Melatonin During a Bulk: Does It Make Sense
Melatonin is sometimes advised during a bulk as a means for “anabolic sleep” and raising growth hormone. The editorial team checked what lies behind these claims, how lack of sleep affects the muscles and in which situations melatonin really does make sense during mass gain.
Where the idea of melatonin “for mass” comes from
Melatonin is usually associated with sleep and jet lag, but in bodybuilding communities the idea of taking it during a mass-gaining phase too sometimes comes up. The arguments vary: “melatonin raises growth hormone,” “deeper sleep means more anabolism,” “the antioxidant speeds up recovery.”
Each of these claims has partial grounds, but between “raises a certain indicator in the laboratory” and “helps gain more muscle” there is a great distance. The editorial team examined the arguments separately.
It should be stated right away: studies in which melatonin was given to people on a long-term strength-training program and muscle mass gain was measured as the main outcome are practically nonexistent. So the discussion is about logical reasoning and indirect data.
By contrast, the link between sleep quality and recovery is well substantiated. It is exactly here that melatonin can make sense — but not for everyone.
Melatonin and growth hormone
The claim about growth hormone (GH) usually refers to a study by Nassar and colleagues (2007). In it, young men and women took a single dose of melatonin or placebo before strength training; the authors reported higher GH concentrations in the melatonin group.
However, several caveats matter here. First, this is a single acute measurement, not a long-term study. Second, short-term fluctuations of GH after training within the physiological norm poorly predict muscle mass gain — this was shown, in particular, by the studies of Stuart Phillips’s group.
Third, GH in adults acts on the muscles primarily through IGF-1 and its effect on connective tissue and fat metabolism. Even the pharmacological administration of GH to healthy adults, according to clinical studies, has little effect on skeletal muscle strength.
So the argument “melatonin raises GH, therefore it will help gain mass” is an excessive oversimplification. An interesting physiological observation does not equal practical benefit for hypertrophy.
Sleep as part of the anabolic environment
Far more convincing data concern the effect of sleep deprivation on the muscles. In a study by Lamon and colleagues (2021) one night of complete sleep deprivation reduced muscle protein synthesis in young adults, raised cortisol levels and lowered testosterone.
Dattilo and colleagues (2011) put forward the hypothesis that chronic sleep deprivation creates a catabolic hormonal environment that hampers muscle recovery after damage. The hypothesis has a logical basis, though long-term controlled studies are lacking.
From this follows a practical conclusion: for gaining mass it is important not to “raise” melatonin but to ensure adequate duration and regularity of sleep. If sleep is already normal, melatonin will not make it “more anabolic.”
The consensus on athletes’ sleep (Walsh and colleagues, 2021) recommends treating sleep as a training variable on a par with load and nutrition. For an athlete on a bulk this applies no less than for an athlete cutting.
When melatonin during a bulk can make sense
The editorial team identifies several situations in which melatonin is logical to consider during a bulk too:
- late evening workouts, after which it is hard to fall asleep at the usual time;
- shift work or an irregular schedule that shifts the circadian rhythm;
- flights across several time zones — to a training camp, competitions or on a business trip;
- a temporary shift of the regimen that needs to be “put back in place.”
In all these cases melatonin works as a chronobiotic — a signal for the biological clock. It does not raise anabolism directly, but it helps restore normal sleep, on which recovery depends.
| Mass-gain factor | Evidence | The role of melatonin |
|---|---|---|
| Progressive strength training | High | None |
| Adequate protein and a caloric surplus | High | None |
| Creatine monohydrate | High | None |
| Regular sleep of adequate duration | High for recovery | Auxiliary — only when the rhythm is disrupted |
| Acute fluctuations of GH | Weak as a predictor of hypertrophy | Has no practical significance |
The table shows that melatonin is far from being in first place. If sleep is not disrupted, taking it during a bulk has no justification.
Antioxidant effects and safety
Melatonin has antioxidant properties, which are often cited as an argument in favor of recovery. However, regarding antioxidants in sport there is an important nuance: some studies with high doses of vitamins C and E showed a possible blunting of training adaptations, since reactive oxygen species are part of the signal to adapt.
Whether this applies to melatonin in ordinary doses is unknown. But the very fact is a reminder: “more antioxidants means better recovery” is not a universal rule.
As for safety, melatonin is generally well tolerated. Possible are morning drowsiness, headache, dizziness. It enhances the action of alcohol and sedatives, interacts with fluvoxamine, and estrogens increase its concentrations. Taken together with a large carbohydrate dinner it may worsen glucose tolerance.
Melatonin is not banned by WADA, but athletes should choose products with independent certification because of the risk of supplement contamination.
Editorial conclusions
There is no direct evidence that melatonin helps gain muscle mass. The argument about growth hormone relies on short-term changes that are poorly linked to hypertrophy.
At the same time, sleep is an important factor of recovery, and lack of sleep reduces muscle protein synthesis. So melatonin can be appropriate when the sleep rhythm is disrupted by late workouts, shift work or flights.
If sleep is fine, the budget is better directed to the basics: protein, calories, creatine and a quality program.
The editorial team also recommends our articles “Melatonin while cutting: does it help,” “Phosphatidylserine during a bulk: does it make sense” and “Melatonin and sleep.”
References
- Nassar E, Mulligan C, Taylor L, et al. Effects of a single dose of N-acetyl-5-methoxytryptamine (melatonin) and resistance exercise on the growth hormone/IGF-1 axis in young males and females. J Int Soc Sports Nutr. 2007;4:14.
- Lamon S, Morabito A, Arentson-Lantz E, et al. The effect of acute sleep deprivation on skeletal muscle protein synthesis and the hormonal environment. Physiol Rep. 2021;9(1):e14660.
- Dattilo M, Antunes HK, Medeiros A, et al. Sleep and muscle recovery: endocrinological and molecular basis for a new and promising hypothesis. Med Hypotheses. 2011;77(2):220–222.
- West DW, Phillips SM. Associations of exercise-induced hormone profiles and gains in strength and hypertrophy in a large cohort after weight training. Eur J Appl Physiol. 2012;112(7):2693–2702.
- Walsh NP, Halson SL, Sargent C, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2021;55(7):356–368.
- Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
- Zisapel N. New perspectives on the role of melatonin in human sleep, circadian rhythms and their regulation. Br J Pharmacol. 2018;175(16):3190–3199.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
