IGF-1 (Insulin-like Growth Factor)
IGF-1 is a liver-produced hormone induced by growth hormone that drives tissue growth and repair. It is used to screen for growth hormone deficiency or excess (acromegaly) since it is more stable than GH itself. Levels decline with age; low values can accompany frailty, and very high values have been associated with some cancers.
Units: ng/mL; some labs report nmol/L (nmol/L = ng/mL × 0.131). Check the units on your report before comparing to any range here.
Optimal range: who says what
Institutions, researchers and practitioners draw the line in different places. Each position is listed with who holds it and, where a document states it, a link. How we verify ranges.
- Institution or studyMiddle of the age-adjusted rangeCohort data show a J-curve: both low and high IGF-1 associate with higher mortalityMeta-analysis of 12 cohorts: both the 10th and the 90th IGF-1 percentiles carry higher all-cause mortality than the median
- Lab reference intervalAge-dependent, typical adult: 100-300 ng/mLWhat a lab report flags against. A lab interval is not an optimal target.
9 of 21 itemized panels
Advanced / Specialty Markers
What is IGF-1 (Insulin-like Growth Factor)?
IGF-1 is a hormone similar in structure to insulin that plays a central role in growth, development, and tissue repair. It is produced primarily by the liver in response to growth hormone (GH) stimulation. Because GH is released in pulses and hard to measure, IGF-1 is a reliable proxy for GH status.
IGF-1 promotes cell growth and proliferation throughout the body. In youth, it drives normal development. In adults, it maintains muscle mass, bone density, and tissue repair. However, the IGF-1 pathway also promotes aging and cancer risk, creating an optimization paradox.
The longevity research community debates optimal IGF-1 levels. Very low levels (seen in caloric restriction and certain genetic mutations) are associated with extended lifespan in animals. But too low in humans risks muscle loss, frailty, and cognitive decline. Context and individual goals matter.
The Growth vs Longevity Paradox
- Cancer connection: High IGF-1 associated with increased risk of several cancers (breast, prostate, colorectal)
- Longevity data: Centenarians and long-lived populations often have lower IGF-1 levels
- Muscle and bone: Low IGF-1 contributes to sarcopenia and osteoporosis with aging
- GH deficiency marker: Very low IGF-1 may indicate growth hormone deficiency requiring evaluation
- Individual optimization: Optimal level depends on age, goals, and health status
Interpretation bands (curated, PMID-backed)
Holder: OptimizeBiomarkers editorial synthesis of: Meta-analysis and dose-response metaregression: circulating insulin-like growth factor I (IGF-I) and mortality (Burgers et al., 2011); Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity (Milman et al., 2014); Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: pooled individual data analysis of 17 prospective studies (Key et al., 2010). No single paper sets these cutoffs; for attributed targets see who says what.
Balanced (Adults)100-180 ng/mL▼
- Lower-normal range balances tissue maintenance with longevity concerns
- Many longevity physicians target this range for most adults
Higher Normal180-300 ng/mL▼
- Good for muscle building and recovery but may carry increased long-term cancer risk
- Acceptable for athletes or those with specific performance goals
Low<100 ng/mL▼
- May indicate GH deficiency, malnutrition, or chronic illness
- Risk of muscle loss and cognitive decline
- Evaluate underlying cause
Elevated>300 ng/mL▼
- Increases cancer risk
- May indicate acromegaly if GH also elevated
- Pituitary tumor evaluation warranted if very high
- Meta-analysis and dose-response metaregression: circulating insulin-like growth factor I (IGF-I) and mortality.
- Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity.
- Insulin-like growth factor 1 (IGF1), IGF binding protein 3 (IGFBP3), and breast cancer risk: pooled individual data analysis of 17 prospective studies.
What raises or lowers IGF-1
Causes of high IGF-1
- Acromegaly (pituitary tumor producing GH)
- GH therapy
- High protein intake
- Obesity in adolescents
- Puberty
Causes of low IGF-1
- Aging (declines gradually with age)
- Malnutrition/caloric restriction
- Chronic illness
- Liver disease
- GH deficiency
- Hypothyroidism
- Chronic inflammation
Symptoms when IGF-1 is high or low
When high
- Acromegaly features (if very high): Enlarged hands/feet
- Facial changes
- Joint pain
- Sleep apnea
- Increased sweating
Mildly elevated IGF-1 often asymptomatic. Acromegaly symptoms develop slowly over years.
When low
- Decreased muscle mass
- Increased body fat
- Reduced exercise capacity
- Fatigue
- Poor wound healing
- Cognitive decline
- Osteoporosis risk
Symptoms overlap with normal aging. Very low IGF-1 with symptoms may warrant GH deficiency evaluation.
