Testosterone 101

In the health and fitness industry, this hormone has a huge rep. So big that there are both legal and illegal, safe and unsafe, products on the market that claim to raise your testosterone. We’re talking testosterone boosters. We’re talking herbs. We’re talking vitamins. We’re talking the king HRT. The amount of products claiming to raise your testosterone by 50% or something along those lines, is just astounding. But do they work? And if they do, how much? What is truly the best way to raise your testosterone while also avoiding some serious adverse effects and still maintaining and even improving your longevity? We are going to cover all that and more in this post on testosterone.

To start this off we are gonna quickly talk about the physiology of testosterone to help us better understand the rest of our more practical discussion. Testosterone is a steroid hormone part of a group known as androgens, which are 6 naturally produced molecules in the body of different potency which are responsible for masculinization or for “male” characteristics. For our training purposes, we focus on testosterone specifically as it has the most interaction with muscular tissue with other androgens interacting more with sex-linked tissues. Testosterone is largely controlled by the hypothalamic pituitary gonadal axis. All of this will come back to be important later in our discussion and very simply put, the hypothalamus is a structure in your brain that secretes a hormone called GnRH (Gonadotropic Releasing Hormone). GnRH then stimulates the pituitary (another structure in the brain) to secrete Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). This so far is the same process in both males and females. Now in males LH then goes to the testes to stimulate the production of testosterone while in females, LH goes to the ovaries to stimulate the production of testosterone. Obviously males have a higher testosterone level than females (about 15-20x higher) and in females much of the ovarian testosterone is eventually converted to estrogen either in the ovaries or in fat cells by something called an aromatase enzyme. Because of this a higher percentage of testosterone and its derivatives in females comes from the adrenal gland – a gland that sits on top of your kidneys – and is regulated by different hormones. Males also have adrenal glands that produce testosterone, but the large majority of male testosterone comes from the testes.

An important piece of this discussion is something known as negative feedback. All that means is essentially that when your testosterone levels become high, they will then signal the hypothalamus and pituitary to stop secreting GnRH and LH so that the testosterone downstream will no longer be formed. It’s somewhat of a safety mechanism to limit excessive testosterone production.

So now that we have testosterone produced, what is it actually going to do in the body? After it is produced, it circulates throughout the bloodstream until arriving at its target tissues where it enters cells and binds to its target receptor to initiate downstream effects at the cellular level. These effects vary based on the tissue. As I just mentioned, testosterone is obviously going to be important for development of male sexual development as well as for secondary sex characteristics such as facial hair and body hair growth and is also important for libido and can cause further behavioral changes such as aggression due to effects on the Central Nervous System, or the brain. Testosterone is also a precursor for estrogen which is extremely important for bone health. When acting in muscular tissue, testosterone increases protein synthesis and inhibits protein breakdown. This is why it is known as an “anabolic” hormone. Anabolic meaning growth and building versus a catabolic hormone which results in breaking down. Simply put, because muscle is formed from protein, testosterone results in increased muscle mass and cross-sectional area. Then downstream of this, because force production is directly related to cross-sectional area, testosterone increases long-term strength by increasing muscle cross-sectional area. Finally, testosterone also has effects on fat tissue, by limiting the storage of lipids within fat cells. In other words, testosterone plays a role in decreased fat accumulation.

