Though weight loss is a very common goal, many people actually want to gain weight.

Some common reasons include improving daily functioning, looking more muscular and enhancing athleticism.

Typically, those who want to gain weight should focus on gaining muscle. It’s usually healthier to gain most of your weight as muscle rather than fat.

While food and exercise are most important for gaining muscle, supplements may also help by providing calories and protein or by allowing you to exercise harder.

Here are 4 supplements that may help you gain muscle.

Best Weight Gain Supplements

Most people know that protein is an important muscle component.

Several studies have shown slightly more muscle gain in exercising adults who consume protein supplements as part of their diet (1, 2).

However, the most important factor is likely your total daily protein intake rather than whether it comes from foods or supplements (3, 4).

As a general recommendation, the Institute of Medicine suggests that 10–35% of your daily calories should come from protein (5).

Many scientists agree that a daily intake of 0.6–0.9 grams per pound (1.4–2.0 grams per kg) of body weight per day is appropriate to support muscle growth in active adults (6).

If you are able to consume this recommended amount of protein from whole foods, protein supplements are not necessary.

However, many people consider supplements in the form of shakes or bars a convenient way to fit more protein into a busy schedule.

One way to help determine if you are eating enough protein without supplements is to track your diet on a few typical days. You can use free resources such as the USDA SuperTracker, MyFitnessPal or other similar apps or websites.

It’s also important to realize that eating a high-protein diet will not cause weight gain unless you consume enough calories overall.

In fact, some studies show that high-protein diets can promote fat loss, possibly by making you feel more satisfied after eating and decreasing the amount you eat (7, 8).

Summary Protein is very important for muscle growth. The most critical aspect is likely the total amount you consume each day. An intake of 0.6–0.9 g/lb (1.4–2.0 g/kg) is recommended. Your protein intake can come from either food or supplements.

Creatine is one of the most-researched supplements and one of the few sports supplements with very strong research support (9).

This molecule is found naturally in your cells and in some foods.

When taken as a supplement, the creatine content in your muscles can increase beyond normal levels (10, 11).

Creatine has several important functions in your body, including rapid energy production (12).

A substantial amount of research has shown that creatine supplements can improve exercise performance and muscle gain over time (9, 13).

While several different types of creatine are available, creatine monohydrate has the most research backing it as safe and effective (14).

When taking creatine, it’s typically recommended to begin by taking a loading dose of approximately 20 grams per day, split into four servings, for 5–7 days (9, 15).

After this initial period, a maintenance dose of approximately 3–5 grams per day can be taken indefinitely.

Summary Creatine is a go-to supplement for muscle and weight gain. Many studies have demonstrated that it can help improve exercise performance and muscle gain over time. Several types are available, but creatine monohydrate is currently recommended.

To gain weight, you need to consume more calories than your body needs for normal functioning. However, how much extra you have to eat can vary between people (16, 17).

Weight gainers are a broad group of high-calorie supplements that are marketed to those who have trouble gaining weight.

Similar to protein supplements, there is nothing magical about these supplements. They simply are a convenient way for some people to get more calories.

Typically, weight gainers are shakes very high in carbohydrates and high in protein.

For example, one popular supplement contains 1,250 calories, 252 grams of carbohydrates, and 50 grams of protein per serving.

While adding weight gainers to your diet can certainly increase the number of calories you are eating, some people find the taste and consistency of these products unpleasant.

Though these supplements can be convenient when you’re on the go, another option is simply to eat more real food, which would also provide other beneficial nutrients.

Summary Weight gainers are high-calorie products that contain large amounts of carbohydrates and protein. These products can help you gain weight if added to your normal diet, but they are not better than eating more real food.

Very few, if any, supplements lead to substantial weight and muscle gain without exercise.

However, several supplements exist that may help you exercise harder, which could lead to more muscle gain over time.

Caffeine

Caffeine is consumed widely around the world. Active people often take it before exercise to improve exercise performance.

Research has shown that caffeine is indeed effective at enhancing exercise performance.

For example, it can improve power output, the body’s ability to produce force quickly, which is important for activities such as weight training, sprinting and cycling (18).

