Growth hormone is one of the most important hormones your body produces, and its natural decline with age is one of the reasons muscle mass shrinks, body fat accumulates, recovery slows down, and skin loses its elasticity as you get older. Synthetic growth hormone injections exist, but they're expensive, require a prescription, and come with a list of potential side effects that would make anyone pause.
What if there were a way to trigger a massive, natural surge in growth hormone production using nothing more than heat? That's exactly what decades of peer-reviewed research on sauna bathing have demonstrated. The data is striking: specific sauna protocols have been shown to increase circulating growth hormone levels by as much as 16-fold — a 1,600% increase — without a single injection.
This article breaks down the science behind the sauna-growth hormone connection, the specific studies that established it, the exact protocols researchers used, and how to apply this knowledge in your own sauna practice at home.
What Is Growth Hormone and Why Does It Matter?
Human growth hormone (HGH), also known as somatotropin, is a peptide hormone produced by the pituitary gland at the base of the brain. During childhood and adolescence, it drives linear growth — the reason it carries the name "growth" hormone. But its role doesn't end when you stop getting taller. In adults, growth hormone remains essential for maintaining lean muscle mass, regulating body fat distribution, supporting bone mineral density, promoting tissue repair and recovery from injury, and sustaining healthy metabolic function.
Growth hormone doesn't act alone. When released into the bloodstream, it stimulates the liver to produce insulin-like growth factor 1 (IGF-1), which mediates many of its downstream effects on tissue growth and repair. Together, the GH-IGF-1 axis governs much of what we think of as "youthful" physiology — the ability to build muscle, recover quickly, stay lean, and maintain energy.
Here's the problem: growth hormone production peaks during puberty and begins declining steadily in your 30s. Research suggests the body produces roughly 14% less growth hormone every decade after age 30. By middle age, many people are producing a fraction of the growth hormone they had in their twenties. This decline is closely linked to age-related muscle loss (sarcopenia), increased visceral fat, slower wound healing, and reduced exercise capacity — the hallmarks of biological aging.
This is precisely why the discovery that sauna bathing can provoke dramatic spikes in growth hormone has attracted so much attention from researchers, athletes, biohackers, and anyone interested in slowing the aging process naturally.
The Research: How Sauna Use Increases Growth Hormone
The relationship between heat exposure and growth hormone release has been studied since the 1970s, but several landmark studies have defined what we know today.
The 1986 Leppäluoto Study — The 16-Fold Increase
The study that put sauna and growth hormone on the map was published in Acta Physiologica Scandinavica by Leppäluoto and colleagues in 1986. Ten healthy men and seven healthy women were exposed to dry heat in a Finnish sauna at 80°C (176°F) for one hour, twice per day, over seven consecutive days. Researchers measured a wide panel of hormones throughout the experiment.
The results were remarkable. On day one, the male participants showed a 16-fold increase in serum growth hormone levels. Prolactin also rose — 2.3-fold in men and over four-fold in women. Cortisol and ACTH actually decreased by the end of the experiment, while testosterone, thyroid hormones, and gonadotropins remained largely unchanged.
However, and this is an important detail that many articles on this topic gloss over, the growth hormone response diminished with repeated daily exposure. By day three, the spike was roughly one-third of what it was on day one — still significant, but the body was clearly adapting to the heat stress. By day seven, the response was further reduced. This attenuation effect has major implications for how you should structure sauna use if growth hormone is your goal, which we'll cover in the protocol section below.
The Two-Session and Five-Fold Studies
Other research has examined shorter, more practical sauna protocols. A study published in the Journal of Clinical Endocrinology & Metabolism found that two 20-minute sauna sessions at 80°C (176°F), separated by a 30-minute cooling period, produced a two-fold increase in growth hormone above baseline levels. A separate study using two 15-minute sessions at a higher temperature of 100°C (212°F), also with a 30-minute rest between sessions, yielded a five-fold increase. The pattern is clear: higher temperatures and longer exposure produce larger growth hormone responses.
The Age Factor
A study published in the Journal of Clinical Endocrinology & Metabolism examined the growth hormone response to sauna heat in two age groups: men aged 31–46 and men aged 49–66. After 15 minutes of Finnish sauna exposure at 72°C (162°F), the younger men showed a statistically significant increase in both growth hormone and growth hormone-releasing hormone (GHRH) in plasma. The older men did not show a significant increase in either marker.