Alright, that is your testosterone science 101, just the basics that will help us better understand its function for our purposes of training and living optimally. With these benefits of bone health, decreased fat accumulation, increased muscle mass – it’s probably pretty obvious why so many companies have created products to attempt to raise testosterone. But what can we do to increase it to a healthy level? And emphasis here on healthy level. One way to increase your testosterone or androgen levels is certainly by taking exogenous anabolic steroids such as testosterone replacement therapy (TRT, HRT), or other androgenic compounds such as trenbolone, oxandrolone, etc. And yes, it will give you all the benefits we just talked about, but it will also bring about many downsides. Unless prescribed by a doctor for patients with low endogenous testosterone levels in the case of HRT, these are typically illegal for human use and for good reason. The amount of adverse effects is honestly too much to list but include possible severe liver damage, high blood pressure, high cholesterol, hypercoagulable states (or increased blood clotting) which can lead to heart attacks and strokes. In other words, use of exogenous androgens can either lead to sudden death or can severely lower your longevity by increasing known physiologic markers that are risk factors for mortality in the long term. What’s more it can also cause infertility and testicular atrophy due to the negative feedback mechanism we spoke about earlier. When you have extremely high androgen levels from taking it exogenously, you are signaling to your hypothalamus and pituitary that you don’t need any more. Then these structures stop producing GnRH and LH/FSH to stop testosterone production; however, the problem with this is that these molecules also are responsible for the production of sperm and for testicular development. In other words, with decreased LH/FSH production, we also get decreased testicular tissue and sperm production. With all these side effects, it is simply just not worth taking exogenous steroids. Especially if you prescribe to my philosophy on training and life. Do I want you to achieve your goals of increasing muscle mass and decreasing fat to have a physique you are proud of? Yes, of course. But even more importantly, I want you to train in order to achieve your Quan – which is the entire package. The joy, the love, the optimal health and well-being. Not only have exogenous anabolic steroids been scientifically proven to decrease your longevity and optimal health as I just mentioned, but they do not promote achieving a physique in a way that is congruent with also achieving your Quan. This is done by training for a physique in a sustainable way in which you learn to enjoy the process more than just the final goal. Someone who is only focused on the goal of a good physique yet hates the process will have an infinitely harder time achieving and maintaining that physique as well as maintaining the process that comes with it. Furthermore, the incidence of body dysmorphia amongst exogenous steroid users only focused on the goal of a final physique is also significantly higher than those who are training without exogenous steroid use and training not only for the goal of a good physique but also for overall physical and mental health and wellbeing.

So enough on that soapbox and back to increasing testosterone levels to a healthy level. And the good news is that you are not going to increase your testosterone levels to an unhealthy level by any training or lifestyle method, or any legal product on the market. So we can go all out on these methods that we are about to talk about to increase testosterone as much as possible in this natural manner. And aside from our benefits of increased muscle mass and fat loss, higher endogenous testosterone levels are associated with decreased risk for chronic disease and all-cause mortality. So this truly is an important hormone to optimize.

First let’s talk about methods that are the king in the market of increasing testosterone. Use these methods and you are 95-99% of the way there as far as legally and safely increasing your testosterone is concerned. These methods can be broken down into strategies with 1) training principles, 2) rest and recovery, 3) sleep, and 4) diet and nutrition. The more you listen to this podcast you will find this to be a recurring theme. Achieving optimal human functioning almost entirely comes from optimal functioning in these tenants. The novel gadgets and supplements may or may not provide any benefit, but even assuming they do – they only are going to help you get that final 1-5% of your results. So you can see how it is often difficult to watch people focusing so much on the 1-5% (aka the cryotherapy, the pneumatic massagers, the testosterone boosters) while they essentially neglect the 95-99% which can be obtained through simple methods in the tenants I just described. It really is analogous to re-arranging the deck chairs on the titanic. So back to increasing testosterone, let’s start with the 95-99%:

First, lets talk about training principles that have been scientifically proven to increase testosterone levels and therefore increase muscle mass and decrease fat mass. When designing a resistance or weight-lifting program there are many variables to take into account. What type of exercises, how heavy you should be lifting, how many sets, how many reps, how long the rest periods should be, etc. Many of these variables have had scientific, peer-reviewed studies completed that demonstrate how to optimize the specific variable for the highest testosterone production.

Testosterone is increased most through completing exercises that involve large muscle groups. For example, testosterone will be increased much more through completing a deadlift, back squat, or power clean (which all involve the many large muscles in the legs and spine), compared to the smaller testosterone increase that would be achieved through completing bicep curls, calf raises, or tricep pushdowns.

In general, heavier weight results in increased testosterone production. Specifically, the load is optimized for testosterone production when using a weight that is 85-95% of your 1 repetition maximum for that exercise. For instance, if you can perform a back squat with 300 lbs for 1 rep, then you want to be performing back squats with 255-285 lbs if you want to maximize testosterone production. Performing in this weight range means that you should be able to perform about 2-6 reps of the exercise. So in our example you could perform 6 reps of 255lbs and really be maximizing your testosterone.

