Short answer: Three common pre-workout ingredients have solid evidence. Caffeine at 3 to 6 mg per kg of body mass improves many kinds of performance. Creatine builds muscle stores over days and supports high-intensity work. Beta-alanine at 4 to 6 g a day for several weeks helps efforts lasting 1 to 4 minutes. The FDA does not approve supplements before sale.
The old version of this post covered five ingredient groups loosely. This one focuses on the three with ISSN position stands, gives the studied doses, and explains what "not FDA approved" actually means.
What does caffeine do in a pre-workout?
From the International Society of Sports Nutrition (ISSN) position stand on caffeine (Guest and colleagues, 2021):
- Caffeine improves performance in many but not all studies, with small to moderate benefits for muscular endurance, movement speed, strength, sprinting, jumping, and throwing.
- Aerobic endurance shows the most consistent moderate-to-large benefit.
- Effective doses are 3 to 6 mg per kg of body mass. The minimum may be as low as 2 mg/kg. Very high doses around 9 mg/kg bring a high rate of side effects and aren't needed.
- The most common timing is about 60 minutes before exercise, though gums may act faster than capsules.
- Individual responses vary, including effects on sleep and anxiety.
The FDA cites 400 mg a day as an amount not generally associated with negative effects for most adults, with wide variation in sensitivity. It estimates toxic effects such as seizures can occur with rapid intake of about 1,200 mg.
What does creatine do?
From the ISSN creatine position stand (Kreider and colleagues, 2017):
- Supplementation raises muscle creatine stores, which may explain improvements in high-intensity exercise performance and greater training adaptations.
- Short- and long-term use, up to 30 g a day for 5 years, was safe and well tolerated in healthy people studied.
- Because it works through stored creatine, daily intake matters more than taking it right before training.
What does beta-alanine do?
From the ISSN beta-alanine position stand (Trexler and colleagues, 2015):
- 4 to 6 g a day for at least 2 to 4 weeks raises muscle carnosine, an internal buffer.
- Benefits are most pronounced in efforts lasting 1 to 4 minutes.
- The only reported side effect is tingling (paraesthesia), which smaller divided doses of about 1.6 g or sustained-release forms can reduce.
- More research is needed on its effect on strength.
A single scoop before training won't load beta-alanine. It's a daily, weeks-long ingredient.
How should you read a pre-workout label?
- Find the caffeine per serving and compare it to 3 to 6 mg per kg of your body weight and your total daily intake from coffee or other sources.
- Check creatine and beta-alanine amounts. Compare them to the studied doses above.
- Watch for proprietary blends. The FDA notes ingredients in a proprietary blend don't need individual amounts listed, so you may not know the dose.
- Start with a partial serving to see how you respond, especially to caffeine.
- Avoid late-day caffeine if it affects your sleep.
Are pre-workout supplements regulated?
Differently from drugs. According to the FDA, it does not have authority to approve dietary supplements before they are marketed, generally does not approve their claims, and does not test them before sale. Manufacturers are responsible for safety and labeling, and the FDA can act against adulterated or misbranded products after they reach the market. The FDA advises talking with a health care professional before using a supplement, since some interact with medicines.
Do you need a pre-workout?
No. The ISSN protein position stand notes active people can meet protein needs from whole foods, and caffeine is available in coffee. Training, food, and sleep matter more than any scoop. For eating around training, see our 3 week diet plan for lifters. If you train intervals, our HIIT guide covers how hard efforts fit your week.
FAQ
How much caffeine is in an effective pre-workout dose?
The ISSN says caffeine consistently improves performance at 3 to 6 mg per kg of body mass, most often taken about 60 minutes before exercise. Very high doses around 9 mg/kg bring more side effects without needing them.
How much caffeine is too much?
The FDA cites 400 mg a day as an amount not generally associated with negative effects for most adults, and notes toxic effects like seizures can occur with rapid intake of about 1,200 mg.
Does creatine need to be taken before a workout?
Creatine works by raising muscle creatine stores over time, so daily intake matters more than timing. The ISSN reports doses up to 30 g a day for 5 years were safe in healthy people studied.
Why does beta-alanine make my skin tingle?
Tingling, called paraesthesia, is the only reported side effect in the ISSN position stand. Splitting into smaller doses of about 1.6 g or using sustained-release forms can reduce it.
Does the FDA approve pre-workout supplements?
No. The FDA does not have authority to approve dietary supplements before they are marketed, and does not test them before sale. Manufacturers are responsible for safety and labeling.
Next rep
Pull the label on your current pre-workout and do the math on caffeine per kg.
Sources
- ISSN position stand: caffeine and exercise performance (Guest et al., 2021)
- ISSN position stand: creatine supplementation (Kreider et al., 2017)
- ISSN position stand: beta-alanine (Trexler et al., 2015)
- FDA: Spilling the Beans, how much caffeine is too much?
- FDA: Questions and answers on dietary supplements