This finding is worth sitting with. The age group that arguably needs the growth hormone boost the most — older adults experiencing age-related decline — appears to have a blunted hormonal response to standard sauna exposure. That doesn't mean sauna is useless for older adults; the cardiovascular, cognitive, and longevity benefits remain substantial regardless of age. But it does suggest that more aggressive protocols (higher temperatures, longer sessions, stricter fasting beforehand) may be needed for older individuals to achieve meaningful growth hormone stimulation.
The Mechanism: How Heat Triggers Growth Hormone Release
Understanding why heat increases growth hormone helps explain how to optimize the effect. Several interconnected physiological pathways are at work.
When your body is exposed to intense heat, core temperature rises and triggers a systemic stress response. The hypothalamus — the brain region that regulates hormonal output — detects this thermal stress and increases its production of growth hormone-releasing hormone (GHRH). GHRH then signals the anterior pituitary gland to secrete more growth hormone into the bloodstream.
At the cellular level, heat stress activates a family of protective molecules called heat shock proteins (HSPs), particularly HSP70 and HSP90. These proteins serve as molecular chaperones, helping to repair misfolded proteins and protect cells from damage. The activation of heat shock proteins sends additional stress signals to the pituitary gland, further amplifying growth hormone release. Heat shock proteins also play direct roles in muscle preservation by inhibiting protein degradation pathways, which means sauna exposure may help protect lean mass through both hormonal and cellular mechanisms simultaneously.
There's also an indirect mechanism worth noting. Sauna use increases norepinephrine levels by 200–500%, and elevated norepinephrine further stimulates growth hormone secretion. The combined effect of direct hypothalamic signaling, heat shock protein activation, and catecholamine release creates a multi-pathway stimulus for growth hormone production that is difficult to replicate with any single intervention other than intense exercise.
The Sauna Protocol for Maximum Growth Hormone Release
Not all sauna sessions produce the same hormonal response. The research points to a very specific protocol that maximizes growth hormone output, and it looks quite different from how most people typically use a sauna for general health.
Temperature
The sauna needs to reach 80–100°C (176–212°F). This is the range used in virtually all of the growth hormone studies. A traditional Finnish sauna with a quality electric sauna heater is the most straightforward way to achieve and sustain these temperatures. The heat must be intense enough to raise your core body temperature significantly and produce real physiological discomfort — that stress response is what drives the hormonal cascade.
Session Structure
The protocol that produced the 16-fold increase involved four 30-minute sauna sessions in a single day, with cooling periods between each session. A more accessible variation that still produces robust results is two sessions of 20–30 minutes separated by a 5–30 minute cooling period. The key principle is multiple rounds of heat exposure with rest between them, rather than one long continuous session. This intermittent approach appears to generate a larger cumulative hormonal response.
Frequency
This is where the growth hormone protocol diverges sharply from general health recommendations. For cardiovascular and longevity benefits, research supports frequent sauna use — ideally four to seven sessions per week. For growth hormone, the opposite is true. Because the body adapts to repeated heat exposure and the hormonal response diminishes with each consecutive day, the protocol works best when used infrequently: once per week or even once every 10 days. Save your intense, multi-round growth hormone sessions for one dedicated day per week, and use your other sauna sessions for the many other benefits heat therapy provides.
Fasting State
Blood glucose levels directly regulate growth hormone secretion. When blood sugar is elevated — for example, after a meal — the pituitary gland suppresses growth hormone release. When blood glucose is low, the brake comes off and growth hormone can surge freely. This is the same mechanism that makes deep sleep (when you're naturally fasted) the body's primary time for growth hormone secretion.
To take advantage of this, use the sauna in a semi-fasted state: avoid eating for at least two to three hours before your session. You don't need to do a prolonged fast — simply skipping the pre-sauna snack and entering your session with low circulating insulin is enough to meaningfully amplify the growth hormone response.
Cold Exposure Between Rounds
Alternating sauna heat with cold exposure during rest periods — a practice known as contrast therapy — may further enhance the hormonal response. The rapid shift from vasodilation to vasoconstriction amplifies the body's stress response and adds an additional stimulus to the hypothalamic-pituitary axis. A cold plunge tub is the most effective tool for this, though a cold shower works as well. The practice of hot-cold cycling has deep roots in Finnish and Scandinavian sauna culture and is increasingly supported by modern research for recovery, circulation, and hormonal health.