With training, volume for an exercise is often defined as the amount of weight times the amount of repetitions times the amount of sets. And then the volume for all exercises is summed to determine the total volume of the workout. For increasing testosterone, you want to be training at moderate to high volumes. This means training with multiple sets of each exercise (about 3-6 sets of each exercise) and multiple exercises with the exact number of exercises depending on many other factors.

Rest periods are defined as the amount of time spent between each set. To optimize testosterone production, you really want short rest periods. Specifically, you should be resting about 30-60 seconds in between sets.

In sum, to increase your testosterone through resistance training, it is optimal to perform lifts that involve large muscle groups, with 85-95% of your 1 rep maximum, for 3-6 sets per exercise, and a rest period of 30-60 seconds. Obviously, there are many other factors that go into forming a good physique and gaining strength other than just testosterone levels; thus, creating a truly optimal program is not as simple as just following these rules. That being said, due to the importance of testosterone, I do incorporate many of these principles when designing programs for my clients. For example, specifically for the client who wants to focus on muscular hypertrophy and fat loss, I will program 2 large muscle group exercises per workout (i.e. back squat and deadlift) for 5 sets each starting at 85% of their 1RM for 6 reps with rest periods between 60-90 seconds.

Next up is rest and recover. And as always with training, one of the most important factors is your rest and recovery when you are not training. Overtraining Syndrome is a phenomenon that is caused by excessive training without proper recovery time and can result in severe maladaptation in physiology and performance. And testosterone is not immune to this effect. Specifically, overtraining due to excessive volume (i.e., training too many days without a rest day, or performing too many sets and reps in many consecutive training sessions) has been demonstrated to severely decrease testosterone levels. Essentially, when your body is not allowed proper time to recover, its energy stores will be depleted, and not enough energy will be available for non-essential functions such as increased testosterone production. How much time is needed for recovery is extremely variable depending on the individual; thus, I cannot give a simple rule like I was able to for the training variables that we just talked about. That being said, a good rule of thumb is that beginners should be training no more than 2-3 times per week, intermediates 3-4, and advanced 5-7. It really is important to listen to your body and take rest days when needed. And also when programing and making a training schedule, it is important to allow body parts time to recover. For instance, allowing your chest to rest at least 48 hours before attempting more chest exercises. Rest and recovery can be multiple episodes in and of itself, so I will leave it at that right now with the simple fact that in order to optimize testosterone production, you have to prioritize your recovery, whatever that means for your individual situation.

Next is sleep. And the importance of sleep will also end up being a recurring theme on this podcast, and testosterone optimization is no exception when it comes to its importance. There was a study done at the University of Chicago which demonstrated that restricting sleep to 5 hours per night for only 1 week in young healthy males, resulted in a 10-15% decrease in daytime testosterone levels. Thus, getting a solid 7-8 hours of sleep a night and all the habits that are necessary to achieve this, are very important for optimizing testosterone levels. Similarly to rest and recovery, sleep habits are too extensive to go into within this episode, but for right now, just know that you must be getting adequate sleep each night if you are going to increase your testosterone.

The last pillar of increasing testosterone that we will talk about here is diet and nutrition. One thing to be careful about here is claims about how there are “super foods” that are going to magically increase your testosterone. There are some that claim foods such as ginger will increase your testosterone, but a careful analysis of such studies demonstrates that these experiments were completed on infertile men, or those with very low baseline testosterone. If you fall into that category, then ginger may increase your testosterone. However, even more important for increasing testosterone through your diet, is a more holistic look at dietary practices. Much like how poor sleep habits can decrease your testosterone, poor overall diet habits can also do the same. A 2018 peer-reviewed study of 125 adult males demonstrated that diets with high amounts of bread, pastries, deserts, dairy, and restaurant foods were associated with lower testosterone levels while diets with high amounts of homemade foods and dark green vegetables were associated with higher testosterone levels. In sum, pro-inflammatory foods such as refined sugars and highly-processed foods can limit testosterone production, especially compared to diets high in natural, plant-based foods.

