Yes — weight lifting increases testosterone. But the more important question is whether that increase actually leads to more muscle growth, and the answer to that is considerably more complicated.
Weight lifting produces a temporary spike in testosterone levels during and immediately after training. Studies on squats show free testosterone — the biologically active form — increasing anywhere from 40 to 55% above baseline immediately post-workout, with levels returning to baseline within 60–90 minutes. The spike is real. Whether it drives meaningful additional muscle growth is where the science gets interesting.
Read on, because knowing the answer to this question can help you get rid of ineffective practices that waste your time and energy, and inspire you to focus on what’s really crucial for achieving your physique goals.
Hormone Obsession vs. What Actually Builds Muscle
Strength training does more than just create muscle damage — it also stimulates the release of a variety of hormones that have a big impact on the rate of recovery and muscle growth. And according to modern bodybuilder wisdom, designing your program in a way that maximizes anabolic hormone production will help you get bigger, stronger and leaner in less time.
In fact, hormone management has become a vital part of muscle building and there are a ton of guys who spend all their time on finding ways to boost their T levels instead of focusing on, let’s say, lifting heavy stuff more often.
Online bodybuilding gurus constantly advocate specific methods for structuring your training to get the most out of your hormonal environment and diet programs seem to emphasize the influence of certain foods and meal timing on hormone activity more than ever.
But does obsessing about your hormones really lead to substantially better gains?
In our search for solid proof, we consulted the science and found that the data from most studies actually raises more doubts than it provides evidence in support of this hype.
Truth be told, the only thing that has been repeatedly shown to build muscle size and strength is muscle overload, while everything else seems to be — more or less — based on speculations and partial evidence.
Which leads us to the following question: do anabolic hormones derived from exercise affect muscle building in a significant way, or have we all been buying into myths?
Hormones 101
Here’s how it works. Hormones are the chemical messengers that make up our body’s communication system, where every different hormone represents a specific message or instruction that needs to travel throughout the body to reach its destination and influence the function of an organ.
By enabling communication between distant parts of the body, they coordinate complex and vital bodily processes like growth, metabolism, fertility, immune responses and even behavior.
In response to a signal from the brain, hormones are secreted directly into the blood by the glands in the endocrine system responsible for producing and storing them.
Once they’ve entered the bloodstream, hormones travel throughout the body looking for specific receptors to which they can bind. In other words, although all cells are exposed to hormones, not all of them react — only the target cells, which have receptors (think of them as antennas) for that hormone will respond to its signal.
The hormone then binds to its receptor and creates an adequate biological response within the cell, and effectively the body as a whole. So you can think of hormones as managers telling an employee what to do.
How Weight Lifting Changes Your Hormonal Environment
Right after you begin your first set, a complex variety of hormones get to work to create an adequate response to the physical activity and coordinate the repair process across multiple tissues.
We’ll skip epinephrine, norepinephrine, vasopressin, aldosterone and cortisol — all of which have important roles during exercise — to focus on the holy grails of muscle building: testosterone and growth hormone.
Growth hormone is a chain-structured group of 191 amino acids released by the pituitary gland, with the task of stimulating growth in all tissues of the body. More specifically, it increases protein synthesis and cell transport, regulates metabolism and remodels bone and collagen tissues. Production increases during exercise, where it plays a critical role in repairing muscle tissue and producing hypertrophy and strength gains.
Testosterone is released by the adrenal glands during heavy strength and weight training. Its job is to promote protein synthesis, support production of new red blood cells — which increase the body’s ability to use oxygen more effectively — and serve as one of the main hormonal communicators of the muscle tissue repair process. In other words, elevated testosterone helps you perform better during strenuous exercise and causes bigger gains, which is why athletes love it so much.
An influential 21-week study by Ahtiainen J.P. et al. showed a correlation between T levels and changes in isometric strength and muscle size, meaning that both basal testosterone concentrations and training-induced acute testosterone responses are strongly associated with muscle and strength gains.
Which Types of Weight Training Produce the Most Testosterone?
Not all weight training produces the same hormonal response. Here’s what the research shows:
Compound movements beat isolation exercises every time. Squats, deadlifts, bench press and rows produce significantly higher testosterone responses than isolation exercises like bicep curls or leg extensions. The reason is simple — the more total muscle mass recruited in a single movement, the greater the endocrine system response. A bicep curl works one small muscle. A squat works the quads, hamstrings, glutes, lower back and core simultaneously.
Free weights beat machines. Research consistently shows that free-weight exercises trigger stronger hormonal responses than machine-based equivalents. A barbell squat produces a greater testosterone spike than a leg press, likely due to the greater CNS demand and stabilization requirements of the free-weight version.
Volume and intensity both matter. Protocols using moderate to high intensity (70–85% of your one-rep max) with higher volume (3–5 sets of 10–15 reps) and shorter rest periods (60–90 seconds between sets) produce the largest testosterone spikes. Six sets of 10 squats at moderate weight have been shown to significantly elevate post-exercise testosterone. Interestingly, going too heavy — like competitive powerlifters grinding at 90% of their max — doesn’t always produce the same hormonal response as high-volume moderate-intensity work.
