MikroScore
Science-backed ingredient evidence
Weak Evidence Safety: Likely safe Study dose: 500 mg/day

D,L-Phenylalanine

Also known as: DLPA, DL-Phenylalanine, D,L-Phenylalanine

Summary Weak Evidence

DLPA combines the neurotransmitter precursor L-phenylalanine with the D-form, which may prolong endogenous endorphins. Moderate evidence, older study base.

EU Health Claims: No approved claims

Phenylalanine is recognized as an essential amino acid. No specific health claims for DLPA in the EU.

AI Summary

Quick verdict

DLPA combines the neurotransmitter precursor L-phenylalanine with the D-form, which may prolong endogenous endorphins. Moderate evidence, older study base.

What the evidence supports

L-phenylalanine has indirect evidence via the tyrosine/dopamine pathway. D-phenylalanine as an enkephalinase inhibitor was studied for pain and depression in the 1980s, with few new studies since.

What is NOT supported

Clinical human trials are absent or very weak. Long-term safety in humans is largely unexplored.

EU/EFSA status

Not approved. Phenylalanine is recognized as an essential amino acid. No specific health claims for DLPA in the…

Safety

Likely safe

This AI summary is generated from the structured data on this page.

Mechanism of Action

DLPA is a 50/50 mixture of both isomers. L-Phenylalanine is hydroxylated to L-tyrosine, then further to dopamine → norepinephrine → epinephrine. D-Phenylalanine is proposed to inhibit enkephalinase — an enzyme that breaks down endogenous endorphins — thereby prolonging natural pain relief.

Evidence

Evidence predominantly dates from the 1970s-80s. Beckmann (1979) showed DLPA as non-inferior to imipramine for depression in a small double-blind trial. For pain relief via enkephalinase inhibition, there is mechanistic plausibility but no modern RCTs. Overall: historically interesting but replication is lacking.

Safety

Contraindicated in phenylketonuria (PKU). Do not combine with MAO inhibitors or levodopa. May cause headaches, nausea, or anxiety in sensitive individuals. Generally well-tolerated in studies.

Dosage

500–1000 mg per day on an empty stomach. Avoid evening doses (stimulating via dopamine pathway).

Key Studies

D-phenylalanine in depressed patients: an open study

Beckmann H et al. (1977) n=12

Open study (n=20): D-phenylalanine showed antidepressant effects in 12 of 20 patients. Methodologically weak (no placebo).

PubMed PMID 335027

DL-phenylalanine versus imipramine: a double-blind controlled study

Beckmann et al. (1979)

Double-blind study (n=40): DLPA was non-inferior to imipramine (150 mg) for depression. Small sample, replication needed.

PubMed PMID 387000

Analgesic properties of enkephalinase inhibitors: animal and human studies

Ehrenpreis et al. (1985)

Review: D-phenylalanine inhibits enkephalinase, prolonging endogenous endorphin activity. Animal studies and initial clinical data positive.

PubMed PMID 2934746
Editorial notice: For most ingredients described here, no health claims are approved in the EU (Regulation (EC) 1924/2006). Evidence levels are editorial assessments of research quality — not health promises. This content is not a substitute for medical advice and does not constitute a recommendation to treat, alleviate, or prevent any disease.