ALP (Alkaline Phosphatase)
ALP is an enzyme found mainly in liver bile ducts and bone. Elevated levels suggest bile duct obstruction, cholestasis, bone turnover from fracture or Paget disease, or normal growth in children and pregnancy. GGT helps distinguish a liver source (GGT also high) from a bone source (GGT normal). Low ALP can indicate zinc or magnesium deficiency or hypophosphatasia.
Units: U/L. Check the units on your report before comparing to any range here.
Optimal range: who says what
No institution or named practitioner we track states an optimal target for ALP (Alkaline Phosphatase). How we verify ranges.
- Lab reference interval44-147 U/LWhat a lab report flags against. A lab interval is not an optimal target.
20 of 21 itemized panels
Liver Function
What is ALP (Alkaline Phosphatase)?
ALP (Alkaline Phosphatase) is an enzyme found primarily in your liver and bones, with smaller amounts in intestines, kidneys, and placenta (during pregnancy). ALP plays a role in breaking down proteins and is particularly concentrated in the bile ducts of the liver and in bone-forming cells (osteoblasts).
The challenge with ALP is determining the source: liver or bone. Elevated ALP from liver typically indicates cholestasis (bile duct obstruction or impaired bile flow), while bone-source ALP indicates increased bone turnover from growth, fracture healing, or bone disease. GGT is the key differentiator—if both ALP and GGT are elevated, the source is likely liver; if only ALP is elevated, consider bone disorders.
ALP can be mildly elevated in healthy growing children and adolescents due to bone growth, and during pregnancy due to placental ALP. In adults, persistently elevated ALP warrants investigation. Low ALP, though less common, can indicate nutritional deficiencies (zinc, magnesium, vitamin B6) or rare genetic conditions like hypophosphatasia.
Why ALP Is Your Bile Duct and Bone Health Sentinel
- Detects cholestasis: Elevated ALP with GGT indicates bile duct obstruction, primary biliary cholangitis, or drug-induced cholestasis before jaundice appears
- Bone disease screening: Isolated ALP elevation (normal GGT) suggests Paget's disease, osteomalacia, bone metastases, or hyperparathyroidism
- Early cancer detection: Markedly elevated ALP can indicate bone or liver metastases from various cancers
- Medication monitoring: Many drugs cause cholestatic liver injury with ALP elevation (antibiotics, antifungals, hormones)
- Nutritional status: Low ALP may indicate zinc, magnesium, or vitamin B6 deficiency, often overlooked
Interpretation bands (curated, PMID-backed)
Holder: OptimizeBiomarkers editorial synthesis of: Elevated serum alkaline phosphatase and cardiovascular or all-cause mortality risk in dialysis patients: A meta-analysis (Fan et al., 2017); Can serum levels of alkaline phosphatase and phosphate predict cardiovascular diseases and total mortality in individuals with preserved renal function? A systemic review and meta-analysis (Li et al., 2014); Elevated Levels of Serum Alkaline Phosphatase are Associated with Increased Risk of Cardiovascular Disease: A Prospective Cohort Study (Liu et al., 2023). No single paper sets these cutoffs; for attributed targets see who says what.
Optimal (Adult)35-100 U/L▼
- Optimal range for adults indicating healthy bile flow and normal bone turnover
- Values in this range suggest good liver and bone health, adequate nutrition, and low inflammation
- Note: Children and adolescents normally have higher ALP due to bone growth (can be 2-3x adult values)
Borderline High100-150 U/L▼
- Upper normal range; may warrant investigation depending on age and context
- Check GGT to determine if liver-related
- Consider bone source if isolated
- Retest in 3-6 months and investigate if rising trend
- Rule out benign causes (post-meal elevation in blood type O/B secretors, recent bone healing)
Moderately Elevated150-300 U/L▼
- Requires investigation
- If GGT also elevated: Evaluate for cholestatic liver disease, bile duct obstruction, primary biliary cholangitis, drug-induced liver injury
- Order liver ultrasound or MRCP
- If GGT normal: Consider bone disorders (Paget's disease, healing fracture, osteomalacia, vitamin D deficiency)
- Order bone-specific ALP isoenzyme, calcium, phosphate, PTH, vitamin D
Severely Elevated>300 U/L▼
- Indicates significant pathology requiring urgent workup
- Liver causes (with elevated GGT): Bile duct obstruction, primary sclerosing cholangitis, liver metastases, severe cholestatic drug reaction
- Order urgent imaging (ultrasound/MRCP)
- Bone causes (normal GGT): Paget's disease, bone metastases, osteomalacia, hyperparathyroidism
- Order bone scan, PTH, calcium, vitamin D
- Levels >1000 U/L suggest severe disease
- Elevated serum alkaline phosphatase and cardiovascular or all-cause mortality risk in dialysis patients: A meta-analysis.