Leg training produces the biggest response. The legs account for more than 60% of the body’s total musculature. Training them hard produces one of the largest acute testosterone spikes of any session you can do. This is why skipping leg day isn’t just an aesthetic mistake — it’s a hormonal one too.
Does the Testosterone Spike Actually Build More Muscle?
This is where it gets interesting — and where a lot of popular wisdom falls apart.
One big study by West et al. provides a compelling answer. The researchers wanted to know if increased testosterone production from leg exercises would cause an increase in muscle gains, so they made 12 healthy young men train their biceps for 15 weeks on separate days and under different hormonal conditions.
To stimulate low testosterone conditions, subjects performed only arm curls. To achieve high testosterone conditions, they performed arm curls followed immediately by a high volume of leg exercises (5×10 of leg presses and 3×12 of leg extension/leg curl supersets).
The most interesting part: each subject also served as his own control by exercising one arm under high testosterone conditions and the other arm on a separate day under low testosterone conditions.
The reasoning was that if exercise-induced increases in testosterone really lead to bigger muscle gains, there should be a measurable difference in the size gained in each arm — in favor of the arm trained under high testosterone conditions.
But the results showed that although strength and muscle size increased in both arms, the increase wasn’t bigger in the arm trained under high testosterone conditions.
However, another study conducted by Ronnestad B.R. et al. had the opposite outcome. In this study, subjects performed the high-volume leg exercises first and the arm exercises second — and the result was a greater hypertrophy response in the biceps.
Could the order of exercises be the key to promoting bigger lean gains through exercise-derived testosterone? We can’t say for sure. You’ve probably realized by now that science is complicated and messy and can rarely provide straight-forward answers, so let’s avoid getting our hopes too high.
That’s what Phillips et al. thought when they decided to investigate a bit deeper into the same data collected by Ronnestad and found no significant changes in arm size. But to make matters even more bizarre, West et al. then looked at Phillips’ data from another perspective and claimed that the increases in lean body mass originally reported by Ronnestad were real — but weren’t caused by testosterone at all. Instead, they were directly associated with changes in cortisol, the much-hated stress hormone.
What Does All of This Mean?
To summarize scientific efforts in this field: it’s true that heavy compound movements like squats, leg presses and deadlifts cause greater release of anabolic hormones including testosterone than isolation exercises. But it’s highly unlikely that these acute and transient increases in T levels lead to greater lean mass gains.
In fact, there is no sound scientific proof of such a relation and its popularity seems to stem from anecdotal evidence and the willingness of people to worship any method claimed to accelerate muscle building. Compound exercises increase muscle size and strength due to local hormonal factors released at the site of most tension — factors that have little to do with overall circulating T levels.
So we’re sorry to inform you that designing your program specifically to optimize acute hormone release is pretty much a waste of your precious time.
But you shouldn’t worry about that, because there is one sure-fire thing you can do to promote massive muscle gains: increase local muscle overload.
What You Should Do Instead
Bodybuilding fads come and go, but what remains fixed is the ability of muscle overload to cause lean mass gains. Muscle overload can be increased in three main ways:
Add weight. By increasing the weight you work with, you increase exercise intensity and provide more overload to your muscles. More overload causes more muscle damage, which means more growth — given that your diet meets the nutritional demands of your training.
Add volume. Weight is only one dimension of training volume, defined as weight × sets × reps. Another way to increase volume is by adding extra sets with your current weight or increasing reps. The bigger the amount of work your muscles are forced to do, the greater the hypertrophy.
Improve density. Density represents volume over time. If it now takes you 15 minutes to do 4 sets of 10 reps with 250 pounds, but you can pull off the same volume in 10 minutes after two weeks of training, your density has improved and you’ll reap more gains from the same workout.
A Simple Program Built on Muscle Overload
Forget hormone optimization. Here’s what a program built around progressive overload actually looks like:
Day 1 — Lower Body
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Barbell Squat | 5 | 5–8 | 2–3 min |
| Romanian Deadlift | 4 | 8–10 | 90 sec |
| Leg Press | 3 | 10–12 | 90 sec |
| Walking Lunges | 3 | 12 per leg | 60 sec |
Day 2 — Upper Body
| Exercise | Sets | Reps | Rest |
|---|---|---|---|
| Barbell Bench Press | 5 | 5–8 | 2–3 min |
| Barbell Row | 4 | 6–8 | 2 min |
| Overhead Press | 3 | 8–10 | 90 sec |
| Weighted Dips | 3 | 8–10 | 90 sec |
Add weight when you hit the top of the rep range with good form. Add a set when the weight jumps significantly. That’s progressive overload. That’s what actually builds muscle.
For more on what genuinely moves the needle hormonally, check out my guides on natural testosterone boosters and do leg workouts increase testosterone.
Conclusion
Focus on gradually increasing muscle overload in each successive workout and you’ll get the results you dream of. Focus on maximizing hormonal production and you’ll be stuck with average-looking muscles, reading articles on improving T levels forever.
Good luck and stay tight.