How to move IGF-1
Effect sizes (how much something moves the marker) appear only where the paper cited under the item states them. Talk to your clinician before starting or changing any medication or supplement.
Protein Timing and Quality
Adequate protein (0.7-1g/lb) supports IGF-1 production. Protein after exercise amplifies the anabolic response. Chronic protein restriction lowers IGF-1 (may be beneficial for longevity).
Sleep for GH Release
Growth hormone (which stimulates IGF-1) is primarily released during deep sleep. Optimize sleep quality with consistent schedule, cool dark room, and 7-9 hours duration.
Resistance Training
Heavy resistance training acutely increases GH and chronically supports healthy IGF-1 levels. Compound movements with adequate volume are most effective.
Caloric Intake Balance
Caloric restriction lowers IGF-1 (potential longevity benefit). Caloric surplus raises IGF-1 (muscle building). Choose based on current goals and health status.
Intermittent Fasting
Short-term fasting (16-24 hours) transiently decreases IGF-1 while increasing GH. May provide benefits of lower IGF-1 without chronic reduction.
When to retest
- Test fasting in morning for consistency
- IGF-1 is stable day-to-day unlike GH - single measurement usually sufficient
- If very low, check GH stimulation testing
- If very high, check GH and pituitary MRI
Scientific Evidence
IGF-1 and Breast Cancer Risk
Pooled data from 17 prospective studies (4,790 cases) found women in the highest fifth of IGF-1 had 28% higher breast cancer risk than those in the lowest fifth (OR 1.28), confined to estrogen receptor-positive tumors.
IGF-1 and Longevity
Among 184 people in their 90s, women with IGF-1 at or below the median (96 ng/mL) survived longer than those above it; no difference was seen in men. In both sexes with a history of cancer, lower IGF-1 predicted longer survival.
Source: Low insulin-like growth factor-1 level predicts survival in humans with exceptional longevity.
Low and High IGF-1 and Mortality
A meta-analysis of 12 studies (14,906 participants) found a U-shaped relationship: all-cause mortality was higher with both low IGF-1 (HR 1.27) and high IGF-1 (HR 1.18) than with mid-range levels, for both cancer and cardiovascular deaths.
Which Providers Test IGF-1 (Insulin-like Growth Factor)?
Cheapest: Superpower at $349/year. Most comprehensive: Function Health, 160+ biomarkers for $365/year.
9 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
 Superpower | $349 | 100+ | $3.49 |
| $349 | 75+ | $4.65 | |
 Function Health | $365 | 160+ | $2.28 |
| $365 | 100+ | $3.65 | |
| $495 | 80+ | $6.19 | |
| $700 | 138 | $5.07 | |
| $895 | 100+ | $8.95 | |
| $1188 | 70+ | $16.97 | |
| $1950 | 130+ | $15.00 |
$/Biomarker is annual cost divided by the panel's advertised biomarker count, not the price of this one test. We track 23 blood test providers (32 plans); 21 of those plans are itemized marker by marker. Compare all of them.
12 itemized panels do not include IGF-1 (Insulin-like Growth Factor)
WHOOP Advanced Labs · Labcorp OnDemand · Life Extension Elite · Everlywell · Mito Health · InsideTracker · Marek Health Base · Empirical Health · Oura Health Panels · SiPhox Health · Vitality Blueprint Standard · Ultrahuman Blood Vision Annual
11 providers not itemized in our matrix
We have not itemized these marker by marker (some sell tests one at a time), so this page cannot say whether they offer IGF-1 (Insulin-like Growth Factor). Check with them directly.
Life Extension Standard · Quest Health · Ultrahuman Blood Vision · Lifeforce · Hundred Health · Personalabs · Walk-In Lab · HealthLabs · WHOOP Specialized Panels · Marek Health Essential · Vitality Blueprint Upload
Frequently Asked Questions
What is the optimal range for IGF-1 (Insulin-like Growth Factor)?
Published position: Middle of the age-adjusted range (Cohort data show a J-curve: both low and high IGF-1 associate with higher mortality). Lab reference interval: Age-dependent, typical adult: 100-300 ng/mL. That is what a lab report flags against, not an optimal target.
Which blood test providers include IGF-1 (Insulin-like Growth Factor)?
9 of the 21 blood testing panels we itemize marker by marker include IGF-1 (Insulin-like Growth Factor) in their panels. This biomarker is widely available across major providers.
Medical Disclaimer
This information is for educational purposes only and is not medical advice. Always consult with a qualified healthcare provider about your specific health needs.
Last reviewed Sep 23, 2026 · First published Sep 30, 2025