- Can serum levels of alkaline phosphatase and phosphate predict cardiovascular diseases and total mortality in individuals with preserved renal function? A systemic review and meta-analysis.
- Elevated Levels of Serum Alkaline Phosphatase are Associated with Increased Risk of Cardiovascular Disease: A Prospective Cohort Study.
What raises or lowers ALP
Causes of high ALP
- Liver/biliary causes (with elevated GGT): Cholestasis (bile duct obstruction from gallstones, tumors, strictures), Primary biliary cholangitis (autoimmune), Primary sclerosing cholangitis, Infiltrative diseases (sarcoidosis, amyloidosis), Drug-induced cholestasis (antibiotics, oral contraceptives, anabolic steroids), Liver metastases or tumors, Fatty liver disease (less common)
- Bone causes (normal GGT): Paget's disease of bone, Osteomalacia (vitamin D deficiency), Hyperparathyroidism (check calcium and PTH), Bone metastases (cancer spread to bone), Healing fractures, Osteosarcoma (rare), Hyperthyroidism (increased bone turnover)
- Physiologic: Pregnancy (placental ALP), childhood/adolescent growth, Post-meal in blood type O/B secretors
- Other: Chronic kidney disease, Congestive heart failure, Certain cancers (lung, kidney), Lymphoma
Causes of low ALP
- Zinc deficiency: Most common nutritional cause of low ALP
- Magnesium deficiency: Required for ALP enzymatic function
- Vitamin B6 deficiency: ALP requires pyridoxal phosphate as cofactor
- Hypophosphatasia: Rare genetic disorder causing low ALP and bone disease
- Severe anemia or malnutrition
- Hypothyroidism (mild decrease)
- Pernicious anemia (vitamin B12 deficiency)
- Wilson's disease (copper accumulation)
- Medications: Corticosteroids, chemotherapy, excessive vitamin D intake
Symptoms when ALP is high or low
When high
Symptoms depend on underlying cause:
- Liver/bile duct: Jaundice (yellowing of skin/eyes), dark urine, pale stools, itching (pruritus), right upper quadrant pain, nausea
- Bone disease: Bone pain (especially in Paget's disease), deformity, hearing loss (Paget's), fractures, muscle weakness
- Often asymptomatic: Mild ALP elevations (100-150 U/L) frequently cause no symptoms and are found incidentally
Severe ALP elevation (>300 U/L) typically causes more pronounced symptoms. Persistent itching with elevated ALP suggests cholestasis and warrants urgent evaluation. Bone pain with very high ALP (>500 U/L) may indicate Paget's disease or metastatic bone disease.
When low
Low ALP (<30 U/L) is less common but can indicate:
- Fatigue and weakness
- Bone pain or increased fracture risk (if hypophosphatasia)
- Poor wound healing
- Anemia (if nutritional deficiency)
- Neurological symptoms (if severe zinc or B6 deficiency)
Low ALP often indicates nutritional deficiencies (zinc, magnesium, B6) or rare genetic conditions like hypophosphatasia. Address deficiencies first; if ALP remains low despite repletion, consider genetic testing.
How to move ALP
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.
Treat Liver-Related Causes (if ALP + GGT elevated)
- Identify and remove offending medications: Common culprits include antibiotics (amoxicillin-clavulanate, fluoroquinolones), antifungals, anabolic steroids, birth control pills, NSAIDs
- Ursodeoxycholic acid (UDCA): 13-15 mg/kg daily for primary biliary cholangitis or other cholestatic conditions (prescription)
- Treat underlying conditions: Address biliary obstruction (may require ERCP or surgery), manage inflammatory bowel disease if primary sclerosing cholangitis
- Support bile flow: Artichoke extract, milk thistle, and phosphatidylcholine may support bile health
- Weight loss if obese: Non-alcoholic fatty liver disease can cause cholestatic pattern with ALP elevation
Optimize Bone Health (if isolated ALP elevation)
- Vitamin D: Correct a deficiency (the vitamin D page lists who targets which level). Supplement 2000-5000 IU daily if deficient. Vitamin D deficiency causes osteomalacia with high ALP
- Calcium and phosphate: Ensure adequate intake (1000-1200 mg calcium daily, 700 mg phosphate). Check serum levels
- Magnesium: 400-500 mg daily (glycinate or threonate forms). Essential for bone health and ALP regulation
- Vitamin K2 (MK-7): 90-180 mcg daily directs calcium to bones rather than soft tissues
- Treat Paget's disease: Bisphosphonates (alendronate, risedronate) if Paget's confirmed. Normalizes ALP in most patients
Address Low ALP (if <30-35 U/L)
- Zinc supplementation: 15-30 mg daily (zinc picolinate or glycinate). Zinc deficiency is most common cause of low ALP
- Magnesium: 400-500 mg daily. Required for ALP enzyme function
- Vitamin B6: 25-50 mg daily if deficient. ALP requires pyridoxal phosphate (B6) as cofactor
