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Glycomacropeptide (Casein Glycomacropeptide)
A 64-amino-acid peptide released from kappa-casein during cheese-making, sold both as a whey-derived satiety supplement and (amino-acid-fortified) as a low-phenylalanine protein for PKU. Honest appraisal: the appetite/satiety evidence is genuinely mixed — several acute RCTs found NO effect of GMP itself on CCK, satiety ratings, or food intake, while a few found small reductions in energy intake. Its established, evidence-supported use is as a near-phenylalanine-free protein substitute in phenylketonuria, where it works as well as (not clearly better than) amino-acid formulas.
What the evidence says
Most Glycomacropeptide studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2001–2026 with a typical study size of 25 participants.
Based on 38 studies · 1 meta-analysis · 23 RCTs · 154 total participants
Confidence
Moderate confidenceBy outcome
Appetite/satiety RCTs are mostly null, the single meta-analysis covers only niche PKU dietary use, and the promising glucose and gut effects come from one small RCT and preclinical data — keeping evidence emerging.
25 rigorous studies
24 randomized trials · 1 meta-analyses · 0 systematic reviews
Our evidence rating for Glycomacropeptide is accountable to this entire body of rigorous research indexed in PubMed — not a hand-picked subset.
PubMed · as of Jul 2026
1 trial ongoing or recruiting · 18 completed on ClinicalTrials.gov
1 of the completed trials have posted results
Registered trials show research momentum for Glycomacropeptide, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Sep 2026
Under EU law (Reg. 1924/2006), EFSA reviews whether a specific health claim for Glycomacropeptide meets the evidence standard. These are independent regulatory decisions on claims — not studies, and never counted toward the evidence score above.
Not authorised by EFSA
“Glycomacropeptide Recognized for hunger feeling reduction”
“Not authorised” means the specific claim wording did not meet the EU’s evidence standard — often a matter of dossier or phrasing, not proof of no effect. EFSA judges marketing claims and is kept separate from our study-based evidence score.
Source: EU Register of nutrition and health claims (European Commission / EFSA) · register snapshot Feb 2013
Glycomacropeptide (GMP), also called caseinomacropeptide (CMP) or casein macropeptide, is the hydrophilic C-terminal glycopeptide of kappa-casein, cleaved off and released into whey when chymosin clots milk during cheese-making.
In its native form it contains essentially no aromatic amino acids (phenylalanine, tyrosine, tryptophan), which is the basis for its two distinct uses.
As a satiety/weight supplement, GMP was promoted on the hypothesis that it stimulates cholecystokinin (CCK) release and underlies whey protein's reputed appetite-suppressing effect.
The honest evidence here is mixed and often null: in a 50-person crossover RCT (Lam 2009) there was no consistent satiety effect of GMP; an acute preload RCT in overweight men (Keogh 2010) found no difference in CCK, satiety ratings, or subsequent food intake; a normal-weight-women RCT (Chungchunlam 2014) found whey was more satiating than carbohydrate but GMP alone was not; and Burton-Freeman (2008) concluded GMP is 'not critical' to whey-induced satiety, with only sex-specific CCK patterns.
On the other side, Veldhorst (2009) found that whey *with* GMP lowered energy intake at the next meal versus whey without GMP, and a 2023 dose-finding crossover RCT in obese postmenopausal women (Hansen) reported higher postprandial amylin, improved glucose homeostasis, and shifts in the fecal microbiome with GMP supplementation.
Read together, GMP's satiety/appetite signal is weak and inconsistent — not a reliable weight-loss agent. GMP's better-established role is in phenylketonuria (PKU): when fortified with the limiting amino acids it lacks (CGMP-AA), it serves as an intact-protein alternative to amino-acid formulas.
A 2018 systematic review and meta-analysis (Pena) of eight short, small studies found no difference between GMP-AA and amino acids for blood phenylalanine control or other outcomes, while patients often prefer its palatability; three-year prospective PKU studies likewise found no clear advantage in body composition or growth, only non-significant trends.
Beyond humans, animal/in-vitro work suggests anti-inflammatory and gut-protective effects (e.g. down-regulating a type-2 immune response in a rat food-allergy model), but this has not been confirmed in clinical trials.
Overall the evidence is emerging/low for appetite and gut benefits, and established-but-niche for PKU dietary management.
GMP was hypothesized to stimulate cholecystokinin (CCK) release and other gut satiety hormones. Controlled trials have largely NOT confirmed a reliable CCK or satiety effect from GMP itself.
In one dose-finding RCT, GMP raised postprandial amylin and improved the insulin–glucagon ratio versus a soy meal, hinting at a glucose-homeostasis role that needs replication.
Native GMP contains essentially no aromatic amino acids, making it (once fortified with limiting amino acids) a low-phenylalanine protein source for PKU diets.