Hydration
Extended sauna sessions produce significant fluid loss through sweat. A general guideline is to drink at least 16 ounces of water for every 10 minutes you spend in the sauna. For a protocol involving two hours of total sauna time in a day, that's a considerable amount of fluid. Electrolyte replenishment matters too — sodium, potassium, and magnesium are all lost in sweat and should be replaced, especially during longer or more intense sessions.
Putting It All Together: A Sample Weekly Schedule
Here's how to integrate a growth hormone–focused protocol into a broader sauna practice without giving up the other benefits of regular heat exposure:
Monday, Wednesday, Friday (or any 3 days): General health sauna sessions. 15–20 minutes per round, 2–3 rounds, at 80–100°C. This frequency supports cardiovascular health, mood, stress reduction, and longevity based on the Finnish cohort data.
Saturday (or one dedicated day): Growth hormone protocol. Four 30-minute sauna sessions at 80–100°C with 5-minute cool-down periods between rounds (cold plunge or cold shower). Enter in a semi-fasted state — no food for 2–3 hours prior. Space the first two rounds and the second two rounds a few hours apart if possible. This is a demanding session, so plan for it, stay hydrated, and listen to your body.
By keeping the intense growth hormone sessions to once per week and maintaining general-purpose sessions on other days, you avoid the adaptation that blunts the hormonal response while still capturing the full spectrum of sauna benefits.
Which Type of Sauna Is Best for Growth Hormone?
The overwhelming majority of growth hormone research has been conducted in traditional dry Finnish saunas at temperatures between 80–100°C (176–212°F). This is important context because not all sauna types reach this threshold.
Traditional saunas — whether electric-heated or wood-fired — are the gold standard for this purpose. They reliably achieve the high temperatures required to trigger a robust hormonal response. An outdoor sauna with a properly sized heater, or an indoor traditional sauna, will give you the exact conditions used in the published research. If you're building or buying a sauna and growth hormone optimization is a priority, traditional heating is the way to go.
Infrared saunas operate at significantly lower air temperatures, typically 120–150°F (49–65°C). While infrared saunas offer well-documented benefits for pain relief, relaxation, detoxification, and cardiovascular health, they do not reach the temperature threshold that the growth hormone studies used. That said, infrared heat penetrates deeper into tissue and does raise core body temperature — so some degree of growth hormone stimulation likely occurs, though the magnitude is expected to be lower than what traditional saunas produce. If you already own an infrared sauna and want to maximize its hormonal impact, extend your session duration and ensure you're reaching a state of genuine thermal discomfort (elevated heart rate, heavy sweating).
Hybrid saunas — which combine a traditional heater with infrared panels — offer an interesting middle ground. You can use the traditional heater to reach the high air temperatures needed for the growth hormone protocol, then switch to infrared on other days for a gentler, more comfortable recovery session. For a deeper comparison of these technologies, our guide on infrared vs. traditional saunas covers every meaningful difference.
Growth Hormone Beyond the Sauna: Synergistic Lifestyle Factors
Sauna use is one of the most powerful natural growth hormone stimulators available, but it doesn't exist in a vacuum. Several other lifestyle factors influence growth hormone production, and combining them intelligently can amplify your results.
Sleep. The largest pulse of daily growth hormone secretion occurs during deep (slow-wave) sleep, typically within the first 90 minutes of falling asleep. Poor sleep quality, insufficient sleep duration, and late-night eating all suppress this nocturnal GH pulse. Interestingly, using the sauna in the late afternoon or early evening may improve sleep quality by leveraging your body's natural thermoregulatory cooling process — as your core temperature drops after a sauna session, it mimics the cooling signal that triggers sleep onset.
Exercise. Resistance training and high-intensity interval training both stimulate growth hormone release. When exercise and heat exposure are combined, studies have shown a synergistic effect — the combined growth hormone response exceeds what either stimulus produces alone. Timing your sauna session after a workout can capitalize on this synergy.
Fasting. As discussed, low insulin and blood glucose levels permit greater growth hormone release. Intermittent fasting protocols — such as a simple 16/8 eating window — naturally create periods of low insulin that align well with sauna use. Scheduling your growth hormone sauna session near the end of a fasting window, before your first meal, may produce the strongest combined effect.
