Igf-1 and It’s Relationship to HGH - Performance vs. Longevity

The connection between HGH and IGF-1 in the body is clear. The pituitary gland manufactures HGH. Your liver then turns it into IGF-1. IGF-I and IGF-II are both potent growth factors involved in the development of your body including the central nervous system, brain’s receptors, biological activities, and it produces proteins that circulate through the blood brain barrier to reach the brain.

A primary and/or secondary IGF-1 deficiency is linked to a shorter lifespan. Research, while not done on humans, has shown that IGF1 gene inactivation or GH receptor inactivation in both rodents and invertebrates causes a deficiency in IGF-1 d, which results in a shorter lifespan. A deficiency in IGF-1 can be reversed using an IGF-1 supplement.

There was one study that did involve humans. That study involved men and it found that the 2 largest cohorts of patients with Laron syndrome, which is an inactive GH receptor that leads to an IGF-1 deficiency, took place in Israel and Ecuador. What it showed is that in spite of their dwarfism and obesity, patients were alive at the ages of 75 to 78 years, and some even lived longer.

Pure IGF Can Aide With:
Weight loss
Improved bone density
Aging
Endurance and energy
Immune system
Hair, skin and nails
Joint & connective tissue
Mental clarity
Stress reduction
Muscle growth

Optimizing for IGF-1, also known as the insulin-like growth factor-1, is one such case where more performance driven goals like maximizing growth and maintaining muscle and neurons may, to some degree, come at odds with ones desire for longevity. This is because in addition to insulin-like growth factor-1 being known for its role for building muscle, it has also shown some interesting properties that are not yet mainstream, and we will look at these.

IGF-1 and HGH Basics

IGF-1 and HGH are hormones that play complicated roles in aging. The relationship between the two is that GH is secreted by your pituitary gland, which stimulates IGF-1 production by action on your liver where it’s made. This close relationship between HGH and IGF-1 causes many to fuse the two together.

IGF-1 actually mediates the growth-promoting effects most of us associate with HGH, which has the features of both hormone and growth factor, because it stimulates the proliferation, growth, and survival of cells. There is also a negative feedback loop which reduces HGH production when there are elevated levels of IGF-1. The negative feedback loop is significant because IGF-1 improves the cellular survival of all your cells.

With age, comes a natural decline in the levels of HGH and IGF-1. GH levels follow a pattern through a person’s life. At birth, they are almost undetectable, at puberty they are at their highest point remaining steady through your 20s, 30s, and 40s, until around the age of 50 years when they start to significantly drop.

GH And IGF-1 Enhance Cognitive and Muscle Performance

IGF-1 plays a key role in promoting and maintaining your muscle mass and neuro function. IGF-1 and growth hormone things you need to know:
A 30-60 minute sauna session increases GH by 140 percent.
A person can adapt to the strenuous activity and not release less GH over time.
Exercise can encourage growth hormone release and thus IGF-1.
Exercised-induced neurogenesis is mediated through IGF-1 induced during exercise.
IGF-1 acts as a neurotrophic factor in the brain, contributing to the growth of new brain cells and survival of existing neurons.
IGF-1 is release in response to GH is anabolic promoting growth and repairing skeletal muscle.
This process of GH release in response to exercise is proportional to how strenuous the activity is.

The age-related decline in GH and associated IGF-1 is associated with age-related muscle atrophy, neuronal dysfunction, and increased adipose tissue. HGH replacement therapy in old men has shown to increase lean body mass. 1 mg/day of growth hormone therapy for 5 months has been used to improve cognitive function in both adults with mild cognitive impairment and healthy adults. While only modest amounts of GH cross the blood-brain barrier, IGF-1 has no problem getting across and it is responsible for the cognitive benefits. There is strong evidence that suggests that IGF-1 enhances performance and prevents the atrophy of the brain and the skeletal muscle.

