Differences and similarities between HGH and testosterone

By Dr. Dimitar Marinov

medical reviewed by Best HGH Doctors and Clinics dedicated team.

Evidence basedThis article is reviewed by medical professionals for the relevancy and accuracy of the content. Every article is evidence-based and contains references to peer-reviewed studies and academic research.

The human growth hormone (HGH) and testosterone (T) are two of the main hormones that regulate metabolism and energy levels, especially in men.

Yet, these two hormones are also commonly associated with hormone imbalances which can wreak havoc on your physical and mental health.

In such cases, taking exogenous hormones in the form of TRT (testosterone replacement therapy) and HGH therapy will significantly improve your symptoms and improve your overall health.

Some people may consider using both HGH and testosterone therapy together as a way to improve their results and minimize potential adverse effects.

While there is no clear consensus on whether combining HGH and testosterone therapy reduces or increases the overall risk of side effects, the combination tends to show great effectiveness according to the latest research.

It’s important to note that combining these therapies should only be done under the close supervision of a qualified healthcare provider. The potential benefits and risks of HGH and testosterone therapy stack must be carefully weighed for each individual case.

What’s the difference between HGH and testosterone hormones?

HGH and testosterone are anabolic hormones that induce favorable changes in body composition such as increased lean mass and fat loss. Yet, there are major differences between the two.

Testosterone is a steroid hormone produced by peripheral glands such as the testes which are under regulation by the pituitary. When administered exogenously, testosterone triggers a negative feedback loop that suppresses the function of the peripheral glands.

Similarly to all steroid hormones, testosterone possesses a fat-soluble structure derived from cholesterol. More specifically, testosterone is an androgen, which is a group of steroid hormones with potent anabolic and masculinizing effects.

These hormones are often labeled simply as steroids, especially in the context of performance-enhancing drugs (PEDs).

HGH and testosterone differences

On the other hand, human growth hormone is not a steroid, despite its potential use as a PED. Instead, it has a peptide (protein) structure which means it’s made of amino acids.

The different structure is one of the main differences between HGH and steroids. Furthermore, the growth hormone is produced by the pituitary, and administering it exogenously does not suppress the function of the endocrine system.

HGH and T also differ in terms of age-related changes in their levels, mechanism of action, diurnal levels, effects and side effects.

Testosterone exerts its anabolic effects directly by interacting with the androgen receptors inside the nuclei of cells such as muscle and fat cells. Testosterone production is neglectable during childhood and increases during puberty. It peaks around early adulthood and then starts to slowly decrease after the age of 30.

Testosterone is produced continuously by the testes and its levels follow a diurnal pattern that peaks around early morning.

In contrast, HGH exerts its anabolic effects indirectly, by stimulating the synthesis of IGF-1 in tissues. Its levels are highest during childhood and reach a peak during puberty. Then GH levels slowly decrease as you age.

Growth hormone has a pulsatile secretion and its levels can be undetectable in between the pulses. Furthermore, the most notable HGH spikes occur during the night.

Does HGH increase testosterone levels?

There isn’t any clinical research to suggest that HGH can increase testosterone levels. Currently, only limited evidence from in vitro studies suggests a potential positive interaction between HGH and testosterone production.

Can HGH injections increase testosterone levels?

Since these results haven’t been replicated in humans, HGH is unlikely to have any direct effect whether positive or negative. In fact, most clinical research reports no effect at all.

Therefore, growth hormone cannot be used for threatening conditions related to low T such as hypogonadism.

Instead, HGH may have an indirect effect on testosterone synthesis in people with obesity, since the hormone can reduce visceral fat and improve the function of the testes in otherwise healthy individuals.

Weight loss in general can result in improved total and free T levels amongst obese individuals. However, it’s important to note that the participants in one study had to lose at least 15% of body weight in order to significantly improve their T levels. Also, total T levels improved to a greater extent than free testosterone.

Despite the fact that HGH cannot help treat low T, it may still have some benefits that are similar to those observed during TRT, such as reducing muscle loss, stimulating fat reduction, boosting energy levels, and improving bone mineral density.

Similarly to testosterone, GH also plays a role in sexual maturation and development in boys throughout childhood and adolescence. Studies show that boys with congenital GHD develop micropenis if left without HGH therapy.

Currently, there is preliminary research suggesting HGH therapy may affect penis size during adulthood as well, but the evidence is scarce.

Can you stack HGH and testosterone for better results?

If you are suffering from a combination of growth hormone deficiency (GHD) and hypogonadism, the best way to manage your symptoms is to take a combination of TRT and HGH therapy.

Patients who are diagnosed with both conditions can receive the therapies simultaneously. Combining therapies is legal when they are prescribed by a medical doctor and used appropriately.

How effective is a stack of HGH and testosterone?

