Insulin & Bodybuilding: Risks & Safety Information

Quick answer: Some bodybuilders take insulin because it's believed to speed up muscle recovery and boost nutrient uptake post-workout. But it's risky, off-label, and not medically recommended.

Pharmaceutical insulin is a hormone used to treat high blood sugar in people with diabetes. In this condition, the body either doesn't make enough insulin, makes none at all (type 1), or becomes resistant to it (type 2). Its main job is to move sugar from the blood into the cells, where it's used for energy or stored for later.

So what does insulin have to do with bodybuilding?

To push past natural limits, some high-level bodybuilders turn to extreme methods-including steroids and, surprisingly, insulin. Studies suggest that one in four steroid-using bodybuilders also takes insulin. Together, these substances are thought to speed up metabolism, enhance nutrient absorption, and promote muscle growth.

Scientifically, it makes sense. But using insulin for muscle gain is risky and not medically approved.

So, how does it affect muscle growth? And what are the side effects? Is using insulin for bodybuilding safe?

Let's take a closer look.

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Why do bodybuilders take insulin?

Bodybuilding is the practice of developing one's muscles through hypertrophic exercises, progressive resistance, and diet. It focuses on optimized muscle growth for aesthetic performances.

A big part of bodybuilding includes diet and supplements. While most bodybuilders stick to more or less natural supplements such as proteins, creatine, caffeine, glutamine, and others, high-level ones often turn to pharmaceutical products such as anabolic steroids, growth hormones, and insulin for extreme muscle growth. These help the muscles absorb more nutrients quicker after workout sessions.

🚨Warning: The use of insulin for bodybuilding is absolutely off-label. It's not recommended by healthcare providers and is not part of the list of official uses of this medication.

How does insulin affect muscle growth?

Besides its traditional blood sugar control use, insulin is an anabolic hormone known to support muscle growth.

While science backs up the fact that insulin promotes muscle growth, the way it works is still debated.

Here are the three main leads:

Insulin stimulates muscle protein synthesis and decreases muscle protein breakdown. Muscle protein synthesis is the process of building muscle mass from amino acids (the building blocks of proteins).
Insulin promotes carbohydrate storage in the muscle cells. After workouts, the muscles must be refueled with glycogen (the stored form of carbohydrates) to help with protein synthesis and mass building. Insulin increases nutrient storage and muscle replenishment after physical exercise by allowing more glucose, amino acids, and creatine to enter the muscles.
Insulin allows greater blood flow to the muscles. According to this study[2], "insulin decreases vascular resistance and increases organ blood flow, especially in skeletal muscle tissue, indicating that insulin is a vasodilator." An increased blood flow helps send more nutrients, glucose, and amino acids to the muscles, ultimately boosting muscle mass gain.

Is insulin a steroid?

Bodybuilders often have the misconception that insulin is a steroid.

But no, insulin is not a steroid.

Steroid hormones fall under the lipid category, while insulin is a peptide hormone formed from amino acids. However, it's believed that insulin works side by side with anabolic androgenic steroids and growth hormones to boost muscle growth.

Insulin and muscle growth: Is insulin an anabolic hormone?

Yes, insulin is a major anabolic hormone. Anabolic hormones, such as insulin, testosterone, growth hormones, and estrogen, promote muscle growth through anabolism when energy is used to construct complex molecules from smaller units.

The opposite process of catabolic hormones like cortisol, glucagon, or adrenaline inhibits muscle growth by breaking down molecules to use them for energy.

How do bodybuilders use insulin?

Because the use of insulin for muscle growth isn't legally or medically approved, it's not regulated. As a result, there's no official insulin protocol for bodybuilders. Instead, the practice is rather individual and based on a try-and-see approach.

Since insulin is not designed or approved for bodybuilding, there are no guidelines or guarantees of safety. What works for one person could be harmful, or even fatal, for another. This makes experimenting with insulin an extremely high-risk and unpredictable strategy for muscle growth.

⚠️ Again, we want to strongly emphasize that using insulin for muscle growth is not medically approved or recommended, as it carries serious health risks.

While some bodybuilders may see insulin as a shortcut to rapid gains, this approach often overlooks the complexity and danger of using a powerful hormone without medical supervision.