With this mention of plant-based foods we should also take the time to debunk the myth of soy intake decreasing testosterone and increasing estrogen. For those less aware of plant-based protein options – soy is the most widely used source of protein for those of us that are plant-based. While there may have been older studies making the claim that soy intake results in high estrogen and low testosterone, recent studies have demonstrated this to not be the case. In fact, a 2021 meta-analysis by Reed and colleagues analyzed 38 clinical trials that looked at this claim and demonstrated that soy intake had no effect on either testosterone or estrogen levels. So rest-assured my plant-based friends, you can still achieve optimal testosterone levels without ever eating an animal product.

Another diet/nutrition variable that must be considered when thinking about optimizing your testosterone levels is the amount of overall calories that you are consuming in a day. If you have a normal BMI and severely restrict calories, then your testosterone production will take a hit. It is important to note 2 key facts about that statement I just made. First, a decrease in testosterone is seen in those with normal BMIs who severely restrict their calories. When you look at most of these studies that are measuring testosterone levels in relation to calorie restriction, they are defining a calorie restricted diet as 1,500 to 1,800 kcals per day for adult males. For reference, a 180 lb athlete who performs light physical activity, should consume about 3000 kcals per day to maintain weight. Thus, we are talking about over a 1,000 kcal deficit per day, which is quite excessive. In practice, it is recommended that a 500 kcal/day deficit be maintained in order to lose weight in a sustainable fashion (amounts to about 1 lb per week). It is likely that maintaining this more reasonable deficit has less of an effect on testosterone levels. And then the second key fact about the original statement is that a decrease in testosterone is seen in those with a normal BMI who severely restrict calories. In overweight or obese individuals, a severe calorie deficit actually results in an increase in testosterone levels. This makes sense when we think back on the fact I briefly mentioned previously that testosterone can be converted to estrogen in fat cells by aromatase enzymes. Thus, with more fat cells, there is more aromatase to convert testosterone to estrogen, resulting in lower serum testosterone levels. For this reason, a calorie deficit is going to be beneficial for testosterone levels in the obese individual partly because of the high amount of fat that will be lost which will decrease the amount of testosterone that is converted to estrogen.

These points we just talked about regarding calorie restriction also apply to your body composition on a more chronic level. That is to say that as your body fat percentage decreases, your testosterone will generally increase. However, again to similar to what we just talked about; this relationship only holds true to a certain point. When your body fat percentage gets below 10-12%, you are going to start to see a decrease in your testosterone levels. This has been demonstrated in peer-reviewed studies with natural body builders during their competition prep in which they will drop from about 15% body fat to near 5%. In one particular case study, this drop in body fat corresponded to over a 4-fold decrease in total testosterone levels! So with this knowledge, if you were looking to perfectly optimize your testosterone levels, you would maintain your body fat around the 10-12% mark. That being said, maintaining 10-12% body fat is no easy feat especially for those that are not genetically inclined to be lean. So really the main takeaway here is that if you are simply able to achieve a normal BMI or a body fat percentage between 10-18%, you will really be doing yourself favors as far as testosterone optimization is concerned.

The last point we’ll talk about here in relation to increasing your testosterone through diet is fat intake. Really what the main takeaway is going to be here is do not falsely try to limit your fat intake. Fat often gets a bed rep in the nutrition department and really for no good reason. Nutrition and meal plans are very complex and have to take into account many variables; however, the big points are this. Based on your goals you will have a certain amount of g/kg of protein needed, a certain amount of g/kg of carbs needed, and a certain amount of total overall calories. After the calories from your carbs and your protein are accounted for, you will have a certain amount of calories left over. These calories, which generally amount to at least 30% of your total calories, should then be given to your dietary fat intake. And if you stick with that, you will be optimizing your testosterone production as far as dietary fat intake is concerned. But where you are going to run into problems is when you listen to that bad rep that fat gets and try to overemphasize protein at the expense of having enough fat in your diet. A 2021 meta-analysis by Whittaker and Wu demonstrated that a low-fat diet (~20% of total calories coming from fat) was associated with a 10-15% decrease in total testosterone compared to a high-fat diet (~40% of total calories coming from fat). So again, don’t be afraid of fat! You really do want to be hitting that 30% mark for total calories from fat if you want to optimize testosterone levels.