If you have both conditions but choose to receive only one of the therapies, it will most likely be ineffective in helping you manage all your symptoms.

The only way to know if you need one or both therapies is to visit a medical specialist. In most cases, you will need to undergo testing and evaluation to determine if you are a suitable candidate for TRT and HGH therapy.

These tests may include blood work to measure hormone levels, provocation tests, physical examinations, and medical histories. Once the healthcare provider has determined if you are a good candidate for these therapies, they will provide you with a testosterone or HGH prescription and monitor your progress closely.

Overall, studies suggest that stacking two therapies can lead to significant improvement in muscle mass, physical performance, and fat loss.

What’s the proper dosage for HGH and testosterone stack?

One trial in 74 men reported that a combination of 200 mg of testosterone enanthate per week and 20 µg/kg of HGH taken every other day led to almost 7% higher strength and over 8% increase in aerobic capacity in 6 months.

Keep in mind that the dosage of each therapy will depend on the severity of your condition, and it will be determined by your healthcare provider. It’s important to never adjust the dosage without consulting with your healthcare provider.

It’s important to note that the combination of TRT and HGH therapy may also increase the number of side effects

Depending on the dosage, you may experience a combination of increased water retention due to GH and increased red blood cell count related to the use of testosterone.

What results to expect from combined HGH and testosterone?

Neither HGH nor TRT given in isolation led to significant improvements in muscle strength and endurance. Instead, therapies alone resulted in increased lean mass and body fat loss, but the combined treatment had the highest effectiveness.

Similar studies in men confirm these results and report that both therapies alone or in combination lead to improved quality of life and mood levels, measured via two separate questionnaires.

The mood improvement was most significant in the HGH group, while the TRT group experienced the greatest improvement in quality of life compared to baseline.

Furthermore, the timeframe for results varies for every patient. Generally, you may start seeing results from TRT within 3-4 weeks and results from HGH therapy within 1-2 months.

As previously noted, combining the two treatments can make some of the benefits more noticeable, such as an increase in lean mass, energy levels, and fat loss – particularly around the waist. It may also speed up bone mineral density.

What brands of HGH and testosterone are best to stack?

When it comes to the best brands of HGH and testosterone medications for combined therapy, any FDA-approved brand is equally safe and effective. FDA-approved brands for HGH therapy include Humatrope, Saizen, Norditropin, Omnitrope, and Gonadotropin.

TRT is available as brand names but also generic medications such as testosterone enanthate, testosterone cypionate and testosterone undecanoate.

How to get optimal HGH and testosterone levels?

The most effective ways to naturally increase HGH and testosterone levels revolve primarily around lifestyle changes. The essential ones include optimizing your physical activity, nutrition and sleep.


Sleep is arguably the most important of the three. Having sufficient quality and quantity of sleep is essential for the normal production of both hormones as they are primarily secreted during sleep or during the early morning hours.

For example, sleep is also critical for growth hormone secretion, and research conducted on individuals with chronic insomnia demonstrates that the majority of affected people experience blunted HGH spikes during sleep.

Scientists also report that every hour of missed sleep that shortens your total sleep time to less than 7 hours can decrease total T levels by 15% in otherwise healthy individuals.

Physical activity

Optimizing your physical activity can also help maximize your natural GH and T synthesis. One of the main reasons is that regular exercise can help you burn more calories and maintain healthy body weight.

However, studies suggest that different types of physical activity may also have different effects on your hormonal health. Overall, scientists report that high-intensity anaerobic training tends to be superior compared to low-intensity cardio exercises.

According to one trial in men, high-intensity interval training (HIIT) is better than training with weights and far superior than cardio for maximizing HGH synthesis. On the other hand, the research shows that weight training was most optimal for T levels.


Your nutrition also plays a major role in ensuring that your endocrine system functions normally and produces enough growth hormone and testosterone.

Maintaining a healthy hormonal balance is vital for optimal hormonal health, and nutrition plays a significant role in achieving this.

Both too high and too low body weight can wreak havoc on T levels. That’s why men should focus on consuming an adequate amount of calories to maintain their body fat percentage in the healthy range between 8-19%.

Testosterone synthesis also requires adequate levels of healthy dietary fats, carbohydrates and minerals such as zinc.

Furthermore, obesity reduces GH pulse frequency and blunts its anabolic effects by decreasing IGF-1 levels as well. The research shows that in such cases, losing excessive weight restores normal hormone secretion.

Although certain diets such as intermittent fasting, and also many dietary supplements are purported to boost T and GH levels as well, the evidence of their effectiveness remains mixed at best.

For example, intermittent fasting and fasting, in general, can increase the frequency and amplitude of HGH peaks, but ultimately decreases the sensitivity of the growth hormone receptors, leading to decreased IGF-1 levels and reduced anabolic effects.