# IGF-I

> Insulin-like Growth Factor 1 (IGF-I) is a hormone similar in molecular structure to insulin and plays a crucial role in childhood growth and continues to h

*Source: [https://www.health3.app/biomarkers/igfi](https://www.health3.app/biomarkers/igfi)*

### On This Page

- What it measures
- Measurement units
- Reference ranges
- Health impact
- Scientific references

## What is IGF-I?

Insulin-like Growth Factor 1 (IGF-I) is a hormone similar in molecular structure to insulin and plays a crucial role in childhood growth and continues to have anabolic effects in adults. It is produced primarily in the liver and stimulated by growth hormone (GH) released from the pituitary gland. IGF-I aids in promoting normal bone and tissue growth and development. In adults, it has anabolic effects, which include muscle growth, repair, and metabolism. It also influences cell growth and development, affecting various bodily functions.

**Low levels of IGF-I**, can indicate growth hormone deficiency, leading to stunted growth and delayed development. In adults, low IGF-I levels can result in decreased bone density and muscle weakness, contributing to a higher risk of osteoporosis and fractures. Lower levels of IGF-I are often observed in aging adults and can be associated with reduced muscle mass and strength, known as sarcopenia. Causes of low IGF-I can include malnutrition, hormonal imbalances, liver disease, and genetic factors affecting growth hormone production.

**Elevated levels of IGF-I** are less common and can be associated with excessive growth hormone production, as seen in conditions like acromegaly. This condition, usually due to a benign tumor in the pituitary gland, can lead to abnormal growth of the hands, feet, and face in adults. High levels of IGF-I might also contribute to insulin resistance and are being studied for their potential association with an increased risk of certain cancers, although this relationship is not yet fully understood.

Both high and low levels of IGF-1 have been associated with an increased all-cause mortality risk, with a mid-range being associated with the lowest mortality.

To **maintain healthy IGF-I levels**:

- Engage in regular physical activity and exercise, as it can help stimulate growth hormone production and, consequently, IGF-I levels.
- Ensure adequate sleep, as growth hormone is primarily released during deep sleep. Aim for 7-9 hours of quality sleep per night.
- Maintain a balanced diet rich in protein, as it is essential for the production of IGF-I and the growth and repair of tissues.
- Manage stress levels through relaxation techniques, as chronic stress can negatively impact growth hormone and IGF-I production.

## Measurement Units

IGF-I can be measured in: ng/mL, nmol/L, µg/100mL, µg/dL, µg/L, µg%

## Reference Ranges by Age and Gender

Reference ranges represent typical values for healthy individuals. Your healthcare provider must interpret your specific results.

| Age Range | Gender | Unit | Optimal | Normal | Source |
| --- | --- | --- | --- | --- | --- |
| All ages | All genders | ng/mL | - | 120 - 160 | Barati, 2022 |
| 18 - 20 | Woman | ng/mL | - | 155 - 585 | Arnoux, 2016 |
| 18 - 20 | Man | ng/mL | - | 168 - 537 | Arnoux, 2016 |
| 19 - 25 | Woman | ng/mL | - | 231 - 550 | Rifai, 2023 |
| 19 - 25 | Man | ng/mL | - | 202 - 433 | Rifai, 2023 |
| 20 - 24 | Woman | ng/mL | - | 111 - 423 | Alte, 2008 |
| 20 - 24 | Man | ng/mL | - | 156 - 385 | Alte, 2008 |
| 21 - 23 | Woman | ng/mL | - | 144 - 541 | Arnoux, 2016 |
| 21 - 23 | Man | ng/mL | - | 147 - 477 | Arnoux, 2016 |
| 24 - 26 | Woman | ng/mL | - | 134 - 501 | Arnoux, 2016 |
| 24 - 26 | Man | ng/mL | - | 132 - 430 | Arnoux, 2016 |
| 25 - 29 | Woman | ng/mL | - | 102 - 360 | Alte, 2008 |
| 25 - 85 | Woman | ng/mL | - | 135 - 449 | Rifai, 2023 |
| 25 - 85 | Man | ng/mL | - | 135 - 449 | Rifai, 2023 |
| 25 - 29 | Man | ng/mL | - | 119 - 343 | Alte, 2008 |
| 27 - 29 | Woman | ng/mL | - | 126 - 467 | Arnoux, 2016 |
| 27 - 29 | Man | ng/mL | - | 122 - 396 | Arnoux, 2016 |
| 30 - 34 | Woman | ng/mL | - | 94 - 309 | Alte, 2008 |
| 30 - 39 | Woman | ng/mL | - | 113 - 403 | Arnoux, 2016 |
| 30 - 34 | Man | ng/mL | - | 97 - 306 | Alte, 2008 |
| 30 - 39 | Man | ng/mL | - | 108 - 348 | Arnoux, 2016 |
| 35 - 39 | Woman | ng/mL | - | 86 - 271 | Alte, 2008 |
| 35 - 39 | Man | ng/mL | - | 84 - 275 | Alte, 2008 |
| 40 - 44 | Woman | ng/mL | - | 79 - 246 | Alte, 2008 |
| 40 - 49 | Woman | ng/mL | - | 97 - 331 | Arnoux, 2016 |
| 40 - 44 | Man | ng/mL | - | 76 - 251 | Alte, 2008 |
| 40 - 49 | Man | ng/mL | - | 91 - 301 | Arnoux, 2016 |
| 45 - 49 | Woman | ng/mL | - | 73 - 232 | Alte, 2008 |
| 45 - 49 | Man | ng/mL | - | 71 - 233 | Alte, 2008 |
| 50 - 54 | Woman | ng/mL | - | 68 - 228 | Alte, 2008 |
| 50 - 59 | Woman | ng/mL | - | 80 - 271 | Arnoux, 2016 |
| 50 - 59 | Man | ng/mL | - | 81 - 273 | Arnoux, 2016 |
| 50 - 54 | Man | ng/mL | - | 66 - 221 | Alte, 2008 |
| 55 - 59 | Woman | ng/mL | - | 64 - 231 | Alte, 2008 |
| 55 - 59 | Man | ng/mL | - | 61 - 214 | Alte, 2008 |
| 60 - 69 | Woman | ng/mL | - | 64 - 227 | Arnoux, 2016 |
| 60 - 64 | Woman | ng/mL | - | 61 - 237 | Alte, 2008 |
| 60 - 69 | Man | ng/mL | - | 75 - 260 | Arnoux, 2016 |
| 60 - 64 | Man | ng/mL | - | 55 - 211 | Alte, 2008 |
| 65 - 69 | Woman | ng/mL | - | 59 - 241 | Alte, 2008 |
| 65 - 69 | Man | ng/mL | - | 49 - 209 | Alte, 2008 |
| 70 - ∞ | Woman | ng/mL | - | 56 - 204 | Arnoux, 2016 |
| 70 - 74 | Woman | ng/mL | - | 57 - 237 | Alte, 2008 |
| 70 - ∞ | Man | ng/mL | - | 64 - 242 | Arnoux, 2016 |
| 70 - 74 | Man | ng/mL | - | 46 - 207 | Alte, 2008 |
| 75 - ∞ | All genders | ng/mL | - | 55 - 219 | Alte, 2008 |
| 75 - ∞ | Man | ng/mL | - | 48 - 202 | Alte, 2008 |

