Center for Research on Ingredient Safety

What are stimulants?

Stimulants refer to a wide variety of drugs and compounds that can boost mood, increase one’s ability to focus, and improve vigor and sociability. Some stimulants have ergogenic effects, meaning they can enhance performance. 
 
We can find stimulants in prescribed medications, foods, beverages, dietary supplements, and other human-made substances. 

What are common stimulant ingredients found in foods, beverages & dietary supplements? 

In this post, we focus on ingredients found in foods, beverages, and dietary supplements that are thought to be stimulants, including:

• B-complex vitamins 
• Caffeine
• Carnitine
• Ginseng
• Guarana
• Taurine

You can find many of these ingredients in coffee, teas, energy drinks, soda pops, drink flavor enhancers, chocolate, and dietary supplements like caffeine pills. 
 

B-Complex vitamins 

What are B-complex vitamins? 

B-Complex vitamins typically consist of 8 B-vitamins grouped together:

• B1: Thiamine
• B2: Riboflavin
• B3: Niacin
• B5: Pantothenic acid
• B6: Pyridoxine
• B7: Biotin
• B9: Folate
• B12: Cobalamin 

These water-soluble vitamins are necessary for optimal body function and are found in the food we consume. Most healthy adults meet their B-vitamins threshold by eating a healthy, balanced diet. 

Some individuals, such as vegetarians, vegans, and pregnant women, may need to take B-vitamin supplements to meet their health needs (1,2,3).
 

Where are B-complex vitamins found? 

In our everyday diet, we find B-vitamins naturally in the food we consume, such as leafy green vegetables, beans, peas, fish, eggs, poultry, and more. 
 
Manufacturers add B-vitamins to energy drinks in excess of needed daily intake.

What are B-complex vitamins supposed to do? 

Many energy drinks claim that B-vitamins can boost mental alertness and focus, and even improve mood.

Do B-complex vitamins work?  

We know that a lack of B-vitamins can cause diseases and anemia. Still, research hasn’t concluded that B-vitamins alone in energy drinks are solely responsible for stimulating health effects (1,2,3). 

Are B-complex vitamins safe? 

Our bodies only need a specific amount of B-vitamins to remain healthy. When we consume more B-vitamins than what our bodies need, our bodies will excrete the unneeded vitamins via our urine. While we can consume a large dose of B-vitamins without harm, it does not mean it’s harmless at any dose (remember, the dose makes the poison) nor does it mean we will reap any benefits from consuming B-vitamins in excess. 
 

Caffeine

What is caffeine? 

Caffeine is a natural or synthetic psychoactive drug found in some foods, beverages, dietary supplements, and medication (1,2). 

Where is caffeine found?

You can find natural caffeine in coffee, tea, and chocolate.

Synthetically created caffeine is often found in soda pop, energy drinks, dietary supplements, and medications. 

What is caffeine supposed to do? 

Caffeine is a known stimulant that can increase alertness, improve energy, and elevate one’s mood. It’s also known to increase aerobic endurance and improve reaction times (1,2). 

Does caffeine work?

Yes, researchers have shown that caffeine is a highly effective stimulant capable of many health claims, including improving energy levels, cognitive processes, alleviating sleep deprivation symptoms, and more (1,2).

Is caffeine safe?

Caffeine is safe when consumed in moderation. There are known side effects of caffeine consumption, including increased heart rate, blood pressure, anxiety, and arrhythmias. If consumed in excess, caffeine can cause serious side effects, including seizures, tachyarrhythmias, and more.
 

Carnitine

What is carnitine? 

Carnitine is the break-down of the essential amino acid, lysine. It supports metabolism functions in the body. 

Where is carnitine found?

Carnitine is naturally produced in our bodies from the foods we consume. Some manufacturers add synthetic carnitine to beverages and supplements. 

What is carnitine supposed to do?

When naturally produced in our bodies, carnitine aids in metabolic functions, including the transport of long-chain fatty acids.
 
When paired with other stimulant ingredients like caffeine, it’s thought to improve exercise performance and fat loss.  

Do carnitine supplements work?

In healthy individuals, carnitine produced in the body works as expected to support metabolic function. 
 
As an ingredient in energy drinks, there is little evidence to suggest that carnitine alone produces increased performance and fat loss. Rather, caffeine is most likely responsible for the outcome. 

Is carnitine safe?

Carnitine is safe to consume even at high doses. However, it can cause mild gastrointestinal side-effects, such as nausea and vomiting. 
 
When consumed in substantial doses, more than 3 grams per day, carnitine can cause “fishy” body odor. So, it’s best to consume carnitine in moderation.  
 

Ginseng

What is ginseng? 

Ginseng is an herb that has been used throughout East Asian countries as a health supplement. Typically, the ginseng plant’s root is harvested and used to create herbal supplements.

Where can I find ginseng? 

Ginseng plants grow around the world. You can find the ginseng as an ingredient in energy drinks, teas, herbal supplements, and more.

What is ginseng supposed to do?

Many believe that ginseng boosts the immune system and can improve physical and mental health. It’s also thought to reduce stress and have anti-inflammatory properties (1,2).

Does ginseng work?

As an ingredient in energy drinks, there is little evidence to suggest that ginseng produces increased mental or physical performance. Rather, caffeine is most likely responsible for the outcome. 

Is ginseng safe?

Ginseng is safe to consume in moderation. If consumed at high levels, the ingredient may cause hypertension, diarrhea, and disrupted sleep.
 

Guarana 

What is guarana? 

Guarana is a plant native to Brazil that produces fruit with edible seeds. The seeds naturally contain caffeine and significant amounts of saponins, flavonoids, and tannins. Saponins and tannins are thought to possess antioxidant properties (1,2). 

Where is guarana found? 

We can find guarana in many energy drinks, supplements, and teas. 

What is it supposed to do? 

Many believe that guarana improves cognitive performance, reduces mental fatigue, improves mood and physical performance, and boosts weight loss (1,2,3).
 
It’s also thought that the caffeine is released more slowly, which can produce a subdued, yet longer-lasting stimulatory effect. 

Does guarana work?

Studies support that guarana can improve alertness, reduce mental fatigue, and boost mood. Limited animal and human studies suggest that it can also improve physical performance; however, the results are short-term (1,2,3). 

Is guarana safe?

Guarana is safe to consume in moderation. However, excess guarana consumption can cause side-effects similar to excess caffeine consumption such as anxiety and arrhythmias. 
 

Taurine  

What is taurine? 

Taurine is a compound our bodies require to support our digestive and cardiovascular function as well as our skeletal, muscular, and central nervous system (1,2). 

Where is taurine found? 

Taurine is found naturally in the foods we consume. Most healthy adults meet their daily requirements by eating a healthy, balanced diet. 

We can find synthetic taurine in energy drinks and supplements. 

What is taurine supposed to do? 

Synthetic taurine found in energy drinks and supplements is thought to boost physical and cognitive performance. 

Does taurine work? 

There is limited evidence suggesting that additional taurine supplements found in energy drinks improve physical performance and boost cognitive function. More likely, caffeine is responsible for the cognitive boost found after consuming drinks and supplements containing taurine and caffeine.

Is taurine safe? 

Taurine is safe to consume in moderation. 
 

The good news. 

Stimulants found in energy drinks, foods, supplements, and other beverages are safe to consume in moderation for adults. Research continues around these key ingredients to help us better understand if and how these ingredients impact our bodies and cognitive function.