Unlike protein powders or legal supplements, insulin affects critical bodily functions like blood sugar regulation. A single misstep in timing, dosage, or carbohydrate intake can have severe consequences.

Do they use insulin before or after bodybuilding workouts

The main reason bodybuilders take insulin is to boost muscle mass by speeding up post-workout recovery. Typically, they inject a fast-acting (bolus) insulin within 15 minutes after training, alongside carbohydrates, to quickly refuel muscles and enter an anabolic state

Insulin/carbohydrate ratio

Insulin use for muscle growth is only effective if combined with carbohydrate intake.

Taking insulin without ingesting carbohydrates causes low blood sugar (hypoglycemia) that can lead to dangerous complications, including seizures, coma, and death.

A general rule is to consume at least 15 grams of carbohydrates for every unit of insulin you inject.

⚠️ While we do not recommend using insulin for bodybuilding purposes, if you decide to do this, you should use a glucose meter to track your blood sugar levels within the next 4 hours after an injection.

Side effects of using insulin for bodybuilding

The use of insulin for muscle growth is unsafe.

The risks and side effects may greatly outweigh the benefits, and several bodybuilders have died from insulin abuse and misuse.

The main risk associated with insulin abuse for bodybuilding purposes is hypoglycemia (low blood sugar).

While insulin is a hypoglycemic hormone medically used to lower blood sugar levels in diabetic patients, when you inject a dose of insulin that's not adapted to your carbohydrate intake (too much insulin) or level of physical activity, you're at high risk of a blood sugar drop.

Symptoms of hypoglycemia include:

Drowsiness
Fast heartbeat
Fatigue
Hunger
Sweating
Irritability
Paleness
Shakiness
Dizziness

While most of the time, eating or drinking fast-acting sugars (sugar, juices) quickly gets your blood glucose back to normal range, you may not be able to recover by yourself if you've injected a high dose of insulin.

Severe cases of hypoglycemia require immediate medical attention and can sometimes lead to confusion, seizures, coma, and even death.

Country Regulations and Bodybuilding Federations

Depending on your country, insulin may or may not be regulated.

Some places allow over-the-counter sales, while others prohibit insulin use outside of a diabetes diagnosis.

Additionally, many bodybuilding federations consider insulin a banned substance. For instance, the International Olympic Committee bans the use of insulin unless medically necessary for athletes with diabetes.

Insulin and bodybuilding: Is it worth the risk?

Insulin may indeed be a powerful anabolic hormone that influences muscle recovery and growth by increasing nutrient uptake and promoting protein synthesis.

However, using it for bodybuilding is not recommended. The risks, especially life-threatening hypoglycemia, which can lead to seizures, coma, or death, far outweigh any potential muscle-building benefits.

Unlike regulated performance enhancers or supplements, insulin use in bodybuilding is entirely off-label, lacks standardized dosing protocols, and is often done without medical guidance, making it extremely dangerous.

So, is it worth the risk?

We say no!

While some advanced bodybuilders may see short-term gains, the long-term consequences can be devastating. There are safer, more sustainable ways to support muscle growth.

Always consult with a healthcare provider before considering any pharmaceutical substance for non-medical or performance purposes.

Your health is not worth gambling for aesthetics.

Key Take Aways:

Here's a quick recap of what we discussed in this article:

💪 Insulin is anabolic: It promotes muscle growth by enhancing nutrient delivery and protein synthesis, but it's not designed for bodybuilding use.

⚠️ It's off-label and risky: Using insulin without medical need can cause life-threatening hypoglycemia, especially if not paired with carbs.

🧪 No standard protocol: There's no medically approved way to use insulin for muscle gain-bodybuilders rely on trial and error.

🚫 Not worth the risk: Gains are possible, but consequences can be severe. Safer alternatives exist for building muscle.

We'd Love to Hear From You!

💬 Have questions about insulin and bodybuilding? We'd love to hear from you and keep the conversation going in the comments section below. Let's help keep each other safe!

📆 Article Update History:

✅ Updated: April 23, 2025

Originally Published: December 30, 2022

December 30, 2022

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The information presented in this article and its comment section is for informational purposes only and is not intended as a replacement for professional medical advice. Always consult with a qualified healthcare provider for any medical concerns or questions you may have.

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