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Cited by 24Hypothalamic control of reproductive hormonesHormonal and reproductive studiesRegulation of Appetite and Obesity

The DOI matches its Crossref record; 72 of the 72 references it cites were found in a registry or an index; none of the 98 sources its claims cite is checked for support yet.

Dysregulation of the Hypothalamic-Pituitary-Testicular Axis due to Energy Deficit

Open access
Grossmann, Mathis, Wittert, Gary A·2021·The Journal of Clinical Endocrinology & Metabolism

Abstract

Context: Although gonadal axis dysregulation from energy deficit is well recognized in women, the effects of energy deficit on the male gonadal axis have received much less attention. Evidence acquisition: To identify relevant articles, we conducted PubMed searches from inception to May 2021. Evidence synthesis: Case series and mechanistic studies demonstrate that energy deficit (both acutely over days or chronically over months) either from inadequate energy intake and/or excessive energy expenditure can lower serum testosterone concentration as a result of hypothalamic-pituitary-testicular (HPT) axis dysregulation in men. The extent to which this has clinical consequences that can be disentangled from the effects of nutritional insufficiency, concomitant endocrine dysregulation (eg, adrenal and thyroid axis), and coexisting comorbidities (eg, depression and substance abuse) is uncertain. HPT axis dysfunction is primarily the result of loss of GnRH pulsatility resulting from a failure of leptin to induce kisspeptin signaling. The roles of neuroendocrine consequences of depression, hypothalamic-pituitary-adrenal axis activation, proinflammatory cytokines, Ghrelin, and genetic susceptibility remain unclear. In contrast to hypogonadism from organic pathology of the HPT axis, energy deficit-associated HPT dysregulation is functional, and generally reversible by restoring energy balance. Conclusions: The clinical management of such men should aim to restore adequate nutrition and achieve and maintain a healthy body weight. Psychosocial comorbidities must be identified and addressed. There is no evidence that testosterone treatment is beneficial. Many knowledge gaps regarding epidemiology, pathophysiology, and treatment remain and we highlight several areas that require future research.

Overview

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TL;DR

This minireview synthesizes evidence that energy deficit—from inadequate intake and/or excessive exercise—suppresses the male hypothalamic-pituitary-testicular (HPT) axis, primarily via loss of GnRH pulsatility from failure of leptin to induce kisspeptin signaling. The resulting hypogonadism is functional and generally reversible with restoration of energy balance, and testosterone treatment is not recommended.

Key findings

  • Acute fasting (water only) in healthy young men reduced total testosterone from 13.8 nmol/L to 10.9 nmol/L and LH from 2.9 to 1.1 IU/L within 48 hours; 3–5 days of fasting lowered total and free testosterone by 50% and LH by 30%, changes completely prevented by pulsatile GnRH infusion. Older men (mean age 67) showed no significant fasting-associated changes, whereas young men (mean age 28) fell 46% (total) and 40% (free) testosterone.
  • Chronic energy deficit: an early series of 28 Indian men with severe protein-calorie malnutrition had total testosterone reduced ~50%; a case-control study of 31 men with anorexia nervosa (BMI 15.8 kg/m²) had total testosterone 9.2 nmol/L vs 23.5 nmol/L in controls. In the CALERIE 2-year, 25% caloric-restriction RCT, men (n = 66) showed no difference in total testosterone or LH, but higher SHBG and lower calculated free testosterone at 12 months (between-group difference 100 pmol/L [2.89 ng/dL]), with improved sexual drive and arousal.
  • Exercise: serum testosterone fell 60% after a marathon, and −67% ± 18% after a 1230-km ultra-endurance cycling event; men running ≥64 km/week had ~20% lower total and ~30% lower free testosterone than sedentary controls. In US Army Ranger training with 8% weight loss, testosterone decreased ~70%, recovering within 2–6 weeks; in another cohort testosterone fell from 16.3 to 2.2 nmol/L but recovered promptly with refeeding despite ongoing stressors.
  • Mechanisms: leptin replacement during 72-hour fasting prevented starvation-induced HPT changes; ghrelin administration reduced LH pulse amplitude and frequency and lowered testosterone; IL-2 infusion suppressed testosterone secretion more markedly in younger than older men. Testosterone treatment during a 28-day energy deficit increased lean mass by 2.5 kg (95% CI, 1.6–3.3) but had no effect on muscle function, and there is no evidence it improves clinically important outcomes.

Methods

  • Narrative minireview; PubMed searches from inception to May 2021 to identify relevant articles.
  • Evidence synthesis drawn from case series, cross-sectional and case-control studies, randomized controlled trials, and mechanistic/preclinical studies in men and animal models.
  • No primary data were generated or analyzed (data sharing not applicable).

Limitations

  • Stated: the true population frequency of energy deficit-associated HPT dysregulation is unknown; most evidence comes from men with pronounced energy deficit, and effects of lesser deficits are unclear; the degree to which symptoms reflect HPT suppression versus comorbidities or other endocrine changes (adrenal, thyroid, GH/IGF-1) is uncertain; SHBG is commonly increased, complicating interpretation of total testosterone; effects on sperm concentration and fertility are unknown; no prospective data on management approaches or long-term health outcomes; roles of HPA-axis activation, ghrelin, and genetic susceptibility require further study.
  • Evident from the text: the literature relies heavily on convenience samples and single case reports likely representing the severe end of the spectrum, and several cited studies are small (e.g., n = 6–10 in exercise and ghrelin studies).

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Integrity signals

Registry

Crossref · 10.1210/clinem/dgab517

Cites

72 of 72 references verified0 citation errors · 0 not checkable

Statistics

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Verification

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Citations

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Metadata

Authors
Grossmann, M., & Wittert, G. A.
Affiliations
  • The University of Melbourne (AU)
  • Queen Elizabeth Hospital (AU)
Corresponding author
Grossmann, Mathis
Venue
The Journal of Clinical Endocrinology & Metabolism
Published
2021-07-15
Volume
106
Issue
12
Pages
e4861-e4871
ISSN
  • 0021-972X (ISSN-L)
  • 1945-7197
OpenAlex
W3179455916
Cited by
24
References
71
Citations by year
2026: 5 · 2025: 3 · 2024: 7 · 2023: 5 · 2022: 4
FWCI
0.58
Type
journal article
Language
en
Open access
Locations
  • The Journal of Clinical Endocrinology & Metabolism (publishedVersion)
  • PubMed (publishedVersion)
Funders
Eli Lilly and Company
Topics
  • Health Sciences › Medicine › Reproductive Medicine › Hypothalamic control of reproductive hormones
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Regulation of Appetite and Obesity
Keywords
hypothalamic-pituitary-testicular axis, negative energy balance, male hypogonadism, testosterone, GnRH pulsatility, kisspeptin, leptin signaling, depression, hypothalamic-pituitary-adrenal axis, ghrelin, inflammatory cytokines, energy balance, nutritional insufficiency
MeSH terms
Energy Metabolism, Humans, Hypogonadism, Hypothalamo-Hypophyseal System, Male, Pituitary-Adrenal System, Prognosis, Testis

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Data sources

Bibliographic data: Semantic Scholar, OpenAlex, Crossref.

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