Body composition. Excess body fat, particularly visceral fat, is associated with lower baseline growth hormone levels. Individuals with higher body fat percentages tend to have blunted growth hormone responses to various stimuli, including exercise and heat. Maintaining a healthy body composition supports stronger hormonal output from sauna sessions and everything else.
Combining Sauna With Red Light Therapy and Cold Exposure
Many home sauna owners are now layering multiple recovery modalities into a single session. Combining sauna heat with red light therapy and cold plunge immersion creates what some wellness practitioners call a "contrast plus photobiomodulation" protocol. While the research on this specific combination is still emerging, each individual component has independent scientific support.
Red light therapy at wavelengths of 630–660nm (visible red) and 810–850nm (near-infrared) has been studied for its effects on mitochondrial function, collagen production, muscle recovery, and inflammation reduction. Several sauna models with built-in red light therapy panels are now available that allow you to receive both treatments simultaneously.
Cold exposure following sauna use stimulates norepinephrine release, constricts blood vessels to reduce inflammation, and — as noted above — may further enhance the growth hormone response through additional stress signaling to the hypothalamic-pituitary axis. Our full cold plunge collection includes options ranging from simple immersion tubs to temperature-controlled units with chillers for precise cold therapy.
Safety Considerations
The growth hormone sauna protocol is more demanding than a typical sauna session. Four 30-minute rounds at high temperatures in a single day requires genuine physical resilience and careful attention to hydration and recovery. Keep the following in mind:
If you're new to sauna use, build up gradually. Start with shorter sessions at moderate temperatures and increase over weeks as your heat tolerance improves. Jumping straight into a two-hour protocol is not advisable for beginners.
Pregnant women and children under 16 should not use high-temperature saunas. Individuals with cardiovascular disease, uncontrolled blood pressure, or any chronic medical condition should consult their physician before undertaking an intensive sauna protocol.
Men who are actively trying to conceive should be aware that repeated exposure to high scrotal temperatures can temporarily reduce sperm production. This effect typically reverses within 45–60 days of stopping regular heat exposure, but it's worth noting if fertility is a near-term concern.
Never use the sauna under the influence of alcohol. Dehydration and impaired thermoregulation from alcohol dramatically increase the risk of hyperthermia, fainting, and cardiac events.
Listen to your body. Dizziness, nausea, rapid or irregular heartbeat, and confusion are signs that you've pushed too far. Exit the sauna immediately, cool down, and hydrate if you experience any of these symptoms.
The Bottom Line
The science linking sauna use to growth hormone release is well-established and spans decades of peer-reviewed research. Heat exposure at 80–100°C triggers a cascade of physiological responses — from hypothalamic activation and heat shock protein expression to catecholamine release — that collectively drive significant increases in circulating growth hormone. The most dramatic responses (up to a 16-fold increase) come from intensive, multi-session protocols performed infrequently and in a fasted state.
For anyone interested in natural strategies to support muscle maintenance, fat metabolism, recovery, and healthy aging, adding a deliberate growth hormone protocol to your sauna routine is one of the most evidence-backed tools available. And with a quality traditional sauna at home, you can implement these protocols on your own schedule, week after week, without the cost or complexity of clinical interventions.
If you're still deciding which sauna type best fits your goals, space, and budget, our complete sauna pricing guide breaks down real costs across every category, and our team is available at (360) 233-2867 to help you find the right fit.
Haven Of Heat and its affiliates do not provide medical advice. All content published on this website is for general informational and educational purposes only and should not be relied upon as a substitute for advice from qualified professionals. Always consult a licensed medical provider regarding health-related questions.
References
- Leppäluoto J, Huttunen P, Hirvonen J, Väänänen A, Tuominen M, Vuori J. Endocrine effects of repeated sauna bathing. Acta Physiologica Scandinavica. 1986;128(3):467-470.
- Kukkonen-Harjula K, Oja P, Laustiola K, et al. Haemodynamic and hormonal responses to heat exposure in a Finnish sauna bath. European Journal of Applied Physiology. 1989;58(5):543-550.
- Vuori I. Sauna bather's circulation. Annals of Clinical Research. 1988;20(4):249-256.
- Huhtaniemi IT, Laukkanen JA. Endocrine effects of sauna bath. Current Opinion in Endocrine and Metabolic Research. 2020;11:15-20.
- Ftaiti F, et al. Effect of hyperthermia and physical activity on circulating growth hormone. Applied Physiology, Nutrition, and Metabolism. 2008;33(5):880-887.
Leave a comment