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Testosterone and Muscle Size/Muscle Strength/Athletic Performance?

Perhaps a dumb set of questions. Bear with me if so.

We know that supraphysiolgical testosterone levels promote increased muscle growth and enhanced nutrient partitioning.

We also know that supraphysiological exogenous testosterone and growth hormone administration will improve peak anaerobic output. I’m thinking specifically, here, of the 2010 study by Dr. Ken Ho, et al, that showed the equivalent of a 0.4 improvement in the 100 meters with 8 weeks of GH usage, and nearly double that with co-administration of testosterone (http://annals.org/article.aspx?articleid=745760). This, despite the fact that the GH alone didn’t add to muscle mass directly, so there was presumably some other mechanism at play (other than larger muscles) that accounted for the improved anaerobic performance for the GH-only group.

However, I’m weighing this against a 2009 study by West, et al, that asserted that an increase in endogenous testosterone (and GH and IGF-1) levels through high-intensity leg exercises did not affect the rate of anabolic signaling or protein synthesis - the group with high testosterone levels, from the extra test-boosting exercises immediately after doing curls did not build muscle or increase their strength any more than the group that just performed the curls (http://www.ncbi.nlm.nih.gov/pubmed/19736298). I’m also thinking of another study, that I can’t remember exactly, that showed that women - with many times less testosterone - grew muscle at the same rate as men when resistance training. The extra testosterone for men didn’t give them any increase in proportional muscle growth or proportional muscle strength.

Finally, I’m remembering a paper by Peter Weyand that casually mentioned that the likely reason for women’s proportionally-slower top sprinting speed was their increased fat mass, rather than anything to do with neuromuscular or strength benefits of testosterone. He mentioned that the difference between men and women’s world records in the 100, 200, and 400 meters is roughly 10% - and men and women tend to have similar differences in fat mass.

Developing on that: it seems that exogenous testosterone administration boosts women’s performance more than men’s, especially at higher dosages. I’m thinking of the fact that so many women’s track and field world records from the 1980s are still untouchable. Back then, it was easier to go with super-duper physiological dosages and avoid detection than it is now, where I assume most professionals are on merely super dosages. Men, on the other hand, are still smashing world records that were set by obviously-assisted athletes from the 1980s.

So, my basic question is: what’s going on with all this?

  1. Does testosterone provide any immediate boost to muscular strength/power output that is independent of any muscular hypertrophy gains?
    1a) If testosterone does not provide any such effect within the physiological ranges, does it do so at supraphysiological levels? If so, what’s the difference?

  2. Does testosterone function differently vis a vis muscular(/neuromuscular) strength and hypertrophy improvements between men and women?
    2a) If not, does it do so at suprahysiological levels in some different way?

  3. Would TRT that takes a man from below-normal into the normal or high normal range have any or many noticeable effects on muscle size or strength/power output? That is, a guy going from 200 to 900 ng/dl Total, 50 to 220 Free T - would he see a similar proportional boost in hypertrophy or athletic performance as a guy going from 700 to 3,150?

Maybe this belongs in Pharma, but I thought I’d ask it here because there are so many guys going on TRT or SERMs that cite insufficient workout results as at least one reason for wanting to boost their T. Is there reason to believe that anyone will see significant improvements if they never get above the physiological range?

(FWIW, I’m looking at the Ho, et al, study and it appears that these are the changes for the testosterone + GH group:


Week 0: 14.8 nmol/L
Week 8: 36.6 nmol/L


Week 0: 666 ng/dl (eek)
Week 8: 899 ng/dl

Lean Body Mass:
Week 0: 61.9 kg
Week 8: 68.5 kg

Wingate Test value (anaerobic work capacity):
Week 0: 22.4
Week 8: 23.9
Week 14 (after 6-week washout period): 23.1

Week 0: 185kg
Week 8: 185 kg
Week 14: 200kg

Vertical Jump:
Week 0: 53.9cm
Week 8: 54.6 cm
Week 14: 56.6

So the results are not as straightforward as I described:
Deadlift didn’t increase for T+HGH group, despite increase in lean muscle mass, within the 8 weeks - but then jumped up when re-tested later.