Over time, exercising harder due to caffeine consumption could lead to better muscle gain. However, this would only occur if adequate calories and protein are consumed.

Citrulline

Citrulline is an amino acid that is produced in your body and found in foods (19, 20).

One of its functions is to increase blood flow to your body’s tissues (21).

Several studies have found that the amount of exercise performed in a single session may be increased when taking this supplement (22, 23, 24).

Long-term research is limited, but this supplement could help with muscle gain over time if it allows you to perform more overall work during exercise.

Beta-Alanine

Beta-alanine is another amino acid produced naturally in your body. Among other functions, it can help your muscles fight fatigue during exercise (25).

Taken as a supplement, beta-alanine may help improve performance during intense exercise that is carried out in one- to four-minute bouts (26).

Although more research is needed, there is evidence that beta-alanine can enhance muscle gain while you exercise (27).

HMB

Beta-hydroxy beta-methylbutyrate (HMB) is a molecule produced when the amino acid leucine is broken down in your body (28).

This molecule may help with recovery after intense exercise and reduce the breakdown of muscle proteins (29).

While mixed results have been reported, HMB supplements may improve muscle recovery and muscle gain, especially in those without previous training experience (29).

However, the studies showing the greatest benefits of HMB supplements have recently been questioned, and more information is needed to clarify their true effects (30, 31).

Summary There are several supplements that may improve weight and muscle gain over time by increasing the quantity or intensity of exercise performance. A few supplements with such possible benefits include caffeine, citrulline, beta-alanine and HMB.

Supplements that increase your calorie or protein intake could help you gain muscle when combined with an appropriate exercise program, typically weight training (2, 32).

Other supplements that improve your exercise performance can provide a larger stimulus to which your body must adapt. This could lead to better muscle or weight gain over time.

However, for most supplements there is little evidence to suggest that they can increase weight or muscle gain on their own.

BCAAs

There is no doubt that branched-chain amino acids (BCAAs) are critical for muscle growth (33, 34).

However, BCAAs are found in nearly all protein sources. Any time you eat protein, you are most likely already consuming BCAAs.

Additionally, research does not support the benefits of BCAA supplements for muscle gain (35, 36).

Despite their popularity, these supplements are unnecessary for muscle gain if you are consuming enough protein.

Testosterone Boosters

The hormone testosterone plays an important role in the anabolic processes of your body, which are responsible for muscle growth (37, 38).

Testosterone boosters make up a broad category of supplements that claim to increase this hormone and produce muscle gain.

Ingredients commonly found in these supplements include tribulus terrestris, fenugreek, D-aspartic acid, ashwagandha and DHEA.

Overall, most of these compounds are probably not beneficial for increasing testosterone or weight gain (39, 40, 41).

A small number of studies have shown possible benefits to some ingredients in these products, but more evidence is needed (42, 43).

Some of these supplements could be more effective in those with low testosterone. Regardless, testosterone boosters do not typically live up to their marketing claims.

CLA

Conjugated linoleic acid (CLA) refers to a specific group of fatty acids with possible health benefits (44).

Mixed results have been reported for the effects of CLA supplements on muscle gain. Some studies have shown small benefits, while others have not (45, 46, 47, 48).

Several studies have also shown that CLA may promote a small amount of fat loss, and it’s unlikely to cause a weight increase even if a small amount of muscle is gained (48).

Summary Many supplements claim to help you gain muscle or weight. However, most supplements are ineffective in that regard without proper nutrition and exercise. Overall, many supplements either produce minor or no benefits.

The most important lifestyle factors allowing you to gain weight and muscle are sufficient exercise and proper nutrition.

Specifically, you need to eat more calories than your body uses and eat more protein than your body breaks down.

Some dietary supplements can be convenient ways to help you consume more calories and protein, such as weight gainers and protein supplements.

Creatine is also a well-researched supplement that may help with weight gain.

Other supplements like caffeine, citrulline and beta-alanine may help you exercise harder, which could help provide a stronger stimulus to which your muscles need to adapt.

If you want to gain weight, be sure your exercise program and nutritional habits are in check. These will be the most critical factors for your success.