Safety Profile
Known Safety Concerns
- CONTRAINDICATED in phenylketonuria (PKU) -- neurotoxic accumulation
- MAOI interaction -- hypertensive crisis risk
- Blood pressure elevation at high doses
- Warning label required for PKU in aspartame-containing products
Contraindications
- CONTRAINDICATED in phenylketonuria (PKU) -- neurotoxic accumulation
- MAOI interaction -- hypertensive crisis risk
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
L-phenylalanine is a tyrosine and dopamine precursor. It is absolutely contraindicated in phenylketonuria (PKU), where phenylalanine accumulates to neurotoxic levels. Aspartame contains phenylalanine and must carry a PKU warning. May interact with MAOIs causing hypertensive crisis. Blood pressure effects possible at high doses.
Biological and Chemical Classification
- Scientific Name
- L-Phenylalanine
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Executive Summary — Ingredient Assessment
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or RCT)
- Main clinical benefit observed: Metabolic
- Evidence consistency: High consistency across studies (100%)
- CONTRAINDICATED in phenylketonuria (PKU) -- neurotoxic accumulation
- MAOI interaction -- hypertensive crisis risk
- Blood pressure elevation at high doses
- Warning label required for PKU in aspartame-containing products
The available scientific evidence for L-Phenylalanine indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.
Total SETI Score
High risk| Evidence quality | 10/40 |
| Evidence consistency | 20/20 |
| Safety signals | 0/20 |
| Study recency | 10/10 |
| Evidence transparency | 10/10 |
Evidence Summary
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or systematic review)
- 0 studies identified benefits or no safety concern (GREEN)
- 10 studies reported limited or advisory safety evidence (YELLOW)
Evidence Policy
Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.
Last updated: 25 მარ 2026, 12:49
Evidence Distribution
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Observational / other LOW evidence YELLOWSoft-Sensing-Guided Glucose/l-Phenylalanine Cofeeding Strategy and Transcriptomic Analysis of the Optimal l-Phenylalanine Supply Range for Efficient u03b2-Phenylethanol Biosynthesis in Saccharomyces cerevisiae. ↗Yang C et al.. Soft-Sensing-Guided Glucose/l-Phenylalanine Cofeeding Strategy and Transcriptomic Analysis of the Optimal l-Phenylalanine Supply Range for Efficient u03b2-Phenylethanol Biosynthesis in Saccharomyces cerevisiae.. J Agric Food Chem. 2026. PMID:41848368.PMID 41848368 ↗Journal J Agric Food ChemYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41848368/
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Observational / other LOW evidence YELLOWAn integrated in vitro antioxidant/in vivo metabolomics approach unravels the synergistic effects between oregano essential oil and vitamin C as a nutritional… ↗Sayedahmed MM et al.. An integrated in vitro antioxidant/in vivo metabolomics approach unravels the synergistic effects between oregano essential oil and vitamin C as a nutritional strategy for alleviating heat stress in rabbits.. J Anim Sci. 2026. PMID:41837378.PMID 41837378 ↗Journal J Anim SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41837378/
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Observational / other LOW evidence YELLOWElectrochemical discrimination of phenylalanine enantiomers in blood using an ATO-u03b3-CD nanocomposite-modified SWCNT platform. ↗Comnea-Stancu IR et al.. Electrochemical discrimination of phenylalanine enantiomers in blood using an ATO-u03b3-CD nanocomposite-modified SWCNT platform.. Anal Chim Acta. 2026. PMID:41833410.PMID 41833410 ↗Journal Anal Chim ActaYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41833410/
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Observational / other LOW evidence YELLOWMetabolomics reveals early pregnancy serum metabolic changes and predictive biomarkers in gestational diabetes mellitus. ↗Wang F et al.. Metabolomics reveals early pregnancy serum metabolic changes and predictive biomarkers in gestational diabetes mellitus.. Nutr Metab (Lond). 2026. PMID:41832565.PMID 41832565 ↗Journal Nutr Metab (Lond)Year 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41832565/
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Observational / other LOW evidence YELLOWComparative Metabolomics and Lipidomics of Meat from Duroc u00d7 Guangdong Small-Eared Spotted Pigs and Commercial Duroc u00d7 (Landrace u00d7 Yorkshire) Pigs. ↗Liu W et al.. Comparative Metabolomics and Lipidomics of Meat from Duroc u00d7 Guangdong Small-Eared Spotted Pigs and Commercial Duroc u00d7 (Landrace u00d7 Yorkshire) Pigs.. Foods. 2026. PMID:41829103.PMID 41829103 ↗Journal FoodsYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41829103/
