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Human Growth Hormone and Testosterone – The Relationship

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Boost your knowledge of hormones to ramp up your muscle gains

You’re here because you want to improve the way you look and feel. You want to optimize your hormones and get back that muscular, athletic physique you once had.

But when it comes to complex interactions between hormones, they can be confusing. There’s just so much to take on board that you just don’t know where to start.

But worry not, because in this article we’ll break down all you need to know about the two main players – growth hormone and testosterone.

Exactly how do these two important hormones interact to ensure muscle building and fat loss?

Let’s find out…

What is Testosterone?

Testosterone (T) is a steroid hormone synthesized from cholesterol and released into the bloodstream from the Leydig cells of the testes.

Commonly considered to be the most potent naturally-occurring male anabolic-androgenic hormone, T is responsible for a number of actions. These include:

  • Elevates protein synthesis and promotes an increase in both bone and muscle mass
  • Ensures optimal body composition (decreases belly fat and gynecomastia)
  • Regulates sexual characteristics, libido and performance
  • Boosts strength, masculinity and dominance
  • Decreases cardiovascular, cognitive and metabolic disease risk

How to increase T levels

When your T levels are optimized, you feel like a man. A strong, masculine and assertive man who not only feels great, but looks great too.

Most men though find that as they age their testosterone production naturally begins to slow down. By the age of 40, a surprising amount of men have clinically low levels. And with that comes the loss of all of this hormone’s benefits.

Testosterone can be increased through proper nutrition, exercise training and an overall healthy lifestyle. Many scientists believe that the loss of T levels isn’t through ageing itself, rather the accumulation of poor lifestyle.

And that’s where supplementation comes in.

T can also be increased naturally with the use of a testosterone booster supplement that stimulates T production naturally and safely.

Alternatively, T can be elevated by the more risky use of anabolic steroids (AAS) or testosterone replacement therapy (TRT). But whilst these do work in some people, they come with a number of inherent risks and dangerous side effects.

Male model man smiling on blue background

Key Point: Testosterone is a naturally-occurring steroid hormone that regulates masculinity and promotes health.

What is Human Growth Hormone?

Growth hormone (GH) is a peptide hormone produced by the pituitary gland located in the brain. Unlike testosterone which is formed through molecules of cholesterol, GH is formed via amino acid chains.

GH isn’t released constantly by the pituitary gland, but rather in short pulses throughout the day.

Healthy men produce around 5 ng.mL of growth hormone in the blood.

Females produce more (anything from 6 to 120 times more) in order to maintain an environment suitable for child-bearing, and it’s relationship to estrogen.

When released into the bloodstream, growth hormone has a number of important functions such as:

  • Promoting growth of tissues in children and maintaining growth in adults
  • Stimulates the liver to release another anabolic hormone called insulin-like growth factor 1 (IGF-1)
  • Maintains immune function
  • Increases muscle mass through protein synthesis
  • Increases fat loss by triggering lipolysis

Growth hormone homeostasis

Also known as somatotropin, GH works on a finely tuned axis, with just the right amount needed to ensure optimal growth of tissues.

Homeostasis refers to the equilibrium of hormones.

It suggests that a certain amount of a hormone is needed for the body to work properly – but too much or too less can cause problems, especially to physiological processes.

If your body doesn’t produce enough GH, a variety of development disorders may occur, particularly during childhood. In adults, low growth hormone levels can lead to fat gain, heart problems and weak muscles and bones.

But producing too much of the hormone can lead to acromegaly – a disorder characterized by too much growth in tissues, particularly hands and facial bones. It can also lead to gigantism which results in a large increase in height.

Young, athletic man in a white shirt against a grey

Can You Increase GH Levels Naturally?

Yes you can. And you can increase it naturally in a number of ways:

  • Diet – consuming sufficient protein and amino acids
  • Exercise – strength training works well
  • Sleep – good quality and quantity sleep each night is key to elevating hormone levels

Interestingly, vitamin D supplements have also been found to elevate growth hormone levels and circulating IGF-1 too [1].

Through a proper lifestyle program, you can really optimize levels of this hormone and all of its benefits. Unless you have a GH deficiency (as diagnosed by your doctor), you won’t need growth hormone drugs.

Human growth hormone drug use

If you have a growth hormone deficiency then your health professional may suggest that you take prescribed hormones in recombinant form. This means that it’s essentially a synthetic drug.

Although a banned substance according to the World Anti-Doping Agency (WADA) and the International Olympic Committee (IOC), growth hormone is still abused by some athletes and bodybuilders.

These drugs can be purchased by various pharmaceutical companies, but often contain contaminants due to them being unregulated.

Side effects of HGH use

Much like anabolic steroids, the are a number of side effects that make taking GH as a drug very dangerous. These include an increased risk of diabetes, water retention and low blood sugar. HGH can also massively increase your risk of congestive heart failure too.

Another side effect is the generalized enlargement of organs, not just muscles. Your liver and pancreas in particular can become bigger which is probably the contributing factor to diabetes.

Long term, there’s also a strong correlation between human GH drug use and acceleration of cancer-related tumors too.

African man showing his six pack abs and chiseled muscles

Key Point: You can elevate GH levels naturally through exercise, diet and a healthy lifestyle.

Testosterone and Growth Hormone Interactions

Based on their effects, T and GH do show some crossover roles – particularly with regards to their anabolic effects on protein metabolism [2].

If you narrow the two hormones right down you’d say that GH is involved in development and growth, and T is more to do with androgenic characteristics and growth – very similar but with their own little niches too.

They both play an important role in growth, ageing, health and performance. 

Together, T and GH encourage protein cell growth and energy release, as well as the breakdown of fats – a process referred to as partitioning.

Essentially, these two hormones choose where energy comes from, and when optimized, decide that stored energy from fat is top of the list.

Both hormones are involved in growth and metabolism

Growth hormone and testosterone have an almost synergistic relationship when it comes to their physiological processes.

During puberty, it is the combination of these two hormones that helps with development, maturity and growth [3].

And whats’ more; testosterone helps to increase or ‘modify’ the strength of growth hormone in tissues due to its androgenic-anabolic effects [4].

Key Point: Growth hormone and testosterone are both involved in regulating growth, metabolism and health.

Test Booster or HGH?

Because both anabolic steroids and growth hormone carry so many inherent risks (and are both banned substances), we suggest that you avoid both of these drugs altogether.

Natural testosterone boosters however, can elevate T levels by stimulating your body’s own hormone boosting ability. They don’t flood your blood with exogenous, synthetic hormones. Instead they gently nudge your testes into producing more of your own T.

Hormone support from T booster supplements is safe because they contain only natural ingredients such as vitamins and minerals, and have shown to be effective in a number of rigorous clinical trials.


  1. Ameri, Pet al. Vitamin D increases circulating IGF1 in adults: potential implication for the treatment of GH deficiency. Euo J Endocrinol. 2013; 169(6): 767-72
  2. Birzniece, V et al. Interaction between testosterone and growth hormone on whole-body protein anabolism occurs in the liver. J Clin Endocrinol Metab. 2011; 96(4): 1060-7
  3. Rizvi, SS et al. Testosterone modulates growth hormone secretion at the hypothalamic but not at the hypophyseal level in the adult male rhesus monkey. J Endoc. 2000; 165: 337-344
  4. Zachmann, M. Interrelations between Growth Hormone and Sex Hormones: Physiology and Therapeutic Consequences. Horm Res. 1992; 38: 1–8