Vertical jump improved slightly for T+HGH group within 8 week period…but the improvement was less than the Placebo group experienced in the same time frame. However, after the washout period, the vertical jump was even higher - an effect the Placebo group didn’t exhibt.

Wingate value jumped for the T+HGH group by nearly 9% and remained significantly elevated 6 weeks after T&HGH was discontinued. The HGH-only group showed about half that rate of improvement within 8 weeks and remained similarly elevated after washout.

Most significantly, if I’m reading this right:

Total Testosterone value only went up about 300 points for the T+HGH group! That’s less than most Clomid users will experience and only took the group to the high-normal range. The treatment was 250mg/wk of Test-Sustanon intramuscularly. Looks like the Test injections only began in Week 3 - so there was only 5 weeks of testosterone usage, at slightly higher than TRT values.

I have no idea what the IGF-1 reference ranges are, so I don’t know how big that increase really is.
GH treatment was somatropin 1mg/ml at:
Week 1: 1 mg/day
Week 2: 1.5mg/day
Week 3-8: 2.0mg/day
Again, I know nothing about HGH and so don’t know how big these doses are.

So, testosterone (from mid-range to high normal range) +HGH (?):

  • No significant strength increases
  • Increased lean muscle mass
  • Increased anaerobic work capacity
  • Increased vertical jump

Anyone want to explain the causality of any of this?

Yes. I was at 190 and went to 575 via clomid and I have noticed great improvements. There may not be any statistically significant increase in the rate of improvement (though I would argue there IS) as shown by studies. However, I’d argue that your “genetic maximum” is greatly reduced. My 5x5 bench press before clomid was 165lbs and I was really unable to push it farther. I was exhausted, weak and ended up injuring myself. After the injury and a deload (all within a few months) my 5x5 BP is 185 and going up. All my lifts pretty much stalled out in the beginner / low intermediate range. No blood, sweat and tears would push them any higher. After clomid, they are all going up again.

Thanks for the feedback.
I was very impressed with what I perceived to be strength and athletic gains after beginning Clomid. I had an approximately 115% increase in Free T after 1 month on Clomid 50mg/day.

Looking back on it, the gains appear to be less comprehensive than I originally believed:

Sprint Performance: There was a statistically significant (3%) improvement in my 20 meter sprint performance from a crouch start. However, my peak velocity (generally obtained by 45 meters of sprinting) did not appear to be any better than prior to Clomid.

Weightlifting: My improvement was somewhat like yours - I noticed it in my improved ability to do repeated submaximal lifts. For me, I went from handling 185lbs on bench press for 3-4 sets of 5 reps to being able to do 5 sets of 5 reps fairly easily. However, I did not notice that it was any easier to lift anything closer to my old 1RM, which was around 235-240. Doing reps at 200 and up is still quite difficult. I have not tried to do a 1RM since beginning Clomid.

For power cleans, I did not notice any improvement in 1RM, nor did working submaximally feel any easier than pre-Clomid. This may be due to the fact that I stopped doing power cleans for a few weeks, however.

Jumping: repeated plyometric performance was improved; I can cover significantly more ground doing 10 “bounds” than before. However, 1 rep vertical jump max did not improve at all.

This is all still really early in the game (above numbers/examples all within 2 months of beginning Clomid), so it’s possible the ergogenic effects will compound as I continue. It’s possible that my lack of improvement in top sprint speed is a function of increased fat mass - I started eating more and slightly worse after I began Clomid. It’s possible this negatively impacts top speed more than the start, because the start features longer opportunities to “push”, whereas upright running has decreased ground contact times and the power is mostly generated at the moment of footstrike, rather than “pushing” during ground contact.

If anyone else has anecdotal or scientific results to share, please do.

I note this study (http://press.endocrine.org/doi/full/10.1210/jc.2002-021231) shows dose-dependent increases in maximal strength, but I’m not sure I can parse out whether these strength increases are in direct proportion to muscle mass increases. That is, did the group with 600mg test/week feature greater or just comparable strength increases to the 300mg/week group when you control for the amount of muscle mass added by each?

