TRT - How Healthy, Lean and Muscular Will Testosterone Replacement Make You? Data from Recent Meta-Analysis
|TRT - What to expect in terms of its effects on a man's body composition?|
In spite of the fact that the introduction of today's SuppVersity article focused on PED, the purpose of the meta-analysis and thus its summary was "systematically review [...] available observational and register studies reporting data on body composition in studies" in men with low or at least suboptimal testosterone levels.
The original meta-analysis by Corona et al. (2016) was published in the Journal of Endocrine Investigation, only a few days ago. It involved "an extensive MEDLINE, Embase, and Cochrane search [that] was performed including the following words: testosterone and body composition. And is thus not focussing exclusively on testosterone as a "new anti-obesity medication", which is how the authors refer to it in the very first sentence of the abstract, because "all observational studies comparing the effect of TS on body weight and other body composition and metabolic endpoints were considered" (Corona. 2016) in the scientists' meta-analysis. Here's an overview of the studies, their design an results, as they were summarized by Corona et al.:
Suggested Read: Testosterone Gel Augments Increases in Lean Mass Gains (+3.9kg in 6 Months) in Older Intensely Training Men, but Testim Blocks Decrease in Marker of Heart Disease Risk | more
- Rebuffé-Scrive et al. - no placebo group, 11 subjects, 1.5 months, mean age 42y, overweight/obese subjects, mean baseline T 13.8nmol/l, receiving TU 120–160 mg/day
- Forbes et al. (1991) - no placebo group, 7 subjects, 4 months, healthy, normal T levels, receiving TE 42 mg/kg/week
- Marin and Krotkievski et al. (1992) - no placebo group, 11 subjects, 1.5 months, mean age 42y, obese subjects, low T at 13.8 nmol/l, receiving TU oral 160 mg/day
- Marin and Krotkievski et al. (1996) - no placebo, 8 subjects, 3 months, mean age 42y, obese, low T at 14.1 nmol/l on T gel 250 mg/day
- Brodsky et al. (1996) - no placebo, 5 subjects with late onset hypogonadism (LOH) and T-levels of only 3.7 nmol/l on TC 3 mg/kg/2 weeks
- Katznelson et al. (1996) - no placebo, 29 subjects, 13 months, mean age 57, LOH w/ testosterone levels of 6.4 nmol/L on TE or TC 100 mg/week
- Wang et al. (1996) - no placebo, 67 subjects, for 6 months, LOH w/ starting T levels of 4.1 nmol/l taking T sublingually at 15 mg/day
- Zgliczynski et al. (1996) - no placebo, 22 subjects, 12 months, mean age 58.5y, normal elderly men with very low T (4.3 nmol/l) taking TE 200 mg/2 weeks
- Bhasin et al. (1997) - no placbeo, 7 subjects, 2.5 months, mean age 34.7y, LOH at initially 2.5 nmol/l receiving TE at a dosage of 100 mg/week
- Tan et al. (1998) - no placebo, 11 subjects, 4 months, mean age 33.3y, LOH w/ initially 5.5 nmol/l receiving TE at a dosage of 250 mg/4 weeks
- Brill et al. (2002) - no placebo, 10 subjects, 1 month, mean age 68.1y, but T-levels of 15 nmol/l treated with T patches at 5 mg/day
- Minnemann et al. (2007) - no placebo 25 subjects, mean age 57y w/ LOH and initial T levels of pretty high 14.3 nmol/l receiving TU 1000 mg/12 weeks from week 6
Suggested Read: Tribulus Boosts Testosterone (+12%), IGF-1 (+20%), Sheds 2kg (7%) Body Fat and Maintains Lean Mass in 12 Wk RCT | more
- Saad et al. (2007) - no placebo, 28 subjects, 13 months, LOH with erectile dysfunction (ED), low T at initially 7.5 nmol/l treated with TU at 1000 mg/12 weeks from week 6
- Saad et al. (2008) - 27 subjects, 9 months, mean age 60y LOH with ED and initial T levels of 7.5 nmol/l treated with TU 1000 mg/12 weeks from week 6 or T gel 50mg/day
- La Vignera et al. (2009) - no placebo, 7 subjects, 3 months, mean age 58y, LOH with MetS and unknown baseline T levels treated with T gel 50 mg/day
- Moon et al. (2010) - no placebo, 133 subjects, 6 months, mean age 54y baseline T of 8.6 nmol/l treated with TU at 1000 mg/12 weeks from week 6
- Permpongkosol et al. (2010) - no placebo, 161 subjects, 13.5 months, mean age of 60.4y and LOH consulting urological center w/ T at 9.4 nmol/l on TU 1000 mg/12 weeks from week 6
- Garcia et al. (2011) - no placebo, 29 subjects, treated for 25.5 months, mean age 55.5y, LOH and diabetes, no baseline T available, treated with TU 1000 mg/12 weeks from week 6
- Schwarz &Willix (2011) - no placebo, 56 subjects, 18 months, mean age 52.3y, overweight or obese with baseline T of 15 nmol/l receiving TC 80–200 mg/week + diet + training
- Arafa et al. (2012) - no placebo, 56 subjects, 12 months, mean age 55.5y w/ T2DM and unknown baseline T treated w/ TU 1000 mg/12 weeks from week 6
- Schroeder et al. (2012) - no plaebo 29 subjects, 4 months, mean age 71y, baseline T of 13.1 nmol/l treated with T patch 5 or 10 mg/day
- Jo et al. (2013) - no placebo, 18, 26.8 months, mean age 35.9y and suffering from Klinefelter syndrome, with low T at 3.1 nmol/l at baseline treated w/ TU 1000 mg/12 weeks from week 6
What is the Klinfelter syndrome? That's a genetic disorder that affects males. Klinefelter syndrome occurs when a boy is born with one or more extra X chromosomes. Most males have one Y and one X chromosome. Having extra X chromosomes can cause a male to have some physical traits unusual for males.
