomach, appetite is primarily controlled by the hypothalamus in the brain.  The hypothalamus is also in charge of regulating emotions, sexual satisfaction, and pleasure, which explains why these sensations can all be associated with eating.  When the level of glucose in our blood decreases, signals are sent to the brain which trigger hunger.  Hunger is basically a command from our brain to go search for more “fuel”.  When we eat food, our blood sugar levels elevate thus causing levels of certain hormones to increase which ultimately triggers our brains to “turn off” hunger.  Food consumption also triggers the brain to release neurotransmitters, such as serotonin, which make us feel content.   This feeling of content we get from eating can be viewed as our bodies’ way of rewarding us for survival.

How Appetite Suppressants Work

Many appetite suppressants, particularly those which are prescription-only, work by acting on the brain so hunger is blocked.  Most stimulants suppress appetite in this manner by affecting neurotransmitters like norepinephrine and essentially putting the body in a state of stress. While under stress, the body increases its energy-burning capabilities and blocks hunger. Ephedrine and amphetamines are just two examples of stimulant appetite suppressants.  These have largely been banned for weight-loss purposes because of their potential dangerous effects and risk of addiction.

Not all appetite suppressants which affect the brain are stimulants.  Drugs which affect serotonin levels (the neurotransmitter which makes us feel content after eating a meal) have been used for suppressing appetite.  However, these have proved ineffective for long-term appetite suppression.  Recently, drugs which affect cannibinoid receptors have been approved as prescription appetite suppressants for treating obesity.

In recent years, many new, “natural” appetite suppressants have hit the market.  These claim to work by making you feel full for longer after eating a meal.  Many of the most popular of these natural appetite suppressants contain soluble fiber (such as from cactus).  When the supplement is taken with food, the fiber will bind to the food and slow down the conversion of carbohydrates into glucose.  Because the energy from the food is being released slowly, one will feel full for longer.  When choosing these so-called natural appetite suppressants, one needs to be very careful.  They work in many different ways and many are just stimulants like caffeine or green tea extracts.  While powerful for short-term appetite suppression, they can have harmful effects immediately or in the long run.

One of the most recent and most promising appetite suppressants is leptin.  Leptin is a protein which gets released by fat cells when one eats too much.  When levels of leptin get too high, the hypothalamus turns off hunger cravings.  Studies have found that many obese people have a condition called leptin insensitivity in which their brains do not turn off hunger until leptin levels get very high.  There are now a few appetite suppressant supplements available which supposedly increase the body’s sensitivity to leptin.  However, much more research is needed before leptin sensitivity supplements can be promoted as a cure for overeating.

Dangers of Appetite Suppressants

Many of the appetite suppressants available are stimulants.  Even the seemingly benign-sounding “natural” appetite suppressants may just contain a glorified version of caffeine (Caffeine for weight loss: can a cup of joe really help you shed pounds?).  Stimulants can sometimes be effective for short-term weight loss but come with many risks including high blood pressure, heart attacks, and psychological problems.  There is also a risk of addiction and withdrawal effects.  The non-stimulant appetite suppressants which affect the brain, such as selective serotonin-reuptake inhibitors (SSRIs), can have psychological effects, sleeping problems, and loss of sex drive.  Some SSRI appetite suppressants were removed from the market because of their potentially deadly effects.

There are many safe appetite suppressants available over the counter.  However, it is important to note that many of these have not been proven effective in suppressing appetite.

Do Appetite Suppressants Really Work?

Nutritionists will quickly tell you that weight loss should occur from calorie reduction and also an increase in activity.  If you try to lose weight just by cutting calories, then it will be very difficult to lose weight.  Further, using appetite suppressants to endure a crash diet can result in serious harm to your body, like loss of muscle mass.  You can read more about the dangers of crash diets here. (Does eating less really help weight loss?)

Stimulant appetite suppressants are largely ineffective for long-term weight loss.  After using a stimulant for a prolonged period of time, the body will build up a tolerance to the substance and it will no longer produce the same benefits.  Once stimulant use is stopped, they can also produce withdrawal effects which counter weight loss, such as increased appetite and a reduced metabolism.  Many people who use stimulant appetite suppressants will just gain back any weight loss during their diet and may even gain back more than they lost.  SSRIs were formerly prescribed for obesity but they too also proved ineffective for long-term weight loss.  Many people taking SSRIs for obesity experienced increased appetite and weight gain after prolonged use.

Many people have reported positive benefits from the natural, non-stimulant appetite suppressants like Hoodia Gordonia.  However, it is hard to tell how much of these so-called benefits are just hype as no significant studies support the effectiveness of Hoodia and most other natural appetite suppressants. It also must be noted that eating less can cause the metabolism to become slower.  That is why it is so important to still eat healthy, low-calorie meals while dieting with an appetite suppressant.


Stallone, Daryth D. and Albert J. Stunkard. “Long-term use of appetite suppressant medication: Rationale and recommendations.” Drug Development Research 26.1 (1992): 1-20. Web.

Roma Paumgartten, Francisco José. “Long-term health benefits of appetite suppressants remain unproven.” Revista de Saude Publica 45.6 (2011). Web.

Boeree, C. George, Dr. “The Emotional Nervous System.” www.webspace.ship.edu. Shippenburg University. 2009.  Web.

Wurthman, Judith, PhD. “The Antidepressant Diet.” PsychologyToday.com. Psychology Today. 5 Aug 2010. Web.


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