That gets to my 1st listed question: does testosterone (at whatever dose) increase strength or power strictly by way of increased muscle mass, or are there alternative mechanisms for power expression that testosterone enhances? For instance, does it enhance energy-source-usage efficiency in some way? I think that’s suggested in the Dr. Ho paper but I’m not sure.

There can be strong effects on TRT candidates because you are comparing to their states with low T levels. With low T you are getting a catabolic state, muscle wasting and often strong estrogen dominance.

There are many stories, here is mine.

Have always been slim and never gained much weight one way or the other.

Started TRT and waist went from a flabby 34" to 32" in a few months, later on to 31" when E2=22pg/ml. And during that period of fat loss, my weight did not change. All that that was doing normal low effort daily activities, no training or exercise other than evening walks when weather was nice. So my natural tendancy for this was enabled with TRT. That was on 100mg T cyp per week and TT=900pg/ml.

Many years later at 65YO I started training twice a week, now 67. Could not really gain weight, but did gain mucle, so BF going down. But now getting to around 5 pounds heavier that 10 years ago when I started TRT. My genetics do not allow for a large gain in muscle mass. Now taking Rx 1.5iu GH and that may help, to soon to tell.

Thanks for the story.

The estrogen dominance thing is interesting. For athletic performance, the increased fat mass brought on (or co-morbid with?) by increased estrogen levels would have a substantial effect. In running, fat mass is obviously dead weight. Take a 200lb guy from 30% body fat (60 lbs) down to 10% (20 lbs) and he’s basically no longer running with a 40lb backpack on.

For strength in general, having a higher proportion of bodyfat means a lower proportion of muscle mass at the same bodyweights - meaning a 200 lb guy at 30% has less muscle mass to utilize in pushing weight than a 200 lb guy at 10%.

This is all really obvious, but I’m just musing about the difference in effects here:

  • Lower testosterone results in muscle wasting and therefore reduced muscle mass
  • Higher estrogen results in (or is caused by?) increased amounts of adipose tissue.

Reduced muscle with the low testosterone and “worse” nutrient partitioning. Increased fat and also “worse” nutrient partitioning with the estrogen. Am I off here?

Some of us low-T guys are also lower on the E side of things; I was at 14 pg/ml when my T was in the mid 300s. So any performance detriments were probably more attributable to low T than high E. Right?

I’m 54yo. Started lifting about 18 months ago. Also lost 30lbs in first year. About 4 months ago I started TRT. In that time, I’ve seen a good increase in LBM. Great increases in strength. I can eat a lot without gaining fat.

What were your numbers before and after beginning TRT? Just curious about the range of the increase.

I’d have to dig my pre TRT labs up. I was pretty low. I’m having blood drawn tomorrow. I think my E2 is up. I let you know when I get the results.

Thank you, sir. Look forward to it.

My pre TRT TT was around 325 with strong symptoms. Can’t recall FT. I was certainly not extremely low compared to others here.

My pre TRT was 319 and 6.5. I had a follow up saliva test (I know, some here hates saliva testing) it was 32 which is low for a 77 year old man! I also had severe symptoms.

I’m also gaining muscle on a cut, something that has never happened before. The best I could figure was that I could put on 1/4-1/3 pound muscle but to do it, I’d have to gain 1lb fat. Bad ratio. Then, when I would cut, I’d lose pretty much all the gains. I have even noticed a change from going from 12.5mg clomid (575T) to 25mg clomid (haven’t tested T since).

Totally sucked, I don’t know if you could even compare before and after. I don’t know where the studies come from that find no differences.

Well, the study that found no difference showed no difference with anabolism between the group that had “exercise-induced” testosterone gains and the group that had no testosterone gain. I can’t find the figures, but I would guess the boost wouldn’t be more than 100 ng/dl for the exercise-induced group, if it’s even that much.

On the other hand, you had a 385 ng/dl improvement in total test (and, if you’re like me, probably a larger proportional boost in free test). You experienced a greater than 200% increase in total testosterone. The analogous situation for someone without hypogonadism would be going from 700 to 2,100 ng/dl. That would, unquestionably, manifest itself with some pretty rapid muscle gains.

