Cyclic Glycine-Proline (cGP)
IGF-1 Bioavailability Regulator & Neuroprotective Peptide
Community Research
Join others researching Cyclic Glycine-Proline — share findings, ask questions, and learn from real experiences
Endogenous cyclic dipeptide found in plasma, breast milk, and cerebrospinal fluid. Functions as metabolite of IGF-1, regulating its bioavailability through competitive binding to IGFBP-3. Demonstrates neuroprotective, cognitive-enhancing, and cardioprotective properties supported by clinical trials.
Competes with IGF-1 for IGFBP-3 binding, normalizing bioavailable IGF-1 levels. Acts as positive allosteric modulator of AMPA and GABA-A receptors. Increases BDNF levels via Akt/MDM2-p53 pathway activation.
Molecular Data
??cyclo(Gly
Position 1
Pro)
Position 2
Research Indications
Higher cGP levels correlate with improved memory retention in elderly populations
Protects neural stem cells from oxidative stress; efficacy demonstrated in stroke models
Mouse studies show reduced amyloid plaque load and improved spatial memory
Clinical study showed increased CSF cGP and reduced anxiety/depression scores
Clinical trial improved vascular complications and normalized HbA1c%
Demonstrated systolic blood pressure reduction in clinical observations
Higher cGP/IGF-1 ratios associated with favorable clinical outcomes
Maintained ratios correlate with preserved cognitive function with age
Dosing Protocols
Preferred route with excellent bioavailability and blood-brain barrier crossing.
| Goal | Dose | Frequency | Route |
|---|---|---|---|
| General cognitive support | 20-40 μg | 1x daily | Oral capsule |
| Neuroprotection/anti-aging | 40-50 μg | 1x daily | Oral capsule |
| Metabolic/cardiovascular support | 40-100 μg | 1x daily | Oral capsule |
| Via blackcurrant extract | 300 mg BCA | 2x daily | Oral capsule |
Interactions
What to Expect
Side Effects & Safety
Stop Signs - Discontinue if:
- Allergic reactions (rash, difficulty breathing, swelling)
- Unexpected blood glucose changes
- Unusual fatigue or weakness
Contraindications
- Consult healthcare provider if taking IGF-1 or growth hormone medications
- Limited long-term human data available
- Not studied in pregnancy
Quality Checklist
Good Signs
- Third-party tested for purity and potency
- Clear cGP content labeling (typically in micrograms per serving)
- Natural blackcurrant-derived sources from New Zealand
- Sealed containers protected from moisture and light
Warning Signs
- Products lacking clear cGP content specification
Bad Signs
- Extreme therapeutic claims unsupported by research
- Vague concentration descriptions
Frequently Asked Questions
Can cyclic glycine-proline improve cognitive function in healthy people, not just disease states?
Yes, research shows higher cGP levels correlate with improved memory retention in healthy elderly populations. Clinical trials demonstrated enhanced cognitive function in normal aging, suggesting benefits for preserving mental sharpness beyond treating disease—relevant for anti-aging protocols.
What's the advantage of blackcurrant extract over pure cGP supplements?
Blackcurrant extract provides cGP at approximately 300mg per serving in a natural, whole-food matrix that may improve bioavailability and provide additional antioxidants. Pure cGP comes in microgram quantities (20-100mcg), so extract forms offer higher doses though containing other compounds alongside cGP.
Does cGP actually help with Parkinson's disease or just animal models?
One human clinical study showed blackcurrant supplementation (which raises CSF cGP by 74%) reduced anxiety and depression scores in Parkinson's patients. While animal models show more dramatic neuroprotection, the human evidence supports cognitive and mood benefits, though larger trials are needed.
Can cyclic glycine-proline be used long-term without breaks?
Most protocols recommend 4-12 week cycles, though human safety data for long-term continuous use is limited. As cGP is an endogenous metabolite naturally found in cerebrospinal fluid and breast milk, extended use appears relatively safe, but cycling allows assessment of individual response and prevents potential tolerance.
References
Related Peptides
Disclaimer
This information is for educational and research purposes only. Consult a healthcare professional before use.