What influence does cannabis from the cannabis plant have on your fitness performance such as muscle strength and muscle mass? What does it do, for example, to testosterone, cortisol, and growth hormone?
Cannabis in Fitness
Often, a question in the gym prompts an article. A while back, I was asked about the influence of cannabis use on building muscle mass. Besides addressing this question, I also thought it would be useful to explore the impact of the more popular substance, alcohol, on muscle growth. Lastly, I’ll also delve into the influence of sex on muscle growth, so we can cover all the pleasures at once. In this first part, I’ll address cannabis.
Cannabis Ergolytic or Ergogenic?
Cannabis, marijuana, weed, joint, wacky tobaccy, ganja, etc., amusingly enough, is on the list of prohibited substances by WADA (World Anti-Doping Agency) and the IOC [1]. I say “amusing” because substances on this list typically enhance performance and are therefore not allowed as doping. However, cannabis tends to decrease performance rather than enhance it.
It’s not without reason that in the States, employees are often tested by their employers for drug use, including cannabis, as it could decrease productivity and lead to unsafe situations due to impaired motor skills and concentration. Conveniently for African Americans, because apparently in states where there is no testing, they are less likely to get jobs due to the assumption that they use drugs [2].
In this regard, it is therefore an ‘ergolytic’ substance, meaning it impairs performance rather than ergogenic, performance-enhancing. The only benefits mentioned in a sports context are its ability to induce relaxation and promote better sleep (which is conducive to muscle growth). However, research has never shown whether and to what extent this would enhance athletic performance.
Yet, if you look at the list of athletes suspended for doping, you’ll find several athletes suspended for months to years because a metabolite (a substance that another substance can change into) of THC, the active ingredient, was found in their blood [3]. Not because it would improve performance, but simply because it’s on the list of illegal substances. It’s primarily prohibited because it would be contrary to “the spirit of sport”. Personally, I find that nonsense.
Shouldn’t I be able to decide for myself whether I smoke a joint for relaxation instead of having a beer if both don’t unfairly improve my performance compared to others? I shouldn’t be forbidden to light up a joint and chill on the couch because it might still be detected in my blood months later, but I can get totally drunk, celebrate my participation in an Olympic tournament on a boat, and cause half a million euros in damage [4]? Okay, of course, the German hockey team is blamed for the damage, but the IOC has no problem with boozing. As long as you don’t have an unfair advantage over other athletes, drug use, just like alcohol, seems to me to be a personal choice.
Smoking Weed and Muscles
But alright, weed and muscles. When discussing the influence of cannabis on the human body, you need to distinguish several things. Firstly, the active ingredient THC (delta-9-tetrahydrocannabinol) from the other components of cannabis (about 460 in total, of which 60 are cannabinoids).
Additionally, you need to differentiate between smoking marijuana and consuming it orally or through drinks. This is because of the difference in biological availability. When smoked, a maximum of 50% of THC ultimately enters the bloodstream, whereas for orally ingested THC, the maximum is 20% [5,6,7]. And when looking at the effects of smoking, you also need to consider the effects of tobacco with which it’s often mixed when not smoked pure. I will address these latter effects later in an article about the influence of cigarettes on muscle growth. Here, I will primarily focus on the influence of THC.
THC and Testosterone
There are many different opinions on the effect of THC on testosterone. Some studies suggest that it has no effect, while others show a decrease of up to 65% in testosterone levels after THC administration.
Before delving into this, I want to mention two studies that indicate that THC can at least disrupt the function of testosterone. In 1975, researchers already observed that muscle growth in rats caused by testosterone administration was absent when they also received THC [9].
Cannabis extract administration in combination with testosterone propionate (TP) inhibited growth stimulation produced by TP alone. Anti-androgenic nature of the compound is suggested.
P.V. Dixit
Later research from 1980 found a cause for this in the fact that THC and cannabinol (another component of cannabis) bind to the cell receptors for testosterone [10]. This prevents testosterone from functioning in the cells. Furthermore, THC metabolites are believed to have antagonistic effects on these receptors.
In addition, other metabolites of Δ9-THC were also androgen antagonists. This data suggests that the anti-androgenic activity of Δ9-THC and its metabolites may be responsible for the suppression of testosterone biosynthesis and other androgen-dependent functions.
H.A. El Sohly
This is in line with the observation that male long-term cannabis users have lower testosterone levels than non-users [11].
THC also affects the production of growth hormone (GH) and cortisol. Both substances are important for muscle growth. Cortisol is a catabolic hormone that causes muscle breakdown and fat storage, among other things. Growth hormone is, among other things, important for muscle recovery.
For cortisol, it’s known that smoking weed increases cortisol levels for 20 minutes after smoking, and drinking increases cortisol for 30 minutes. I couldn’t find studies on the influence of THC on GH levels, but given the above, you can imagine that THC, through its anti-androgenic and thus catabolic effect, also negatively affects GH levels.
For both cortisol and testosterone, however, it should be noted that while a single use increases cortisol and decreases testosterone, regular use appears to have the opposite effect. Chronic stress, for example, leads to continuously elevated cortisol levels, but chronic cannabis use (daily) leads to reduced baseline cortisol levels [12].
Similarly, while one study found lower testosterone levels in long-term users, another found no difference between users and non-users [13]. This suggests that your body adapts to the daily ‘stress’ of cannabis use by reducing cortisol and increasing testosterone levels, although not everyone seems to respond equally strongly to this.
This is also reflected in the muscle mass of long-term users. One study found that long-term cannabis users had lower muscle mass and fat-free mass than non-users [14]. On the other hand, another study found no difference in muscle strength between users and non-users [15].
It’s difficult to say whether this is due to individual differences or differences in study methods (e.g., how ‘long-term’ was defined). There’s a lack of good research into the effects of THC on muscle growth, unfortunately.
Conclusion
So, does smoking a joint affect muscle growth? It seems to depend on how much and how often you use it. Smoking weed once doesn’t immediately make you a slacker who loses muscle mass due to a decrease in testosterone levels. However, a single use temporarily increases cortisol and decreases testosterone levels, which is not very conducive to muscle growth.
But with long-term use, your body seems to adapt, leading to reduced cortisol levels and increased testosterone levels. However, this doesn’t mean that long-term use is good for muscle growth. Users have lower muscle mass and fat-free mass than non-users, although muscle strength doesn’t seem to differ between the two groups.
Whether this is due to individual differences or due to differences in study methods is unclear, but it does suggest that long-term cannabis use doesn’t seem to help with muscle growth and may even hinder it. So, in conclusion, if you want to build muscle, smoking weed isn’t the best way to go about it.