The Trade-Off: Decreased Growth Hormone & IGF-1 Increase Longevity

Finding effective and safe ways to increase GH and IGF-1 naturally, improves muscle and brain function while it will concurrently prevent atrophy. Mice, flies, and worms were genetically engineered to be deficient in either GH or IGF-1 and what they found is that they lived nearly 50 percent longer than the controls, which is a significant increase in lifespan. The opposite has proven to be true, overexpressing GH by 100 - 1,000 fold in mice resulted in a 50 percent shorter lifespan, as a result of kidney and liver dysfunction.

The Longevity Mechanism

Why does decreasing GH and IGF-1 signal an increase in lifespan when it has a key role in muscle and brain function? It is believed that limiting IGF-1 levels rises the expression of other genes involved in stress resistance, particularly oxidative damage, which is generated daily through a number of ways including normal metabolism, and UV radiation, and it puts wear and tear all of your body’s tissues and your DNA. If you boost the activity of anti-oxidant genes that help to stave off this damage, then you can delay the deterioration of your tissue and our DNA, which provides longevity.

There are downsides to having low levels of IGF-1, including:

Brain dysfunction
Decreased fecundity and sterility
Diminished sex drive
Muscle atrophy
Stunted growth

All of these things will make you feel that you are living longer, which in this case is bad, because you are truly living longer!

Hormesis - An Alternative Longevity Mechanism

There are lifestyle factors that can also boost stress resistant genes without the downsides of too low of levels of GH and IGF-1 called hormesis, a low dose to something that would otherwise be considered harmful will increase the genes that deal with stress. The “hermetic effect” is the action of many catechins and polyphenols often mislabeled as antioxidants.

You can find catechins and polyphenols in:

Blueberries and other purple-pigmented fruits/vegetables
Dark chocolate
Green tea
Turmeric
Wine

On their own, catechins and polyphenols can’t scavenge free radicals like classic anti-oxidants. They are a little toxic to your cells inducing a hormetic response by increasing the antioxidant expression of genes.

It’s a trade-off when it comes to GH and IGF-1. More of it enhances muscle and neuronal growth while at the same time it prevents atrophy. Less of it will increase the stress resistance genes expression and extend your lifespan.

References

Sonntag, W. E., Csiszar, A., deCabo, R., Ferrucci, L. & Ungvari, Z. Diverse roles of growth hormone and insulin-like growth factor-1 in mammalian aging: progress and controversies. The journals of gerontology. Series A, Biological sciences and medical sciences 67, 587-598, doi:10.1093/gerona/gls115 (2012).
Velloso, C. P. Regulation of muscle mass by growth hormone and IGF-I. British journal of pharmacology 154, 557-568, doi:10.1038/bjp.2008.153 (2008).
Gatti, R., De Palo, E. F., Antonelli, G. & Spinella, P. IGF-I/IGFBP system: metabolism outline and physical exercise. Journal of endocrinological investigation 35, 699-707, doi:10.3275/8456 (2012).
Llorens-Martin, M., Torres-Aleman, I. & Trejo, J. L. Mechanisms mediating brain plasticity: IGF1 and adult hippocampal neurogenesis. The Neuroscientist : a review journal bringing neurobiology, neurology and psychiatry 15, 134-148, doi:10.1177/1073858408331371 (2009).
Rudman, D. et al. Effects of human growth hormone in men over 60 years old. The New England journal of medicine 323, 1-6, doi:10.1056/NEJM199007053230101 (1990).
Brown-Borg, H. M., Borg, K. E., Meliska, C. J. & Bartke, A. Dwarf mice and the ageing process. Nature 384, 33, doi:10.1038/384033a0 (1996).
Broughton, S. J. et al. Longer lifespan, altered metabolism, and stress resistance in Drosophila from ablation of cells making insulin-like ligands. Proceedings of the National Academy of Sciences of the United States of America 102, 3105-3110, doi:10.1073/pnas.0405775102 (2005).
Suh, Y. et al. Functionally significant insulin-like growth factor I receptor mutations in centenarians. Proceedings of the National Academy of Sciences of the United States of America 105, 3438-3442, doi:10.1073/pnas.0705467105 (2008).
Bartke, A. Growth hormone and aging: a challenging controversy. Clinical interventions in aging 3, 659-665 (2008).