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Observational / other LOW evidence YELLOWIntegrated transcriptome and metabolome analysis reveals the molecular mechanism underlying differences in Psa resistance between Actinidia valvata and Actinidia chinensis. ↗Zhu R et al.. Integrated transcriptome and metabolome analysis reveals the molecular mechanism underlying differences in Psa resistance between Actinidia valvata and Actinidia chinensis.. Front Plant Sci. 2026. PMID:41815418.PMID 41815418 ↗Journal Front Plant SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41815418/
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Observational / other LOW evidence YELLOWCo-Fermentation of Saccharomyces cerevisiae and Lactobacillus plantarum Enhances Mulberry Anthocyanin Stability via Amino Acid-Mediated Co-Pigmentation Mechanisms. ↗Yin X et al.. Co-Fermentation of Saccharomyces cerevisiae and Lactobacillus plantarum Enhances Mulberry Anthocyanin Stability via Amino Acid-Mediated Co-Pigmentation Mechanisms.. J Food Sci. 2026. PMID:41804074.PMID 41804074 ↗Journal J Food SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41804074/
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Observational / other LOW evidence YELLOWDevelopment of a dendritic cell-targeted vaccine strategy using proximity-induced conjugation. ↗Wang Z et al.. Development of a dendritic cell-targeted vaccine strategy using proximity-induced conjugation.. Theranostics. 2026. PMID:41799186.PMID 41799186 ↗Journal TheranosticsYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41799186/
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Observational / other LOW evidence YELLOWAmenability of the Gatekeeper Enzyme HphA to Engineering in the Homologation Pathway of lu2011Phenylalanine and lu2011Tyrosine through Homology-Based Site-Directed Mutagenesis. ↗Lang Harman RM et al.. Amenability of the Gatekeeper Enzyme HphA to Engineering in the Homologation Pathway of lu2011Phenylalanine and lu2011Tyrosine through Homology-Based Site-Directed Mutagenesis.. ACS Omega. 2026. PMID:41799147.PMID 41799147 ↗Journal ACS OmegaYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41799147/
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Observational / other LOW evidence YELLOWN-Propionyl aromatic Amino acids restore taste balance in reduced-salt soy sauce. ↗Guo T et al.. N-Propionyl aromatic Amino acids restore taste balance in reduced-salt soy sauce.. Food Chem. 2026. PMID:41795526.PMID 41795526 ↗Journal Food ChemYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41795526/
Score Transparency
0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.
Method: Q = number of approved references ÷ 10 (capped at 1.0)
Limited — mostly case reports or animal studies
Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.
Mixed or neutral — roughly equal benefit and risk signals
Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.
One or more monitoring-level safety signals active
Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.
Final GIRI Score for L-Phenylalanine. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
Full methodology & data sources
The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.
- References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
- Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
- Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
- Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a moderate safety concern. Caution is advised, particularly at high doses or in sensitive populations.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Moderate classification for L-Phenylalanine
A score of 4.0 places this ingredient in the Moderate band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
0 approved references.
Limited — mostly case reports or animal studies (Level 4–5).
Neutral or mixed — benefit and risk signals roughly balanced.
No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.
No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).
How are the Low / Moderate / High / Critical thresholds defined?
The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:
| Level | Score | Meaning |
|---|---|---|
| LOW | 0.0 – 2.9 | Sparse or predominantly beneficial evidence. No active safety alerts. |
| MODERATE | 3.0 – 5.4 | Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups. |
| HIGH | 5.5 – 7.4 | Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended. |
| CRITICAL | 7.5 – 10 | Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision. |
Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.