Does HGH increase testosterone?
Human growth hormone (HGH) and testosterone are two important hormones that affect multiple aspects of health and fitness in both men and women. Here is a detailed overview of the relationship between HGH and testosterone:
- HGH and testosterone both decline with age - After peaking in our 20s and 30s, levels of both HGH and testosterone start to decrease by approximately 10-15% per decade. Keeping these hormones at healthy levels can help counteract many effects of aging.
- HGH helps stimulate testosterone production - Growth hormone has been shown in studies to directly stimulate Leydig cells in the testes to produce more testosterone. HGH signals to the cells to take up more LDL cholesterol into the mitochondria and use it to manufacture testosterone.
- HGH and testosterone work synergistically - Both hormones complement each other and help to amplify the other's effects. Some of the synergies include:
- Increasing protein synthesis and promoting muscle growth
- Mobilizing fats for energy usage
- Growing and strengthening bones
- Improving markers of cardiovascular health
- HGH therapy can increase testosterone levels - Clinical studies have shown HGH injections therapy to increase circulating testosterone levels in HGH-deficient men. In one study, testosterone levels increased by about 50% on average after 16 weeks of HGH treatment.
- Effect varies based on existing testosterone levels - Those with lower pre-treatment testosterone levels typically see a more dramatic boost in testosterone from taking HGH. Those already at normal testosterone levels may not experience an additional increase.
- HGH's impact requires adequate nutrition - The synergistic effect of HGH on testosterone is dependent on the availability of certain micronutrients that are required cofactors in the biochemical pathways of testosterone synthesis. Ensuring adequate intake levels through food and supplementation enables the full impact of HGH therapy.
- Taking testosterone may impact natural HGH - There is some evidence that external testosterone administration can reduce signaling to produce our own natural growth hormone, particularly in older men. This may occur through suppression of a key hormone called IGF-1. However, more research is needed.
- Stacking HGH and testosterone can amplify benefits - Due to the synergistic relationship between the two hormones, some athletes, bodybuilders and anti-aging clinicians use the practice of stacking - combining treatment protocols of both growth hormone and testosterone at the same time. Anecdotal evidence suggests this may provide amplified benefits vs just a single therapy, though it also increases potential side effects. Such off-label use should be carefully considered with medical guidance.
In summary, human growth hormone can directly increase testosterone production through signaling testicular Leydig cells. Through both direct and indirect mechanisms, HGH and testosterone work synergistically together to amplify many of their mutual effects relating to physical, sexual and cognitive performance. As we age and our bodies' production of these hormones decline, therapies to boost HGH and testosterone could provide significant benefits. However, use of such hormone therapies should be evaluated carefully with the guidance of a hormone specialist practitioner.