Okay so that’s been a lot of information, so let’s sum this all up so far. If you were to follow every testosterone optimization point we just talked about – meaning if you were training with 85% of your 1RM for 5 sets of 6 reps with 60 second rest periods for multiple exercises per training session. If you were taking the proper amount rest days depending on your experience and were getting 8 hours of good quality sleep every night. If you were eating mostly non-processed foods with a good deal of dark green vegetables and maintaining your body fat around 12% while still consuming 30% of your total calories from fat. If you were doing all of these things, you would have optimized your testosterone production to 99% and possibly even 100% of what it could be if we take unsafe exogenous androgen use off the table. The possible remaining 1% could come from additional supplementation that we really must discuss here given the amount of products that are claiming to be able to raise your testosterone by substantial amounts.

First lets talk about some vitamins and minerals that are purported to increase testosterone. Specifically, vitamin D, zinc, and magnesium have had such claims; however, there has not been scientific evidence to prove these claims. That being said, I do typically recommend supplementing all of these to all of my clients as I typically find most individuals to be deficient in these substances; however, they are simply not being taken testosterone purposes.

L-arginine is next up. It’s an essential amino acid that is a somewhat popular bodybuilding supplement due to its purported benefits of increasing nitric oxide which allows for vasodilation and thus better blood flow to the muscles during exercise. There have also been claims that it increases testosterone levels with some studies demonstrating this in rat models. In human subjects, the increase in testosterone in modest and limited to individuals with hypogonadism, or those with significantly low testosterone levels at baseline. For those that are not deficient in testosterone, L-arginine has not demonstrated any increase in testosterone with L-arginine.

Next let’s talk about herbal medicine. There are many herbs that claim to increase testosterone, but the only 2 that I am aware of that have any benefit at all are mucuna and ashwagandha. Both have been shown to modestly increase testosterone levels but as with L-arginine, only in individuals with significantly low testosterone levels at baseline. No such increase has been demonstrated in individuals with normal testosterone levels at baseline.

Finally, are the infamous testosterone boosters. These boosters are essentially marketed as “proprietary mixes” of herbs, vitamins, and minerals that have been purported to increase testosterone. It can be very frustrating to me to look these up and see that the first google search result is stating that they were shown to increase total testosterone by 15%. And this is the stat that is given without context, to sell these testosterone boosters to many people who frankly will not receive any benefit from them. This is why it is extremely important to be able to read scientific studies and understand their actual impact, conclusion and scope. This should honestly be a podcast in and of itself, but for our purposes here I will quickly say 2 things related to the topic. One, you need to make sure that the study is being done on humans. Just because a study demonstrates a testosterone increase in rats does not mean that it will demonstrate an increase in humans. This is often what is being reported in the case of some of these products that are claiming to increase testosterone. Then, even if it is in humans you need to look at things such as the type of study (i.e., is it a case study, a randomized-controlled trial, a meta-analysis, etc), the sample size of the study, and the methods and results. All of that can be covered on a separate podcast. But, the second main point I want to mention here though, is to look at who the participants are for the study. This is specifically relatable here because the studies used to claim that testosterone boosters are efficacious, are studies that, again, are done on those with hypogonadism, or with significantly low testosterone levels. This detail is often left out of marketing schemes in order to gain a larger clientele; however, it is crucial in understanding the actual population of people who will benefit from these testosterone boosters. So in sum, for the purposes of our discussion here on testosterone boosters – yes, some have been shown to be efficacious for those with significantly low baseline testosterone levels; however, there has no such demonstration of increased testosterone in those with normal, or low-normal baseline levels.

So wrapping up the discussion on all of these supplements. In sum, there are products that have been effective in increasing testosterone for individuals with significantly low testosterone at baseline. When I have a client who is known to be in this subset of the population, I do recommend some of these products with the specific product based on the exact situation. However, because none of these products have been demonstrated to increase testosterone in individuals with normal gonadal function, I do not recommend any of the products for this large subset of the population. Rather, 100% of your testosterone optimization will come from the principles we discussed previously.