From average gym-goers to professional athletes, pre-workout supplements have become a billion-dollar business. Many people rely on pre-workout supplements to boost workout efficiency, output and overall results so they can reach that next desired level of fitness. But choosing a pre-workout supplement can be difficult. With a wide range of workout shakes, energy gels and other supplements on the market, there is some risk for potential side effects if the supplements aren’t specific enough to the individual or cleared by a physician.

Typically, pre-workout supplements include some or a combination of caffeinecreatineamino acidsbeta-alanine and nitric oxide agents that together claim to do more than each individual ingredient on their own. While many supplement shakes, gels and capsules also include other individual ingredients, weighing the benefits and risks of pre-workout supplements with caffeine has some questioning its effectiveness.

Caffeine in Sports

Since being removed from the World Anti-Doping Agency (WADA) Prohibited List, caffeine has become one of the most commonly used ergogenic ingredients in workout supplementation. Ergogenic means enhancing physical activity, stamina or recovery. Between 1984-2004, WADA originally prohibited the use of caffeine in sports because of its enhancement-like effects but later removed it to eliminate those who had consumed coffee or other caffeinated beverages from testing positive.

The Benefits of Caffeine

Caffeine is mostly a natural substance derived from over 60 types of plants but there are also other forms of synthetic caffeine. Pre-workout supplements use the stimulant-effect of caffeine to improve strength, endurance, power output, recovery efforts and overall results—especially when it comes to athletic performance. By increasing circulation as well as stimulating the central nervous system, caffeine triggers the synapses in the brain to increase alertness and energy. According to one study, ingesting caffeinated gelatin capsules was shown to improve fatigue resistance during various forms of exercise such as time trial cycling, sprinting and repeated sprinting. This would support the idea that caffeine also contributes to longer workouts and improved endurance without the potential risk of burning out.

How Much Caffeine Is Too Much?

The Food and Drug Administration (FDA) recommends not exceeding 400mg of caffeine a day. This is equivalent to ingesting 4-5 cups of caffeinated coffee. Most pre-workout supplements contain anywhere from 60mg to 419mg per serving and many do not list their caffeine content on the label. The effects of caffeine can begin within an hour of consumption and last six or more hours. But because everyone’s metabolism, overall health and caffeine sensitivity are not the same, it’s hard to determine how well or whether caffeine is tolerated at all. It’s suggested to avoid going over FDA's maximum recommended daily allowance because doing so has potentially dangerous consequences. Also, there is limited research on the effects of taking caffeine-stimulating supplements daily or on a long-term basis.

Side Effects of Caffeine

Such potential side effects of using caffeine as an ergogenic aid before workouts may include the following:

  • Anxiety
  • Insomnia
  • Digestive problems
  • Increased heart rate
  • Irregular heart rate
  • Diuretic effect
  • Muscle tremors
  • Fatigue
  • Dizziness
  • Dependency 

When to Avoid Caffeine

Consult a physician before using workout supplements with caffeine or using supplements altogether. If any of the below conditions exist, avoid caffeine unless a physician has approved its use.

  • Pregnancy: Some observational studies have concluded that caffeine in excess during pregnancy may be associated with growth restriction, reduced birth weight, preterm birth or stillbirth.
  • Breastfeeding: Excess caffeine ingested by the mother enters the breast milk, which can agitate the baby and disrupt its sleep.
  • High blood pressure: While caffeine may increase blood pressure, some studies suggest it’s okay in moderate use. Consult a physician before consuming.
  • With prescription medications: Caffeine can interact with ephedrine, adenosine, antibiotics and other medications. Consult a physician before consuming.
  • Anxiety: Because of caffeine’s energy-boosting properties, it may increase anxiety symptoms to a higher level in those who have anxiety-related health conditions.
  • Depression: Because caffeine has a drop-off effect after it has gone through the body, it can contribute to dependency and mood disorders.
  • Digestive conditions: Excess caffeine can sometimes exacerbate digestive issues like upset stomach, diarrhea and IBS.
  • Heart conditions: Excess caffeine consumption can elevate heart rate, which may intensify symptoms of arrhythmias or irregular heart rates.

Are Stimulant-free Supplements as Effective as Ones with Caffeine?

While using pre-workout supplements with caffeine can be done safely and effectively, for those who seek to achieve the same workout results there’s another option. Stimulant-free pre-workout shakes, capsules and energy gels continue to have a majority of the same ingredients as those with caffeine, minus the stimulants. They also often include different amino acids and other natural ingredients to mimic the same intense focus, energy and pumps that caffeine supports. Going stimulant-free can also decrease the jitters and help with sounder sleep for improved muscle recovery. Along with a healthy diet, stimulant-free pre-workout supplements continue to support improving workout output, recovery and results with long-lasting energy and efficiency.