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Could Aspartame Cause Anxiety and Depression?

Cleo Addams has an M.S. Degree in Natural Health & Nutrition. She enjoys researching and writing in her free time.

Aspartame is the top artificial sweetener in diet sodas.

Aspartame is the top artificial sweetener in diet sodas.

Aspartame was invented in 1965 by a chemist named James Sclatter and was first approved as an artificial sweetener in 1981 by the Food & Drug Administration (FDA). It is made up of three chemicals: aspartic acid, phenylalanine, and methanol.

The one chemical in aspartame that we want to focus on is phenylalanine. Phenylalanine is proven to reduce the serotonin levels in the brain if consumed in large amounts over an extended time frame, i.e. consuming diet drinks or foods sweetened with aspartame.

In one study, mice were given various doses of aspartame for 30 days. After 30 days, the mice were found to have decreased serotonin in several regions of the brain. The study states, "An increased supply of phenylalanine may be responsible for a decrease in tryptophan uptake by the brain tissue or for a depression in tryptophan conversion to serotonin."

Keeping a healthy level of serotonin is very important because it regulates appetite, energy levels, sleep, mood, libido, anxiety, and impulses. When a person has anxiety or depression, it is the result of decreased serotonin levels in the brain.

Knowing how aspartame affects the serotonin levels in one's brain, it could be said that if a person consumes multiple aspartame-sweetened drinks or foods each day over a long length of time, then it is possible that one might develop a type of anxiety disorder or even depression. (Of course, the length of time will vary depending on how much aspartame an individual consumes.)

If you’re suffering from anxiety or depression, please take a moment to look at what you’re eating and drinking. If you find that you’re consuming a large amount of aspartame each day, I would encourage you to permanently eliminate it and adopt a healthier diet full of veggies, fruits, and whole grains. Instead of soft drinks, drink water or low-sugar juices and/or smoothies.

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Other Potential Side Effects from Aspartame

  • weight gain
  • headaches
  • migraines
  • seizures
  • vision problems
  • sleep problems
  • fatigue

Other Factors That May Contribute to Anxiety Disorders and/or Depression

Putting aspartame aside for a moment, it's important to note that there are also other factors that could cause anxiety disorders and/or depression. Again, these also work by reducing serotonin levels in the brain.

  • Alcohol
  • Caffeine
  • Cigarette smoking
  • Dietary deficiencies (poor diet lacking required amounts of vitamins and/or minerals)
  • Diet pills
  • Infections
  • Lack of exercise
  • Lack of sunlight
  • Stress and anger (high cortisol levels)
  • Genetics (hormone imbalances, issues converting the amino acid tryptophan into serotonin)

Aspartame and the Brain


  • US National Library of Medicine National Institutes of Health, Effects of repeated doses of aspartame on serotonine and its metabolite in various regions of the mouse brain, (Accessed 4/29/18)
  • Integrative Psychiatry, What is Serotonin?, (Accessed 4/29/18)
  • Healthline, The Truth About Aspartame Side Effects, (Accessed 4/29/18)
  • Mercola, Aspartame: By Far the Most Dangerous Substance Added to Most Foods Today, (Accessed 4/29/18)
  • Wikipedia, Aspartame, (Accessed 4/29/18)


The information in this article is not intended or implied to be a substitute for professional medical advice, diagnosis or treatment. All content, including text, graphics, images and information, contained or available in this article is for general information purposes only. You are encouraged to confirm any information obtained from this article with other sources, and review all information regarding any medical condition or treatment with your physician. Never put off or delay seeking professional medical or nutritional advice and/or treatment.

The bullet lists in this article are not extensive.

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2020 Cleo Addams

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