PeptidePrices safety rating
6/10 · Not FDA-approved
P21 Peptide Prices
7 vendors · 5 with an issuer-verified COA · lowest 10mg from $72.00 · checked
Where to buy P21 Peptide: 7 vendors compared
| Vendor | Price | Actions |
|---|---|---|
| 3-test panelVerified COAKovera Labs · Tested Aug 13, 2026 | $72.0010mg packageChecked today | Buy P21 Peptide from Pure Peptides |
| 4-test panelVerified COAFreedom Diagnostics · Tested Feb 16, 2026 | $72.24 | Buy P21 Peptide from SomaChems |
| $75.34 | Buy P21 Peptide from Atlas Longevity | |
| 2-test panelVerified COAOptima Labs | $92.2710mg packageChecked Sep 20 | Buy P21 Peptide from Peptides Lab UK |
| 3-test panelVerified COAKovera Labs · Tested Jun 28, 2026 | $96.002 × 5mg packages · 10mg totalChecked today | Buy P21 Peptide from Real Peptides |
| $174.60 | Buy P21 Peptide from Nationwide Peptides | |
| 3-test panelVerified COABioViridian | $216.00 | Buy P21 Peptide from American Peptides |
Tracked every day
P21 Peptide listing prices, tracked daily
The five cheapest in-stock package prices for P21 Peptide on each collected day, and the vendors that most often held those places.
Five cheapest in-stock package prices per day
Listed package price before coupons, any vial size. This is not the coupon-adjusted lowest 10mg price used to rank the comparison.
- Cheapest$44.00
- 2nd cheapest$48.00
- 3rd cheapest$55.80
- 4th cheapest$72.00
- 5th cheapest$83.71
Vendors most often in the cheapest five
- American Peptides17 days$120.00last seen Oct 7, 20260.0%
- Real Peptides15 days$48.000.0%
- Nationwide Peptides6 days$97.00last seen Sep 24, 20260.0%
- Pure Peptides4 days$72.00+63.6%
- Atlas Longevity4 days$83.71+49.6%
Current market data
P21 Peptide Price Report
A current summary of public listings after the price comparison above. Shipping and tax are not included.
The lowest current 10mg cost for P21 Peptide is $72.00 from Pure Peptides. The median across vendors is $92.27.
- Lowest 10mg cost
- $72.00Pure Peptides
- Median 10mg cost
- $92.27One normalized offer per vendor
- Lowest package total
- $44.00Pure Peptides · package size may differ
- Public COA coverage
- 100%7 of 7 vendors
What the market shows
PeptidePrices found 9 in-stock listings from 7 vendors, checked through Oct 9, 2026. The lowest 10mg cost is 22% below the vendor median of $92.27; 3 vendors (43%) fall below that median. 7 of 7 vendors (100%) publish public COA evidence.
A public COA link shows that a vendor publishes testing data. It does not prove that every listed vial has a matching current report. Match the product, strength, batch, and lot before relying on a report.
How this report is calculated
The headline and median use each vendor's lowest whole-package checkout cost to obtain at least 10mg. Smaller packages are multiplied until the target is met, while larger packages retain their full checkout price. The lowest package total is shown only as secondary context because package sizes differ. Known public coupon discounts are applied. Shipping, tax, and unverified promotions are excluded.
Research context
What is P21 Peptide? Research, safety, and status
P21 Peptide at a glance
Mechanism
Tetrapeptide derived from ciliary neurotrophic factor (CNTF); activates gp130 signaling; promotes BDNF expression and neurogenesis; enhances synaptic plasticity; reduces Alzheimer's tau pathology.
Research areas
Cognitive enhancement; neurogenesis; Alzheimer's prevention/treatment; neuroprotection; BDNF upregulation; memory and learning.
Regulatory / research status
Research / preclinical only
Half-life
Not established in humans.
Storage
Lyophilized vial: store at -20°C long-term or 2-8°C short-term, protected from light.
Reported side effects
Very limited human data. Generally well-tolerated in animal studies.
BDNF mimetic; limited data but no proven harms; theoretical mechanism favorable Safety ratings summarize published clinical data, adverse-event reporting, and regulatory status. How PeptidePrices rates evidence. Research information only, not medical advice.
Study highlights
- p21/CDKN1A is the primary effector of p53-driven cell cycle arrest and a central mediator of cellular senescence; it can function as both a classical tumor suppressor (arresting damaged cells) and, paradoxically, as a proto-oncogenic survival factor in established tumors, with its role determined by cellular context, subcellular localization, and interaction partners.
- A 2021 Science study found that p21-activated cells produce a bioactive secretome (PASP, including CXCL14) that recruits macrophages for immunosurveillance of stressed and precancerous cells, a tumor-suppressive mechanism; persistent p21 expression triggers M1 macrophage polarization and cytotoxic T-cell recruitment, placing stressed cells under immune clearance.
- Peptides derived from the p21 PIP-box domain can be delivered into cells using cell-penetrating sequences (e.g., Tat48-60); these constructs induce selective apoptosis in glioma and ovarian cancer cells by disrupting nuclear PCNA function, establishing proof-of-concept for p21-derived therapeutic peptides in oncology.
- A 2024 Cell Death & Disease study demonstrated that PI3K-alpha/delta inhibitors act as senolytics by accelerating proteasomal degradation of p21 specifically in therapy-induced senescent tumor cells, selectively killing them while sparing healthy proliferating cells, highlighting p21 stability as a therapeutic target for eliminating senescent cells.
Selected references
- p21 produces a bioactive secretome that places stressed cells under immunosurveillance · Science, 2021
- The role of p21 in cellular senescence and aging-related diseases · Mol Cells, 2024
- p21WAF1 and tumourigenesis: 20 years after · Curr Opin Oncol, 2013
- A sychnological cell penetrating peptide mimic of p21(WAF1/CIP1) is pro-apoptogenic · Peptides, 2007
- Inhibition of ovarian cancer cell proliferation by a cell cycle inhibitory peptide fused to a thermally responsive polypeptide carrier · Int J Cancer, 2010
- Combined inhibition of class 1-PI3K-alpha and delta isoforms causes senolysis by inducing p21WAF1/CIP1 proteasomal degradation in senescent cells · Cell Death Dis, 2024
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