- Copper: Ensure adequate intake (1-2 mg daily) but avoid excess. Both deficiency and excess can affect ALP
- Protein intake: Ensure 0.8-1.2 g/kg body weight daily. Severe protein malnutrition lowers ALP
Support Liver and Bile Flow
- Fiber and bile acid binding: Adequate fiber intake (25-35g daily) supports healthy bile acid metabolism
- Omega-3 fatty acids: 2-4g EPA+DHA daily reduces liver inflammation
- Taurine: 500-1000 mg daily. Amino acid that conjugates bile acids and supports liver function
- Avoid alcohol: Even moderate drinking can impair bile flow and elevate ALP
- Bitter foods: Arugula, dandelion greens, artichoke stimulate bile production and flow
Lifestyle and Monitoring
- Regular weight-bearing exercise: Builds bone density and normalizes bone turnover markers including ALP
- Sunlight exposure: 15-30 minutes daily (arms/legs) for vitamin D production
- Avoid smoking: Increases bone turnover and ALP, accelerates bone loss
- Monitor trend over time: ALP should be stable in healthy adults. Rising trend requires investigation even if still "normal"
- Timing: Blood type O and B secretors can have transient ALP elevation after fatty meals. Test fasting for accuracy
When to retest
- After addressing deficiencies: If low ALP, retest after 2-3 months of zinc/magnesium/B6 supplementation to confirm normalization
- After medication changes: If starting or stopping suspected medication, retest in 4-8 weeks
- If borderline elevated (100-150 U/L): Retest in 3-6 months with GGT, ALT, and bilirubin to assess trend and determine liver vs bone source
- If moderately elevated (150-300 U/L): Retest in 4-12 weeks with comprehensive panel (GGT, ALT, AST, bilirubin, calcium, phosphate, vitamin D). Order imaging if liver source suspected
- If severely elevated (>300 U/L): Urgent workup including ALP isoenzyme analysis, imaging (ultrasound, bone scan), and specialist referral. Monitor every 2-4 weeks until diagnosis and treatment established
- During treatment: Monitor every 3-6 months to assess response to therapy (UDCA for PBC, bisphosphonates for Paget's)
Scientific Evidence
ALP and Cardiovascular Disease
In 26,389 adults followed for 7.3 years, the highest ALP quartile had more incident cardiovascular disease than the lowest (HR 1.22 in men, 1.12 in women). The association held within the normal range of 40-150 U/L.
ALP in Primary Biliary Cholangitis
In 4,845 patients with primary biliary cholangitis from 15 cohorts, ALP and bilirubin predicted liver transplantation or death. One year after enrollment, 84% of patients with ALP at or below 2 times the upper limit of normal survived 10 years, versus 62% of those above it.
Which Providers Test ALP (Alkaline Phosphatase)?
Cheapest: Oura Health Panels at $99/year. Most comprehensive: Function Health, 160+ biomarkers for $365/year.
20 panels that include it, cheapest first
| Provider | Annual Cost | Total Biomarkers | $/Biomarker |
|---|---|---|---|
| $99 | 50 | $1.98 | |
| $190 | 100+ | $1.90 | |
| $250 | 65 | $3.85 | |
| $297 | 100+ | $2.97 | |
 Labcorp OnDemand | $338 | 50+ | $6.76 |
 Superpower | $349 | 100+ | $3.49 |
| $349 | 75+ | $4.65 | |
 WHOOP Advanced Labs | $349 | 65 | $5.37 |
 Function Health | $365 | 160+ | $2.28 |
| $365 | 100+ | $3.65 | |
| $375 | 108 | $3.47 | |
| $449 | 83 | $5.41 | |
| $495 | 80+ | $6.19 | |
| $499 | 100+ | $4.99 | |
| $700 | 138 | $5.07 | |
| $895 | 100+ | $8.95 | |
| $996 | 59 | $16.88 | |
| $1188 | 70+ | $16.97 | |
| $1198 | 40+ | $29.95 | |
| $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.
1 itemized panel does not include ALP (Alkaline Phosphatase)
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 ALP (Alkaline Phosphatase). Check with them directly.
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Experts discussing ALP (Alkaline Phosphatase)
Podcast episodes where clinicians and researchers cover this marker in depth. Curated by hand; an episode is listed only when the marker is a substantial topic, not a passing mention.
Frequently Asked Questions
What is the optimal range for ALP (Alkaline Phosphatase)?
No institution or named practitioner we track states an optimal target for ALP (Alkaline Phosphatase). Lab reference interval: 44-147 U/L. That is what a lab report flags against, not an optimal target.
Which blood test providers include ALP (Alkaline Phosphatase)?
20 of the 21 blood testing panels we itemize marker by marker include ALP (Alkaline Phosphatase) in their panels. This biomarker is widely available across major providers.
Related: YouBoost rates lifestyle and supplement interventions by evidence.
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