Growth Hormone and Fitness: What Can Supplements

Growth Hormone and Fitness: What Can Supplements Actually Do?

Growth hormone (GH, or somatotropin) is one of the most discussed hormones in the fitness world. Promises to "boost GH levels naturally" sell supplements and training programmes. But what does the science actually say?

Who this is for: Anyone who trains and wants to know whether "GH boosters" are worth the money, and what you can genuinely do to optimise your growth hormone levels.

TL;DR

Growth hormone is a peptide hormone produced by the pituitary gland. It influences muscle protein synthesis, fat breakdown, and recovery
Most "GH booster" supplements (arginine, ornithine, GABA) raise GH temporarily, but the effect is too small and short-lived to impact body composition (Chromiak & Antonio, 2002)
Sleep is the most effective natural GH stimulator — up to 75% of daily GH is released during deep sleep (Van Cauter & Plat, 1996)
Intense resistance training raises GH significantly (Kraemer & Ratamess, 2005)
Synthetic GH injection is a prescription drug and banned in sport — it's not a supplement topic
Best results come from: quality sleep + intense training + adequate protein

What Is Growth Hormone and What Does It Do?

Growth hormone (GH) is a 191-amino acid peptide hormone secreted by the pituitary gland. Its primary functions:

Muscle synthesis: GH stimulates IGF-1 (insulin-like growth factor) production in the liver, which in turn promotes muscle protein synthesis
Fat breakdown: GH promotes lipolysis — using fat as an energy source
Recovery: Accelerates tissue repair and bone strengthening
Metabolic regulation: Influences carbohydrate and fat metabolism

GH is released in pulses — the largest spike occurs during the first hours of deep sleep. GH production declines with age: from age 30, it drops ~14% per decade (Iranmanesh et al., 1991).

Supplements That Claim to Boost GH

1. Arginine

Arginine is the most common "GH booster" ingredient. What does the science say?

Iseri et al. (2008) showed that 5-9 g of oral arginine raised resting GH levels by ~100%
BUT: Welborn et al. (2002) found that arginine taken before exercise actually reduced exercise-induced GH release
Practical effect on body composition: not demonstrated (Chromiak & Antonio, 2002)

Bottom line: Arginine raises resting GH, but the effect is temporary (30-60 min) and doesn't translate into muscle gain or fat loss.

2. Ornithine

Ornithine is an arginine metabolite marketed as a GH stimulator.

Sugino et al. (2008) showed that 400 mg/kg ornithine raised GH levels after resistance training
That is a very large dose (28 g for a 70 kg person) and can cause GI distress
At practical doses (1-3 g), the effect is minimal

3. GABA (Gamma-aminobutyric acid)

Powers et al. (2008) found that 3 g GABA raised resting GH by ~400%
However: GABA doesn't cross the blood-brain barrier well when taken orally, so the mechanism is unclear
Long-term effect on body composition is unproven

4. Melatonin

Forsling et al. (1999) showed that melatonin increases GH secretion during sleep
It works indirectly — by improving sleep quality, which in turn promotes GH production
Dose: 0.5-3 mg before bed

What Actually Works for Optimising GH

Strategy	GH effect	Evidence	Cost
7-9 h quality sleep	+++	Strong	Free
Intense resistance training	+++	Strong	Gym membership
HIIT	++	Moderate	Free
Fasting (16-24 h)	++	Moderate	Free
Arginine (5-9 g)	+ (at rest)	Moderate	~10-15/mo
GABA (3 g)	+	Weak	~8-12/mo
Melatonin (0.5-3 mg)	+ (indirect)	Moderate	~5/mo

Training Effect

Kraemer & Ratamess (2005) confirmed that intense resistance training (large muscle group exercises, short rest periods, 70-85% 1RM) raises GH significantly during and after training. This is more effective than any supplement.

Sleep Effect

Van Cauter & Plat (1996) documented that 60-75% of daily GH is released during deep sleep (N3 phase). Sleep deprivation drastically reduces GH production. If you pick one thing to improve — pick sleep.

Common Mistakes

1. Buying GH boosters before optimising sleep and training — Supplement effects are negligible compared to 8 hours of sleep and proper training.
2. Taking arginine before workouts — It may actually reduce the exercise GH response. If you use it, take it on rest days.
3. Equating GH spikes with muscle growth — A temporary GH spike (30-60 min) doesn't automatically mean more muscle. Chronic, sustained levels matter.
4. Considering illegal GH injections — A prescription drug, banned in sport, with serious side effects. Never a supplement option.

Frequently Asked Questions

Do GH booster supplements work?

They raise GH temporarily (30-60 min), but this doesn't translate to measurable muscle growth or fat loss. Optimising sleep and training is more effective.

How much does GH decline with age?

About 14% per decade from age 30 (Iranmanesh et al., 1991). This is normal and can be slowed with training, sleep, and healthy nutrition.

Does fasting raise growth hormone?

Yes, studies show that 16-24 hour fasts significantly raise GH levels (Hartman et al., 1992). This is the body's adaptation response to preserve muscle during fasting.

Does creatine affect GH levels?

Not directly. But creatine improves training intensity, which may in turn enhance the GH response to training. See our muscle growth supplement guide.

Do women need different GH optimisation strategies?

Women's GH levels are on average higher than men's, but decline similarly with age. The same strategies (sleep, training, nutrition) apply to both sexes.

Estonia Angle

"GH booster" supplements are sold in Estonia primarily through fitness stores, priced at 15-40 per month. Before buying them, make sure your sleep is solid (Estonia's long dark winters affect melatonin production — consider adding melatonin) and your training is sufficiently intense.

If you're looking for evidence-based supplements for muscle growth, look at creatine and protein instead — these are the only supplements where muscle-building effects have been repeatedly proven.

References

1. Chromiak, J.A. & Antonio, J. (2002). Use of amino acids as growth hormone-releasing agents by athletes. Nutrition, 18(7-8), 657-661.
2. Van Cauter, E. & Plat, L. (1996). Physiology of growth hormone secretion during sleep. Journal of Pediatrics, 128(5), S32-S37.
3. Kraemer, W.J. & Ratamess, N.A. (2005). Hormonal responses and adaptations to resistance exercise and training. Sports Medicine, 35(4), 339-361.
4. Iranmanesh, A., Lizarralde, G. & Veldhuis, J.D. (1991). Age and relative adiposity are specific negative determinants of the frequency and amplitude of GH secretory bursts. Journal of Clinical Endocrinology and Metabolism, 73(5), 1081-1088.
5. Sugino, T., Shirai, T., Kajimoto, Y. & Kajimoto, O. (2008). L-ornithine supplementation attenuates physical fatigue in healthy volunteers by modulating lipid and amino acid metabolism. Nutrition Research, 28(11), 738-743.
6. Powers, M.E., Yarrow, J.F., McCoy, S.C. & Borst, S.E. (2008). Growth hormone isoform responses to GABA ingestion at rest and after exercise. Medicine and Science in Sports and Exercise, 40(1), 104-110.
7. Hartman, M.L., Veldhuis, J.D., Johnson, M.L., Lee, M.M., Alberti, K.G., Samojlik, E. & Thorner, M.O. (1992). Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men. Journal of Clinical Endocrinology and Metabolism, 74(4), 757-765.

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