Testosterone Dose Response

  1. Banned
    YellowJacket's Avatar
    Join Date
    Oct 2002
    Location
    In front of a computer. At all times.
    Posts
    0
    Rep Power
    0

    Testosterone Dose Response


    Testosterone
    Real-World Data
    by Tim Ziegenfuss




    If you've so much as picked up a newspaper in the last couple of weeks, or even a Time, Newsweek, Sports Illustrated, People, or friggin' Weekly Reader, you've no doubt been force fed yet another article about the horrors of steroids. Yep, steroids are no doubt what the terrorists are planning on dropping into our drinking water, thus creating a horrible epidemic of exploding livers and diminutive testicles that drop out of our pants like tiny popcorn kernels left over from last night's viewing of "The Secret Ya-Ya Sisterhood."

    Thankfully, there's some real world research going on about steroid hormones (not much, mind you, but some). Recently, researachers Shalender Bhasin, Linda Woodhouse, Richard Casaburi et al. (of Charles R. Drew University of Medicine and Science, Harbor-University of California Los Angeles Medical Center, Washington University School of Medicine) did a pretty tidy little study on our beloved Testosterone (in this case, the hormone, not the magazine).

    The title of the study is, "Testosterone dose-response relationships in healthy young men." As you might guess, they didn't study any 300 lb ripped-to-the-bone bodybuilders claiming to be drug free (yeah right). Instead, they focused on "normal" men and their responses to graded doses of this macho hormone.


    Subjects

    The subjects in this study consisted of 61 healthy men between the ages of 18-35 years. All had prior weightlifting experience, normal Tstosterone levels, and hadn't used any anabolic agents in the preceding year. All received monthly injections of a long-acting GnRH agonist to suppress endogenous Testosterone production (now that's gotta hurt). Depending on which group they were randomized to, subjects received one of five different weekly doses of Testosterone enanthate for five months (note: there were no significant differences between groups for any variable at the start of the study).

    Remember, these are the test subject's values at the time the study began.

    Group
    Dose
    Body weight (kg)
    Age (yr)
    FFM (kg)
    Basal T (ng/dL)
    Leg press strength (kg)

    1
    25 mg
    68.0
    28
    59.1
    593
    355.5

    2
    50 mg
    77.0
    29
    65.1
    566
    407.8

    3
    125 mg
    78.9
    28
    66.0
    553
    419.2

    4
    300 mg
    78.4
    24
    67.3
    654
    439.8

    5
    600 mg
    74.8
    25
    64.2
    632
    431.6



    Diet Control

    Two weeks before their first intramuscular injection, subjects began following a standardized diet consisting of 36 kcal/kg body weight per day (16.4 kcals/lb) and 1.2 grams protein per kilogram body weight per day (0.55 grams/lb). To put these values in perspective, a 176-pound male would have to ingest 2880 kcals/day and 96 grams of protein/day. To make sure subjects didn't change their dietary habits during the study, they were asked to complete 3-day food records and 24-hr food recalls every four weeks.


    Activity Control

    Here's the only part of the study that surprised me, at least initially — subjects were asked NOT to perform any type of strength training or endurance exercise during the entire study. This was done to avoid the potentially confounding influence that intense physical activity might have on the dependent variables. The more I thought about it, teasing out the effects that exercise might have on responses to Testosterone would have required an additional five groups (of men that did strength train). And as anyone who's done a research study will tell you, getting a sample size of 61 men is hard enough, but 120 men for a 20-week study? Yet another clear example of how time and monetary constraints influence research design.


