Which Supplement to Pick for Muscle Growth, According to a Dietitian

Consuming enough calories is important to not only fuel your workouts but to increase muscle mass as well. This means consuming more calories than your body burns.

Building muscle also requires strength training.

In addition to calorie consumption and strength training, many supplements have been studied for their effect on exercise enhancement and weight gain.

Read on to learn about four different supplements that are backed by science in their potential to help with muscle growth.

1. Creatine Monohydrate

Creatine is a naturally occurring compound found mostly in skeletal muscle. It is formed from reactions involving the amino acids arginine, glycine, and methionine.

Creatine monohydrate is the primary form used for supplementation.

It is one of the most studied supplements on the market and is considered an ergogenic aid, a substance that enhances sports performance.

Creatine can enhance workouts by increasing energy, also called ATP, in the muscles. This contributes to increased power, strength, and muscle mass. (1)

When combined with strength training, creatine has an even better effect.

A 2003 review of 22 different studies confirmed that the combination of creatine with strength training can increase muscle strength by an average of 20%.

This was 8% more than the group who did not supplement creatine and only strength trained.

One of the key hormones for muscle growth is insulin-like growth factor-1 (IGF-1.)

Strength training increases the concentration of IGF-1. When supplementing creatine in combination with strength training, IGF-1 concentration in the muscle increases even more. (2)

This triggers the formation of new muscle. When new muscle grows, changes in the muscle fiber size take place. Creatine can enhance this process and increase the size of muscle fibers, contributing to overall muscle growth. (3)

One study on athletes over a 4-week period showed those who consumed 20 grams of creatine for 6 days followed by a maintenance dose of 2 grams per day for the rest of the study increased their maximal muscle strength and decreased muscle damage during training.

These effects were seen when combined with strength training. (4)

A dose of 0.3–0.8 grams per kilogram (approximately 0.13–0.36 grams per pound) of body weight is recommended and considered safe.

The safety of taking creatine has been established in over 1,000 studies in people from infancy to the elderly. (5)

The main side effects reported were water retention and weight gain due to increasing water in the muscles. This was particularly found at the beginning of taking the supplement.

2. Protein

Protein is the building block of your muscles and is a highly important factor for increasing lean body mass and maintaining it.

Protein supplements are increasingly common and can be an important part of growing muscle, especially if the overall intake of protein in the diet is on the lower end.

In general, experts recommend 1.4–2.0 grams of protein per kilogram of body weight (0.6–0.9 grams per pound) per day for those who are exercising. (6)

If you are not able to get enough protein through your diet, supplementing can be a great way to reach protein goals and increase muscle mass.

Some people also prefer the ease and convenience of having a protein supplement.

There are many kinds of protein supplements, such as whey, casein, pea, rice, and soy protein are examples.

Whey protein has a positive effect on strength, lean body mass, and overall weight gain in those who are strength training. (7)

Using a mix of whey and casein also has a positive effect on strength and lean body mass. (8)

Losing weight through dieting usually results in some muscle loss, but several studies have determined protein supplementation can help spare muscle loss when compared to those who are not supplementing.

This is important if trying to lose body fat while building muscle mass simultaneously.

An animal study showed that maximizing fat loss while preserving lean body mass can be influenced by protein intake, and supplementation may be helpful.

This study suggested that whey protein can have a complimentary fat-burning effect when combined with the right nutrients in the diet. (9)

Adding protein supplements is a safe way to ensure you are meeting your protein needs. However, there is such a thing as too much of a good thing.

According to one study, excess protein can be stored as fat and could increase the risk of kidney issues in those with kidney disease, and perhaps even in those with healthy kidneys. (10, 11)

Long-term high protein intake greater than 2 grams per kilogram of body weight should be avoided. (12)

3. Caffeine

Caffeine is an ergogenic aid that helps enhance performance.

It has an indirect effect on increasing muscle growth by improving endurance and strength during a workout.

There are a variety of sources of caffeine, such as coffee, espresso, tea, soda, chocolate, energy drinks, and supplements.

There has been some speculation about whether caffeine may inhibit muscle building.

This has been refuted in a recent animal study that showed caffeine did not inhibit muscle growth or decrease the body’s ability to make proteins necessary for this process. (13)

In fact, mice that were given caffeine in the form of coffee supplementation had an increase in muscle growth compared to the control group who did not supplement coffee.

The group who consumed coffee also increased protein expression, which directly affects how muscles function. (14)

Human studies have also confirmed a positive relationship between caffeine and muscle growth.

In a meta-analysis of 10 different human studies on both males and females, caffeine intake showed significant improvements in both strength and power.

The form of supplementation that was most common was capsules. Dosing ranged from 2–6 mg of caffeine per kg (0.9–2.7 mg per pound) of body weight ingested 45–60 minutes before exercise. (15)

The recommended maximum dose of caffeine is no more than 400 mg daily from all combined sources. (16)

However, not all forms of caffeine are safe. And caffeine isn’t appropriate for everyone.

Caffeine anhydrous is a more potent and concentrated powder form of caffeine and should be avoided. One teaspoon of pure caffeine powder is equivalent to 28 cups of coffee, making it very easy to get too much. (17)

Too much caffeine may cause disrupted sleep, anxiety, and jitters. (16)

Individuals metabolize caffeine at different rates, so it is best to find out what amount works best for you without causing side effects.

4. Leucine

Leucine is one of the 20 amino acids that make up protein. It is specifically one of the three branched-chain amino acids.

Branched-chain refers to the chemical structure of these amino acids and includes leucine, valine, and isoleucine.

In animal studies, leucine has shown a significant effect on increasing muscle mass when combined with strength training. (18)

Including 3–5 grams of leucine with meals can help preserve muscle by decreasing breakdown and increasing protein synthesis.

This is the amount found in about 25–30 grams of protein and is helpful for maintaining and gaining lean body mass. (19)

There are a few ways to increase leucine intake with supplementation.

Supplementing 3 grams per day of the leucine metabolite β-hydroxy-β-methylbutyrate (HMB) with strength training increases lean body mass and strength.

HMB improves strength gains by decreasing muscle breakdown and lessening muscle damage. (20)

Another way to increase leucine is to supplement with branched-chain amino acids (BCAAs). These will provide leucine as well as the other two BCAAs, isoleucine and valine.

Protein supplements typically contain all of the amino acids, including leucine, and are another way to improve muscle growth.

The leucine content of protein supplements varies between 5%–10%, with animal protein containing the highest content of leucine. (21)

Taking leucine by itself as a supplement is another option.

The amount needed will vary based on activity level and goals. Including 45–55 mg of leucine per kilogram (20–25 mg per pound) of body weight can be beneficial to optimize protein synthesis, which helps build muscle.

For those that are more active, even higher amounts are suggested. (22, 23)

Frequently Asked Questions

The Bottom Line

Certain supplements can be helpful for increasing muscle mass, but not without the combination of weight training and consuming enough calories.

Creatine, protein, caffeine, and leucine are four supplements that have evidence-based research on enhancing performance and improving the body’s ability to gain muscle.

It is important to take the right dose of muscle enhancing supplements, which vary based on your activity level, health goals, and metabolism.

Always talk to your healthcare provider before starting a new supplement.