Short-term testosterone supplementation does not activate GH and IGF-I production in postmenopausal women.
Soares-Welch. Cacia C; Mielke. Kristi L KL; Bowers. Cyril Y CY; Veldhuis. Johannes D JD
Key Findings
- Testosterone levels rose 5‑ to 8‑fold with the patches, confirming the dosing worked.
- Neither low nor high testosterone altered pulsatile GH secretion, GH regularity, or total GH output after GHRP‑2 infusion.
- IGF‑I, IGFBP‑3, and IGFBP‑1 concentrations remained unchanged across placebo and testosterone conditions.
Practical Outcomes
- For biohackers hoping to boost GH/IGF‑I by short‑term testosterone supplementation, this study suggests it won’t work in postmenopausal women. Raising testosterone briefly is not an effective strategy to overcome age‑related GH decline, so focus on other GH‑stimulating methods (e.g., sleep, exercise, nutrition, longer‑term hormone strategies).
Summary
In a short 7‑day study, giving postmenopausal women a low or high dose of testosterone raised their blood testosterone levels a lot, but it did NOT increase growth hormone (GH) or IGF‑I levels, nor did it change how the body releases GH when stimulated with GHRP‑2.
Abstract
Testosterone (Te), oestradiol, GH and IGF-I concentrations fall in postmenopausal women. To test the effect of increased Te availability on impoverished GH/IGF-I secretion in this context. Placebo (Pl) and a low vs. high dose of Te were administered transdermally for 7 days to each of 15 healthy older women (ages 48-81 years) in a randomized, double-blind crossover design. Frequent blood sampling, GHRP-2 (Growth hormone releasing peptide-2) infusion, and deconvolution analysis were used to assess GH secretion. Graded Te supplementation increased serum Te concentrations (nmol/l) from 0.87 +/- 0.06 [Pl] to 5 +/- 1 [low] and 7.3 +/- 1.6 [high] (P < 0.001), but did not affect: (i) pulsatile GH secretion (microg/l/12 h; conversion factor: 1 microg/l = 0.33 mU/l), 29 +/- 7.2, 32 +/- 5.6 and 27 +/- 4.9; (ii) GH regularity (approximate entropy), 0.52 +/- 0.05, 0.57 +/- 0.05 and 0.56 +/- 0.05; (iii) IGF-I concentrations (microg/l; conversion factor: 1 microg/l = 0.131 nmol/l), 126 +/- 13, 135 +/- 15 and 141 +/- 13; (iv) IGFBP-3 (mg/l), 3.7 +/- 0.2, 3.6 +/- 0.1 and 3.7 +/- 0.2; (v) IGFBP-1 (microg/l), 41 +/- 2.3, 44 +/- 3.8 and 44 +/- 3.2; and (vi) the mass of GH secreted (microg/l/3 h) after GHRP-2 injection, 123 +/- 27, 146 +/- 32 and 147 +/- 38. Up to 8-fold elevation of Te concentrations for 1 week in postmenopausal women does not detectably amplify GH secretion or action, thus indicating that low androgen availability is not a proximate acute mediator of hyposomatotropism in postmenopausal individuals.
Study Information
pubmed
2005
2005-07-01T00:00:00.000Z
10.1111/j.1365-2265.2005.02294.x
7
61