    Outcome (dependent) Variables

    To underscore the comprehensive nature of this study, take a look at this list of outcome variables:

    • Fat-free mass (via underwater weighing and DEXA)

    • Fat mass (via underwater weighing and DEXA)

    • Thigh muscle volume (via MRI)

    • Quadriceps muscle volume (via MRI)

    • Total body water (via deuterium dilution)

    • Leg press strength (via 1-rep max)

    • Sexual function and desire (via daily logs)

    • Spatial cognition (via checkerboard test)

    • Mood (via Hamilton depression and Young manic scales)

    • Blood counts and clinical chemistries (too many analytes to list)

    • Prostate specific antigen (PSA)

    • Total cholesterol and various subfractions

    • Total and free Tstosterone

    • Luteinizing hormone (LH)

    • Sex hormone binding globulin (SHBH)

    • Insulin-like growth factor 1 (IGF-1)


    Statistical Gymnastics (oops, I mean analyses)

    This is where some very good studies sometimes go sour… incorrect analyses of the data (can anyone say repeated T-tests and type-II error?). Luckily, these researchers did their homework and used ANOVA to compare the changes from baseline among the five groups. They even examined all variables for their distribution characteristics and log-transformed those variables that didn't meet the assumptions of a normal distribution prior to analysis.


    Results

    Okay, here's what you've been waiting for. Let's start with hormone changes. Remember, weekly shots of GnRH assured that each subject's endogenous Testosterone production was at a minimum. Not surprisingly, 25 and 50 mg of Testosterone per week didn't "replace" what the GnRH had shut down. 125 mg/week seemed to keep total and free Testosterone at an even keel, while 300 mg and 600 mg/week doses led to roughly a doubling and quadrupling of Testosterone levels. LH was suppressed at all doses while SHBG increased only with the highest two doses.

    Relative to changes in body composition, the lowest two doses of Testosterone led to a significant increase in fat mass (eeew!) while the middle dose (125 mg) once again led to no change. Fat-free mass (aka lean body mass) increased by 5.3 kg (11.7 lb) in the 300 mg group and 8.5 kg (18.7 lb) in the 600 mg group. The ratio of total body water to fat-free mass didn't change in any of the groups, indicating that the increases in fat-free mass were not a result of water retention.

    On to muscle size and performance. Following suit, the lowest two doses had basically no effect on thigh or quadriceps muscle volume, leg press strength, or leg power. The 300 mg and 600 mg doses however led to significant increases in all of these parameters. Rather than confuse you with comma spices and annoyingly long sentences, here's what the data look like in table form (note: the % increases represent the change from baseline to week 20).


    Dose
    Thigh muscle volume
    Quad muscle volume
    Leg strength
    Leg power

    300 mg
    +9.9%
    +8.7%
    +16.4%
    +16.5%

    600 mg
    +15.7%
    +14.4%
    +17.7%
    +22.6%


    Sexual function, visual-spatial cognition, mood and PSA levels didn't change in any of the groups. None of the blood chemistry or organ toxicity values (e.g., creatinine, bilirubin, ALT, AST, etc.) were altered, with the exception of dose-dependent decreases in HDL-C that ranged from 10-20% (5-8 mg/dL), and a 9.9% increase in hemoglobin in the 600 mg group (the absolute value of 155.7 g/L was still within normal clinical limits, though).


    Conclusions

    Back in 1985, a researcher named GB Forbes speculated that there was a linear relationship between Tstosterone dose and lean mass accretion. For years, athletes and scientists have nonetheless disagreed about the effect of anabolic steroids on strength, muscle mass, and health status. The data from this thorough study support Forbes' assertion: weekly injections of Testosterone enanthate result in dose-dependent increases in muscle mass, muscle size, strength, and power. The downside is that HDL-C tends to take a nasty dip and at higher doses hemoglobin levels rise a smidgeon.

    On a final note, the researchers were quick to point out that there were considerable differences in the response to Testosterone administration within each group. Why? The most likely explanation is that Testosterone might differentially affect some (or all) of the many factors that are thought to control muscle growth, including: nutritional status, physical activity level, glucocorticoid, thyroid, and growth hormone levels, polymorphisms of the androgen receptor, myostatin levels, etc.

    So even though this research was super thorough, it, like most studies, left scientists with more questions than answers.

