8 Reasons why you have big triceps and small biceps
Genetics
Genetics play a major role in why some people have larger triceps and smaller biceps. Individuals who possess more fast-twitch muscle fibers in their triceps are predisposed to developing bigger and stronger muscles due to the explosive movements these fibers allow for, such as weightlifting or sprinting.
On the other hand, those with more slow-twitch muscle fibers tend to have less overall muscle mass because these fibers are geared towards endurance activities.
No matter what your genetics may be, it is possible to build bigger muscles. With a well-planned exercise and nutrition routine, you can increase the size of any muscle group no matter what genetic makeup you have. With commitment and determination, anyone can reach their goals for their dream physique.
How to fix the genetics problem
If you have big triceps and small biceps due to genetics, then the best way to fix the imbalance is through targeted training. This means doing exercises that specifically target your biceps, such as curls or chin-ups.
By consistently working your biceps, you can eventually overcome your genetic predisposition and develop equally-sized muscles.
Poor exercise selection

People can often have large triceps and small biceps due to improper exercise selection. This is typically caused by selecting exercises that heavily target the triceps, such as skull crushers, or omitting exercises that work the biceps altogether, like bench presses. This lack of attention to the biceps results in disproportionate muscle development between the two areas.
You have to take volume, intensity & frequency in consideration when selecting your exercises. If you want to build bigger biceps, then you need to be doing exercises that place a high level of stress on the muscle (i.e. heavy curls), and you need to be doing them frequently (i.e. 3-4 times per week).
Also you have to consider how much reps and sets you do while doing the exercise. This has to line up with the triceps exercises.
By performing chest exercises, such as the bench press, you are not only strengthening your chest muscles but also engaging your triceps. This can lead to an increase in the total workout volume of your triceps which can make it more challenging to build bigger biceps if you don’t take this into consideration.
Similarly, back exercises that involve contracting the bicep muscles add up to its total workout volume and should be included in a regular training routine for optimal growth; however, if these back exercises are neglected then your biceps will not be able to reach their full potential compared to that of the triceps.
How to fix the exercise selection problem
If you have an imbalance between your triceps and biceps due to incorrect exercise selection, then the best way to fix it is by including more exercises that target the biceps.
This could include curls, chin-ups, and rows with heavy weights and high reps in order to ensure optimal muscle growth.
Doing this will help build up your biceps while also improving the overall symmetry of your arms.
Over training the triceps

People often end up with big triceps and small biceps because they are not training their muscles in a balanced way. This is usually due to overtraining the triceps, which occurs when people dedicate too much time and energy to this muscle group by doing excessive exercises, sets, and reps for it.
Over training the triceps can cause two issues: (1) it can restrict the amount of blood and nutrients that reach to the biceps, preventing them from growing optimally; and (2) it can cause a prolonged state of inflammation, which can damage crucial muscle fibers and increase one’s risk for injury significantly.
How to fix the over training problem
If you have developed an imbalance in your upper arm muscles due to over training, with larger triceps and smaller biceps, the best way to correct this is by decreasing the amount of training you do for your triceps.
This involves reducing the number of exercises, sets and reps that you complete for this muscle group.
To restore balance in your arms, it is important to give more attention to your biceps by performing additional exercises, sets and reps specifically targeting this muscle group.
Inadequate recovery

One of the main reasons why people may have large triceps and underdeveloped biceps is due to inadequate recovery from their workouts. If an individual trains too often or performs excessive amounts of volume, they are not allowing their muscles sufficient time to recover between sessions.
Without proper rest, the muscles cannot repair themselves and build strength, resulting in smaller and weaker biceps compared to larger triceps.
How to fix the recovery problem
If you have big triceps and small biceps due to inadequate recovery, then the best way to fix the imbalance is by giving your muscles more time to recover. This means reducing the frequency and/or volume of your workouts. You should also focus on getting enough sleep and eating a nutritious diet to support muscle growth.
Poor diet and nutrition

A balanced diet is essential for individuals who are attempting to achieve larger triceps and smaller biceps. Without the right combination of nutrients, including proteins, carbohydrates, fats, vitamins and minerals, it will be difficult to build muscle mass in any part of the body.
People who are trying to lose weight or gain muscle should pay special attention to their diets in order to ensure they’re getting enough calories and nutrients necessary for growth and repair of their muscles.
Without a proper diet that supplies the body with adequate nutrition, it can be nearly impossible for an individual to reach their goals when it comes to increasing triceps size while decreasing bicep size.
How to fix the diet and nutrition problem
If you have an imbalance in your upper body musculature, with disproportionately large triceps and small biceps due to an inadequate diet and nutrition, the best way to correct this is by focusing on eating a healthy and balanced diet. This should include adequate amounts of protein, carbohydrates, and healthy fats that will provide your body with the essential nutrients it needs. Additionally, make sure that you are consuming enough calories so that you can reach your desired outcome.
Incorrect exercise technique

The last and arguably most critical factor for why your triceps are bigger than your biceps is due to incorrect exercise technique. This can be attributed to utilizing too much weight or not properly following the instructions of an exercise, both of which can lead to an imbalance between the muscles as well as a higher risk of potential injuries.
How to fix the exercise technique problem
If you have disproportionately large triceps compared to your biceps due to incorrect exercise technique, the best way to address this imbalance is by ensuring that you use proper form and technique when performing exercises. This means using a lighter weight than usual and concentrating on executing each repetition with perfect form. Additionally, it is beneficial to focus on exercises that target the biceps more specifically in order to bring them up to size with the triceps.
Bonus – Biceps are generally smaller than triceps

The biceps are generally smaller than the triceps because they are a smaller muscle group and are not used as often in daily activities. This can lead to people not giving them enough attention during their workouts, which may cause muscular imbalances. Without proper care, the biceps may not reach their full potential size-wise when compared to the triceps.
If you have disproportionately large triceps compared to your biceps due to incorrect exercise technique, the best way to address this imbalance is by ensuring that you use proper form and technique when performing exercises.
This means using a lighter weight than usual and concentrating on executing each repetition with perfect form. Additionally, it is beneficial to focus on exercises that target the biceps more specifically in order to bring them up to size with the triceps.
The triceps muscle, which makes up roughly two-thirds of the upper arm, is composed of three heads: the lateral head, the medial head, and the long head. The biceps muscle also has two heads: the short head and the long head; however it only comprises about one-third of your upper arm.
Therefore, to ensure a well-rounded physique it is important to incorporate exercises that target both muscles groups into your workout routine.
Conclusion on big triceps and small biceps
The primary explanation for why some individuals have large triceps and diminutive biceps is due to genetics, insufficient rest, an unhealthy diet and nutrition plan, incorrect exercise technique, and the fact that biceps are typically smaller than triceps.
If you possess this dis proportionality then the best way to remedy it is by focusing on your bicep muscles more in your workouts as well as eating a nutritious diet.