- Ko et al. (2013) - no placebo, 246 subjects, 14.7 months, mean age 58.5y treated w/ TU 1000 mg/12 weeks from week 6
- Rodriguez-Tolrà et al. (2013) - no placebo, 50 subjects, 12 months, mean age 59.1y, LOH, mean T at baseline 10.2 noml/l treated w/ T gel 25–100 mg/day
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- Tirabassi et al. (2013) - no placebo, 15 subjects, 18.5 months, mean age of 55.7y, LOH w/ baseline T levels of 5.2 nmol/l on TU 1000 mg/12 weeks from week 6
- Zitzmann et al. (2013) - no placebo, 1438 subjects, 10.5 months, mean age 49.2y, LOH w/ baseline T levels of 9.6 nmol/l on TU 1000 mg/12 weeks from week 6
- Francomano et al. (2014) - no placebo, 20 subjects, 60 monhts, mean age 57.5y, MetS and basline T of 8.3 nmol/l on TU 1000 mg/12 weeks from week 6
- Pexman-Fieth et al. (2014) - 669 subjects, 6 months, 53y, LOH on T gel 50, 75 or 100 mg/day
- Yassin et al. (2014) - no placebo, 261 subjects, 54 months, mean age 59.5y, LOH w/ baseline T levels of 7.7 nmol/l treated w/ TU 1000 mg/12 weeks from week 6
- Zitzmann et al. (2014) - no placebo, 381 subjects, treated for 60 months, mean age 42.6y w/ LOH and low T at 5.2 nmol/l on TU 1000 mg/12 weeks from week 6
|Table 1: Number and proportion (%) men reporting use of AAS, life-time, past 12 months and past 30 days, in different subgroups (Leifman. 2011).|
To be more specific, "[t]he estimated weight loss and WC reduction at 24 months were −3.50 [−5.21; −1.80] kg and −6.23 [−7.94; −4.76] cm, respectively" (Corona. 2016). In addition, the provision of testosterone was, as you would probably have guessed based on previous SuppVersity articles, "also associated with a significant reduction in fat and with an increase in lean mass as well as with a reduction in fasting glycemia and insulin resistance" that were accompanied by reductions in fasting glycemia and insulin resistance (IR), as detected by HOMA-IR index - especially in studies enrolling a diabetic subject clientele at baseline (Corona. 2016).
|Figure 2: Effects of TRT on blood pressure, lipids and glucose metabolism (Corona. 2016).|
|Figure 3: Effect of TS on waist circumference (cm) in the studies that were part of the meta-analysis (Corona. 2016).|
|Figure 4: Zitzmann et al. also found sign. improvements in mood (left) and the ability to concentrate (right) in their previously (mostly) hypogonodal subjects (Zitzmann, 2014).|
You to know more about superphysiological doses?If that's not "good enough" for you, let me remind you of my previous review of a seminal paper by Bhasin et al. who conducted (to my knowledge) the only "dose-escalation" study that comes remotely close to being a "PED"-RCT, i.e. a controlled trial that may give us some insights into the effects T at dosages that are used by performance enhancing drug users would have.
|Figure 5: Dose response relationship of muscle gain (in kg) per mg of testosterone enanthate (left) , the white line indicates a dose that would probably have produce testosterone levels identical to baseline; and relative change in lean and fat mass in response to changes in serum testosterone levels (right | Bhasin. 2001)|
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- Bhasin, Shalender, et al. "Testosterone dose-response relationships in healthy young men." American Journal of Physiology-Endocrinology And Metabolism 281.6 (2001): E1172-E1181.
- Corona, G., et al. "Testosterone supplementation and body composition: results from a meta-analysis of observational studies." Journal of Endocrinological Investigation (2016): 1-15.
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- Zitzmann, Michael, et al. "IPASS: a study on the tolerability and effectiveness of injectable testosterone undecanoate for the treatment of male hypogonadism in a worldwide sample of 1,438 men." The journal of sexual medicine 10.2 (2013): 579-588.