    As I read over this study for the tenth time, one thing is for sure: the athletes were right. Testosterone does increase strength, power, and muscle size without negatively affecting the kidneys, liver or, prostate — you just have to take enough of it (i.e., at least 300 mg/week). Now that Testosterone has been shown to improve muscle mass in the elderly, in normal men, and in those with wasting disorders, I wonder how long it will take for its rogue social status to disappear? Judging how the media handled the recent "anabolic steroids in baseball" scandal, we may still be a few decades away...


    Tim Ziegenfuss, Ph.D., CSCS is the Chief Scientific Officer for an industry-leading, pharmaceutically-licensed nutritional supplement company. Tim is also an Adjunct Professor of Nutrition at Kent State University and has monthly columns in Physical Magazine and Muscular Development. Previously, "Dr. Z" spent five years as a college professor, teaching (Anatomy/Physiology, Sports Nutrition, Exercise Physiology) and researching sports supplements (creatine, protein, pyruvate, androstenedione, androstenediol, ma huang, ribose). You can contact Tim with questions about training, nutrition, or supplement use at: tzphd@hotmail.com


    Reference

    Bhasin, S et al. (2001). Testosterone dose-response relationships in healthy young men. Am J Physiol Endocrinol Metab 2811172-E1181.

  2. Registered User
    DarCSA's Avatar
    Join Date
    Oct 2002
    Location
    USA
    Posts
    0
    Rep Power
    0

    Very nice man. I just have one question how can I volunteer for one of these studies. It would be nice to actually be a participant in something of that caliber. Great work again man.
  3. Registered User
    The Answer's Avatar
    Join Date
    Jan 2003
    Posts
    46
    Rep Power
    164

    Excellent Post YJ....This was a very interesting read

    Thanks
    TA
    •   
       

  4. Registered User
    MrTrap's Avatar
    Join Date
    Oct 2002
    Posts
    68
    Rep Power
    179

    Those are pretty impressive gains for not working out and eating a pretty mediocre diet.
  5. Registered User
    sage's Avatar
    Join Date
    Oct 2002
    Location
    seattle/new york
    Age
    33
    Posts
    1,617
    Rep Power
    959

    nicely done. possibbly just me, but i feel like this one of the better ones you posted. Layed out very nicely...easy on the eyes (ha) appreciate you sharing man. Sage
  6. Board Supporter
    raybravo's Avatar
    Join Date
    Oct 2002
    Age
    33
    Posts
    676
    Rep Power
    482

    another interesting study u guys might like to read ....

    J Clin Endocrinol Metab 1993 Sep;77(3):776-9 Related Articles, Links


    Testosterone administration increases insulin-like growth factor-I levels in normal men.

    Hobbs CJ, Plymate SR, Rosen CJ, Adler RA.

    Department of Clinical Investigation, Madigan Army Medical Center, Tacoma, Washington 98493.

    Although testosterone (T) administration can increase insulin-like growth factor-I (IGF-I) when administered to hypogonadal men, no studies have examined whether this occurs in normal men. The present study was undertaken to determine if an increase in IGF-I may be part of the anabolic effect of androgens. We enrolled 11 normal men in a randomized, double-blinded cross-over study. Subjects were assigned to receive either T enanthate (TE) (300 mg im, each week) or nandrolone (ND) decanoate (300 mg im, each week) for 6 weeks. After a washout period subjects were administered the alternate treatment. Pre- and posttreatment serum was analyzed for IGF-I by RIA after acid-ethanol extraction. Results expressed as mean +/- SEM (Table 1). IGF-binding protein-3 was measured by RIA and was unchanged in the TE treatment and decreased significantly after ND treatment. Although GH levels were not significantly different after either TE or ND treatment, they tended to increase after TE treatment (1.23 +/- 0.28 ng/mL vs. 3.3 +/- 1.03 ng/mL) but remained unchanged after ND treatment (1.68 +/- 0.68 ng/mL vs. 1.89 +/- 0.64 ng/mL). Serum total T levels increased 32 +/- 0.05 nmol/L in the TE-treated men, but fell by 7 +/- 0.02 nmol/L in the ND-treated men (P < 0.0001). Serum estradiol levels rose by 193.04 +/- 19.82 pmol/L in the TE-treated men although falling by 50.65 +/- 34.50 pmol/L in the ND-treated men (P < 0.0002). These data indicate that when normal men are given TE, serum IGF-I levels increase after 6 weeks of treatment. Treatment with ND did not change serum levels of IGF-I but did decrease the level of the major serum IGF-BP and therefore the level of bioavailable IGF-I may be increased in the ND group.
  7. Running with the Big Boys
    Matthew D's Avatar
    Join Date
    Oct 2002
    Posts
    5,019
    Rep Power
    0