But my question is: does it work linearly like that? That is, could you expect the same proportionate increases in strength/muscle mass with the 190-575 jump as the guy with the 700-2,100?

Being at 2,100 is a higher absolute value. However, if women are able to add muscle at a similar rate to men - or even with a much slower/lesser rate - despite having a fraction of male T-levels, maybe it’s not absolute values that are most relevant?

Just trying to parse this all out and make sense of it. Maybe I should cross-post this in Pharma.

Nothing in biology is linear. Linear doesn’t exist except on graph paper.

Ok, I’ll throw out a theory. No difference in anabolism is explained that everyone in the study is a total beginner (is this true?) and everyone gained muscle at a decent rate because they never touched iron before. So, if you assume everyone is below their “genetic max”, maybe the rate doesn’t change. BUT, when they leave “beginner” level weights, changes in T become more pronounced.

And of course, T levels are only one part of the strength and muscle building equation. Genetics are probably the most important factor. Other things like diet, training, other diseases, age, etc. will all greatly effect outcomes.

All I have is anecdotal evidence. I’m actually surprised by my strength gains. I’m actually getting looks from much younger, much bigger guys at the gym. You can kinda see them thinking. Wow, that’s pretty heavy for an old guy. Lol

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Just found the full study. You’re right in your assumption that they were mostly beginners - they’re described as “healthy young men” with a mean age of 20 and no formal or regular weight training history.

It’s hard for me to clearly interpret the rate of change for the testosterone from the graph. Someone correct me if I’m wrong, but it looks like testosterone went from 11-12 nmol/l (low-mid 300s for ng/dl) up to nearly 30 nmol/l (800s ng/dl) 15-20 minutes after the workout…but then returned close to baseline after about an hour. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790261/

The testosterone boost from testosterone-boosting exercises (heavy compound lifts) therefore appears to be significant BUT transitory. That makes the lack of any differences in signaling or synthesis rather predictable - there’s just not much time for the increased testosterone to DO anything in 45 minutes. On the other hand, TRT/SERM guys have much more stable and long lasting Testosterone increases.

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Looks like apples and oranges. I don’t think you will be able to extrapolate those studies and TRT folks. Seems like these folks with transient increases would spends a lot of time in a catabolic state between workouts. Whereas the TRT folks would be in an anabolic state for much longer periods.

Right, that’s what I was getting at in my last post. I guess a better way to phrase my question about proportional gains is this:

3a) Let’s say a 200 lb guy, 10% body fat guy on a mild testosterone-only cycle went from 700 ng/dl to 2,100 ng/dl and experienced a 5 lb increase in lean mass over one month. I’m just making up these numbers, but run with me. With that 200% increase in testosterone levels, he was able to add 2.7% in lean mass.

(200 lb guy with 10% body fat has 180 lb fat free mass; 5 lbs is 2.7% of 180. Correct my math if I’m wrong)

Another 200 lb guy is hypogondal and at 15% body fat. He gets on Clomid or a conservative TRT dose. He goes from 200 ng/dl to 600 ng/dl, a 200% increase. Would we expect him to see a 2.7% increase in HIS muscle mass over one month?

(200 lb guy with 15% body fat = 170 lb fat free mass; 2.7% of that is 4.59 lbs - correct my math if I’m wrong).

In this hypo, that is, would we expect the TRT guy to gain about 4.5 lbs of lean muscle mass (by going from below the normal range into the normal range) in proportion with the guy going from the normal range to the supraphysiological range?

3b) Same question, but for strength.

Guy 1 deadlifts 400 lbs before cycle. He cycles at same protocol outlined above. He deadlifts 450 lbs after 1 month. 12.5% increase.

Guy 2 deadlifts 350 lbs before beginning TRT or Clomid. Sees same increase as outlined above. Would we expect him to have a 43.75 lb increase up to 392.75 lbs at same amount of time?

These may have obvious answers or impossible to determine answers. No idea.

Just for fun, you should probably be looking at FT rather than TT as it is the free T that does the magic. Anyway, I don’t think you can compare something so complex by looking at one factor. It’s like looking at HTN meds. They all lower BP, but how much is very individual and is determined by too many factors to list.