Animal and in-vitro studies report down-regulation of type-2 immune responses and oxidative/inflammatory stress, plus shifts in fecal microbiota — not yet validated in clinical digestive endpoints.
How Glycomacropeptide works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Relevant and potentially helpful — but only as an amino-acid-fortified medical food under metabolic-dietitian supervision; native GMP still contains residual phenylalanine and lacks some essential amino acids.
Avoid — GMP is derived from casein and may carry trace dairy proteins.
A food-derived milk peptide consumed in cheese/whey; likely safe in normal dietary amounts. No data for high supplemental doses — keep to food-level intake.
Tip: Take with food; reduce serving size
Tip: GMP forms are generally preferred over amino-acid formulas; try a different flavour/format
Glycomacropeptide has an evidence score of 3/10 — emerging evidence based on 31 indexed studies, including 1 meta-analysis. A 64-amino-acid peptide released from kappa-casein during cheese-making, sold both as a whey-derived satiety supplement and (amino-acid-fortified) as a low-phenylalanine protein for PKU. Honest appraisal: the appetite/satiety evidence is genuinely mixed — several acute RCTs found NO effect of GMP itself on CCK, satiety ratings, or food intake, while a few found small reductions in energy intake. Its established, evidence-supported use is as a near-phenylalanine-free protein substitute in phenylketonuria, where it works as well as (not clearly better than) amino-acid formulas. Representative study: PMID 30453665.
The commonly studied dose of Glycomacropeptide is Satiety/metabolic trials used ~15-30 g/day (e.g. 15 g GMP + 10 g whey, twice or thrice daily); acute preloads used 25-50 g. In PKU, GMP-AA replaces most daily protein per dietitian prescription. No validated dose for appetite or weight loss.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Glycomacropeptide is with meals. Take it with food. Satiety trials dosed GMP as a preload before a test meal or split across meals; in PKU it is taken with meals as a protein substitute.
Glycomacropeptide is generally well-tolerated and considered safe for most healthy adults at recommended doses. Reported side effects are uncommon and include mild GI symptoms (bloating, fullness), taste/palatability complaints (medical-food forms). Use caution if any of these apply to you: Milk allergy (GMP is a dairy/casein-derived peptide); Galactosemia (contains glycosylated sugar residues including galactose).
Bonito Peptides
Mostly mechanism / observationalShort ACE-inhibitory peptides from enzyme-digested dried bonito (Katsuobushi) fish muscle — notably the dipeptide Val-Tyr ("VY") and the prodrug-type pentapeptide LKPNM — sold as a food-derived supplement for blood pressure. Honest appraisal: a handful of small, mostly Japanese, often industry-linked RCTs show a modest blood-pressure drop in people with mild/high-normal hypertension, on the same ACE-inhibition mechanism as related fish/sardine and milk (lactotripeptide) peptides. The effect is small, the trials are small, and benefit concentrates in (pre)hypertensive people — not normotensives.
Lactotripeptides
Mostly mechanism / observationalTwo milk-casein-derived tripeptides — Val-Pro-Pro (VPP) and Ile-Pro-Pro (IPP) — produced by fermenting milk with Lactobacillus helveticus or hydrolysing casein. They inhibit ACE in vitro and have been studied extensively for blood pressure. Honest appraisal: multiple meta-analyses find a small, statistically-significant drop in systolic/diastolic BP, but the effect is modest, heterogeneous, larger in Japanese than Western trials, and dented by clear publication bias plus outright-null trials (e.g. the Dutch Engberink RCT).
Casein Hydrolysate
Mostly mechanism / observationalA milk-derived bioactive peptide — a tryptic hydrolysate of bovine αs1-casein standardized to the decapeptide α-casozepine (Lactium) — marketed for stress, anxiety, and sleep. Honest appraisal: the mechanism is real and food-derived (α-casozepine binds the benzodiazepine site of the GABA-A receptor in vitro), and a handful of small human RCTs show modest reductions in stress symptoms and cortisol plus some sleep-diary improvements. But several trials are industry-linked, two well-designed sleep RCTs were null on their primary endpoint, and effects are small. Well-tolerated; this is an ordinary dietary supplement, not a drug.
Soy Peptides
Mostly mechanism / observationalShort, bioactive fragments enzymatically cleaved from soy protein — soy protein hydrolysates plus named peptides like lunasin and soy ACE-inhibitory peptides. Unlike whole soy protein (a complete protein with an FDA cholesterol claim) or soy isoflavones (phytoestrogens), these are specific peptide fragments studied for cholesterol, blood pressure and antioxidant effects. Honest appraisal: the evidence is mostly in-vitro and animal. The one published human RCT (lunasin) was null. Emerging, not established.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 38 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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