## Academic References

1. Rifai N.. Tietz Textbook of Laboratory Medicine (2023). *Elsevier*.
2. Alte D, Friedrich N, Kohlmann T, Lerch MM, Lüdemann J, Nauck M, Spilcke-Liss E, Völzke H, and Wallaschofski H. Reference ranges of serum IGF-1 and IGFBP-3 levels in a general adult population: results of the Study of Health in Pomerania (SHIP) (2008). *Growth Horm IGF Res*. [DOI: 10.1016/j.ghir.2007.09.005](https://doi.org/10.1016/j.ghir.2007.09.005)
3. Barati M, Bawadi H, Christensen K, Giovannucci E, Kopchick JJ, Lagani V, Laviano A, Longo VD, Mirisola MG, Montesanto A, Passarino G, Rahmani J, Vardavas R, and Zand H. Association between IGF-1 levels ranges and all-cause mortality: A meta-analysis (2022). *Aging Cell*. [DOI: 10.1111/acel.13540](https://doi.org/10.1111/acel.13540)
4. Bodine SC, Clarke BA, Glass DJ, Nunez L, Rommel C, Rossman R, Stitt TN, and Yancopoulos GD. Mediation of IGF-1-induced skeletal myotube hypertrophy by PI(3)K/Akt/mTOR and PI(3)K/Akt/GSK3 pathways (2001). *Nat Cell Biol*. [DOI: 10.1038/ncb1101-1009](https://doi.org/10.1038/ncb1101-1009)
5. Clemmons DR. Metabolic actions of insulin-like growth factor-I in normal physiology and diabetes (2012). *Endocrinol Metab Clin North Am*. [DOI: 10.1016/j.ecl.2012.04.017](https://doi.org/10.1016/j.ecl.2012.04.017)
6. Friedrich N, Jørgensen T, Juul A, Linneberg A, Spielhagen C, Thuesen B, and Wallaschofksi H. The association between IGF-I and insulin resistance: a general population study in Danish adults (2012). *Diabetes Care*. [DOI: 10.2337/dc11-1833](https://doi.org/10.2337/dc11-1833)
7. Arnoux Armelle, Brailly-Tabard Sylvie, Chanson Philippe , Massart Catherine, Mavromati Maria, Piketty Marie-Liesse, Souberbielle Jean-Claude, and Young Jacques. Reference Values for IGF-I Serum Concentrations: Comparison of Six Immunoassays (2016). *The Journal of Clinical Endocrinology & Metabolism*. [DOI: 10.1210/jc.2016-1257](https://doi.org/10.1210/jc.2016-1257)
8. Friedrich N, Jørgensen T, Juul A, Linneberg A, Spielhagen C, Thuesen B, and Wallaschofksi H. The association between IGF-I and insulin resistance: a general population study in Danish adults (2012). *Diabetes Care*. [DOI: 10.2337/dc11-1833](https://doi.org/10.2337/dc11-1833)
9. Clemmons DR. Role of insulin-like growth factor iin maintaining normal glucose homeostasis (2004). *Horm Res*. [DOI: 10.1159/000080763](https://doi.org/10.1159/000080763)

### ⚠️ Important Medical Information

This reference page is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Reference ranges vary between laboratories. Always review your lab results with a qualified healthcare provider.