Cross-referencing clinical data
A pairing appears on this page only when a trial gave both ingredients together and measured the result. N-phenylacetyl-L-Prolylglycine ethyl ester has none that clears that bar.
Stitching two separate single-ingredient studies into a pairing is the one thing this engine will not do. When a study of the combination itself holds up at source, it lands here with its citation.
No invented synergy. Where actives were studied on their own rather than together, the record shows each on its own evidence, never a combined effect no trial measured.
Research strength. Research strength says how much work stands behind the combination. It is never a product score.
Independent record. Every finding is cited to a named trial, dated, and never written by the brand.
20 pairings are live across the library today. Checked 20 July 2026.
No study gave these as a pair, so they are not in the card above. But the reason they belong together is settled biochemistry, not a guess, so it is worth knowing.
Alpha-GPC is paired with racetam-family compounds on the reasoning that cholinergic supply should keep up with any cholinergic demand the other compound creates. That reasoning comes from user practice and from the older piracetam literature rather than from any study of this dipeptide. No trial has tested the combination. It is convention, and it should be labelled as convention.
Citicoline is the other standard cholinergic partner in this category, chosen for the same reason as alpha-GPC and differing mainly in that it also supplies cytidine. Products combine it with racetam-family compounds as a matter of habit. There is no combination data involving this specific dipeptide. Read it as formulation practice.
Theanine is added to nootropic stacks to take the edge off subjective overstimulation, a use inherited from the caffeine and theanine pairing. Whether that transfers to this compound has not been tested. Anyone reporting irritability from a stack is describing an outcome that has not been characterised in a trial. This row exists because the pairing is common, not because it is supported.
Caffeine appears in the same stacks by default rather than through any shared pathway with this dipeptide. Stacking two agents that each affect subjective alertness makes any adverse response harder to attribute to one of them. That attribution problem is the practical reason to name the pairing. It is co-use, not synergy.
The molecule is a phenylacetyl-prolyl-glycine ethyl ester, so glycine is one of the amino acids released when esterases and peptidases break it down. That makes glycine a metabolite rather than a partner. Naming it clarifies the structure for anyone reading the chemical name. It is not a reason to combine the two.
Proline is the second residue in the dipeptide backbone and appears in the cyclic prolylglycine fragment produced on hydrolysis. As with glycine, this is chemistry of the molecule rather than a stacking recommendation. Both amino acids are abundant in ordinary protein intake. The relationship is descriptive.
Nothing specific on file for N-phenylacetyl-L-Prolylglycine ethyl ester. Match the label to the daily amount above, and tell your doctor what you take.
Not medical advice. Show the label to your pharmacist.FDA Disclaimer: These statements have not been evaluated by the Food and Drug Administration. This information is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult your healthcare provider before starting any supplement regimen.