The Pros and Cons of Pre-Workout Supplements (Science-Based)

Caffeine has multiple downsides, especially when taken in excess. Side effects of pre-workout include an increased heart rate, nausea, anxiety, headaches, and jitteriness [4].

Most pre-workout supplements contain caffeine in excess (reportedly more than the amount in a cup of coffee), making these side effects more common among pre-workout users.

To curb this effect, I always advise clients to start with a small dose before graduating to levels they can tolerate. If need be, I recommend pre-workout supplements with no caffeine.

4. Digestive Upset

Bloating and diarrhea are common with pre-workout supplements. These issues often stem from ingredients like caffeine, creatine, sodium bicarbonate, and magnesium, especially in high doses [5].

Also, not using enough water can concentrate these elements, leading to diarrhea [6]. Having looked at pre-workout supplement pros and cons, let's dive into some useful tips and precautions for taking them.

Related: Does Pre-Workout Cause Bloating?

Yes, you should use pre-workout supplements if you want to reap maximum benefits from your workouts, granted you’re not allergic to the ingredients or have certain medical conditions.

However, to enjoy the full benefits of a pre-workout, I always advise my clients to consider addressing other factors such as diet, sleep quality, and hydration before turning to these supplements.

Pre-workout supplements boost energy and focus, increase muscular endurance, strength and stamina, and delay fatigue [7].

Ingredients such as caffeine, creatine, L-citrulline, and dendrobium extract (Dendrobex™) are believed to achieve these effects by increasing time to exhaustion, preserving muscle glycogen content, and decreasing perceptions of pain and effort [8].

Just like nitric oxide, creatine is also produced naturally in the body and plays a massive role in muscular strength and energy production.

A healthy pre-workout formula has creatine monohydrate as part of its ingredients, although it's often sold as a standalone product to bodybuilders, weightlifters, and power athletes.

According to the International Society of Sports Nutrition, supplementing the body with creatine boosts its natural supply, thereby improving strength, workout intensity, athletic performance, muscle mass, and recovery time [12].

4. Beta-Alanine

Pre-workout formulas also contain beta-alanine, an amino acid that prevents the build-up of lactic acid in the muscle tissue. The purpose of beta-alanine is to increase muscle endurance (muscle’s ability to work harder and for longer) and to delay muscle fatigue [13].

Related: Why Does Pre-Workout Make You Tingle?

5. Branched-Chain Amino Acids (BCAAs)

Pre-workout formulas contain BCAAs, usually included to increase muscle growth and decrease muscle soreness [14]. Other ingredients you’re likely to find in a pre-workout supplement include L-Taurine and L-Leucine.

Now that we know what to expect in a pre-workout, let's get into the crux of the matter. Below are the pros and cons of pre-workout supplements.

Some pre-workouts have L-carnitine, an essential compound that aids the muscle in fat-burning [15].

Other components in a pre-workout supplement prevent the formation of fat and suppress eating by stimulating the production of the GLP-1 hormone, which regulates appetite [16].

4. Muscle Strength

Creatine is an essential ingredient found in most pre-workout supplements. Its work is to enhance strength by increasing biochemical mechanisms that give you that energy boost you need during a workout.

The result is a boost in strength, endurance, and, eventually, muscle mass, as per NCBI [17]. Additionally, the nitrates in most pre-workout supplements allow the body to carry amino acids to your muscles, resulting in increased strength [18].

5. Muscle Growth and Lean Body Mass

As mentioned earlier, pre-workouts contain BCAAs, one of the essential amino acids necessary for protein synthesis. Pre-workouts also contain citrulline, another amino acid that boosts blood flow to the muscles [19].

When you undergo stress training, oxygen levels are elevated, and nutrients are carried to the muscles to promote muscle gain.