    Great post YJ.. Just some of the info I was looking for

     
  8. Banned
    YellowJacket's Avatar
    Join Date
    Oct 2002
    Location
    In front of a computer. At all times.
    Posts
    0
    Rep Power
    0

    Thanks fellas, and great addition Ray...
  9. Registered User
    ready2explode's Avatar
    Join Date
    Jan 2003
    Posts
    33
    Rep Power
    157

    Great post...
  10. Registered User
    Chemical Evolution's Avatar
    Join Date
    Feb 2003
    Location
    Europe ____________________________ Chemical Evolution is a fictional Charecter presenting fictional facts, stories & opinions, None of witch should be substetuted for Professional Medical advice! ____________________________
    Posts
    6
    Rep Power
    144

    Originally posted by YellowJacket
    Thanks fellas, and great addition Ray...
    Yeah Very Nice CnP....

  11. Board Supporter
    raybravo's Avatar
    Join Date
    Oct 2002
    Age
    33
    Posts
    676
    Rep Power
    482

    Originally posted by Chemical Evolution


    Yeah Very Nice CnP....

    yeah lol , most stuf on the internet is posted from some other board onto the other bro , so ???

    anyway , studies are valid , so i dont see what the deal is .
  12. Registered User
    Chemical Evolution's Avatar
    Join Date
    Feb 2003
    Location
    Europe ____________________________ Chemical Evolution is a fictional Charecter presenting fictional facts, stories & opinions, None of witch should be substetuted for Professional Medical advice! ____________________________
    Posts
    6
    Rep Power
    144

    Originally posted by raybravo


    yeah lol , most stuf on the internet is posted from some other board onto the other bro , so ???

    anyway , studies are valid , so i dont see what the deal is .
    No problem Bro its just Nice to be "quoted" LOL
  13. Board Supporter
    raybravo's Avatar
    Join Date
    Oct 2002
    Age
    33
    Posts
    676
    Rep Power
    482

    Originally posted by Chemical Evolution


    No problem Bro its just Nice to be "quoted" LOL
    ohh lol , now i click on that link again and i realised its u who had posted that on that forum . lol , good job bro , and sorry if i came off as too arrogant .
  14. Registered User
    Lifeguard's Avatar
    Join Date
    Oct 2002
    Location
    LA County, CA
    Age
    30
    Posts
    602
    Rep Power
    447

    Very nice post YJ, Ray and CE, Karma for all.

     

    LG.
  •   

      
     

Similar Forum Threads

  1. Phyto-testosterone dosing
    By AtomicFox in forum Supplements
    Replies: 15
    Last Post: 06-15-2011, 02:08 PM
  2. Testosterone Cypionate Dosing Intervals
    By steve999 in forum Male Anti-Aging Medicine
    Replies: 13
    Last Post: 03-22-2009, 01:06 AM
  3. Half life dosing and blood testosterone concentration.
    By jhelumwarrior in forum Anabolics
    Replies: 2
    Last Post: 03-16-2009, 08:24 PM
  4. Testosterone from Herbs. Dosing? Timing?
    By stefang in forum Supplements
    Replies: 27
    Last Post: 04-15-2008, 11:45 AM
  5. Is FSH responsible for Testosterone only, Sperm only, or Both??
    By BigAk in forum Male Anti-Aging Medicine
    Replies: 3
    Last Post: 12-22-2006, 12:40 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in