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Muscle Gain Potential Calculator

Most men can naturally gain 40 to 50 pounds of muscle in their lifetimes, and most women can naturally gain 20 to 25 pounds, but how much can you gain, exactly? Research shows that you can use the circumference of your wrists and ankles to predict how much muscle you can gain naturally in your lifetime. Enter your height, estimated body fat percentage, and wrist and ankle circumferences into the Legion Muscle Gain Potential Calculator to estimate how “jacked” you can get without taking steroids.

Frequently Asked Questions

How long will it take to reach my natural genetic potential for muscle gain?

It takes at least 4-to-5 years of proper dieting and training to approach your genetic potential for whole-body muscularity. After this point, further gains become vanishingly small.

How long it takes you to reach your genetic potential, though, depends on many factors.

First and foremost, the quality and consistency of your diet and training can accelerate or delay your progress. Many people spin their wheels with suboptimal training programs (or worse, just “exercise”) and make a number of mistakes in the kitchen (like not eating enough calories or protein), which prevent them from making progress as quickly as they should.

Thus, someone who’s been training and eating improperly for several years has the potential to make “year one” gains when he or she starts training and eating properly.

Furthermore, both age and starting condition reduce the potential for muscle gain. Older guys and gals will generally gain less than younger, and underweight people can gain a bit more than normal weight folks.

All in all, it’s fair to say that most people should be able to reach their genetic potential for muscle gain after about 4 to 5 years of proper dieting and training, although a more realistic target would be 5 to 10 years.

How long can I keep building muscle?

As a corollary to the last question, most people doing everything right in the gym and kitchen will keep gaining muscle for about 4 to 5 years, after which progress becomes painstakingly slow.

Now, there’s some debate among scientists as to whether muscle gain completely stops or becomes so miniscule that it’s almost impossible to measure, but the answer doesn’t really matter for our purposes. What’s important to understand is that no matter what anyone says, you can’t keep gaining a meaningful amount of muscle and strength indefinitely without taking steroids.

Remember this when people say their physique took “ten years of #dedication to build.” More like 4 to 5 years of proper dieting and training, followed by another half-decade of steroid use. This may sound harsh, but it’s true according to the scientific literature.

Also remember that most people—even the most knowledgeable and committed natural bodybuilders—aren’t doing everything “right” 24/7, 365 days per year. Instead, their diet and training plans get interrupted by holidays, trips, illnesses, personal and professional vagaries, waning motivation, and so forth. Thus, many people can continue gaining muscle and strength for a decade or more, albeit at a slower rate than they might achieve under perfect conditions.

What’s more, most people can continue making small gains in strength until age or injuries stymie their progress, mainly thanks to improvements in technique. For example, many veteran powerlifters can keep adding a few pounds to their one-rep maxes until their late thirties or forties.

You may also be able to keep gaining muscle up until this point, too, but we’re talking grams, not pounds.

How can you tell if someone is taking or has taken steroids?

In some cases, it’s easy to tell if someone’s on steroids.

If they’re an IFBB pro or look like one, for instance, they’re on the sauce.

It’s rarely that obvious, though. Most steroid users don’t look like professional bodybuilders or physique athletes. In fact, many look far more “normal” than you might think.

In these cases, the best way to determine whether or not someone is taking or has taken steroids is to calculate their fat-free mass index (FFMI), which is a measurement of how much muscle they have per unit of height.

It’s calculated by dividing your fat-free mass in kilograms by your height in meters squared, and you can calculate it by plugging your height, weight, and body fat percentage into the Legion FFMI Calculator.

I don’t like the results from this calculator. Is it possible that it’s wrong?

Maybe, but it’s more likely that you have unrealistic expectations of how much muscle you can build naturally.

You probably follow quite a few bodybuilders, fitness models, and “influencers” who put your potential for muscle gain to shame. And that’s okay. In fact, it’s good you’re coming to this realization now, before unrealistic hopes can sink their hooks in and set you up for major disappointment and failure later (or worse, drug use).

The good news, though, is no matter your genetic potential for muscle gain, you can build an outstanding physique. It doesn’t take stellar DNA to build a body you can be proud of.

If a guy new to weightlifting gains 30 to 40 pounds of muscle and stays around 10% body fat, he’ll look like a Greek god to most people. And if you’re a woman, you’ll likely love the way you look after adding just 10 to 15 pounds of muscle in the right places on your body and dieting your way down to about 20% body fat.

It may take longer than you’d like to get the body you really want, and you may never be as muscular or defined as your Instagram idols, but you absolutely can transform your physique into something special.

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