Review · United States
P21 peptide
Reviewed on
Approval and product status
Animal and cell studies only. No FDA-approved U.S. P21 product was found.
FDA lists P-21, P021, and P21 under one chemical record. This record does not prove that a sold product contains the same compound used in a study. A name alone does not prove what is in a product or whether it was made safely.
What was measured in people?
- Health results · Unclear
- No P021 study in people was found in the searches completed on August 30, 2026.
- Body changes · Unclear
- Studies measured effects in mice, rats, or cells. They do not show what happens in people.
A change in a hormone or body signal does not by itself prove a health benefit.
Important limits
This tool is not an independent medical review. It does not recommend treatment.
No reviewed study sets a safe amount or way to take P21. Long-term safety in people is also unknown. This guide gives no directions for use, buying advice, or treatment advice.
Still unknown: No P021 study in people was found. The reviewed evidence does not show whether it improves memory, prevents dementia, or treats Alzheimer’s disease in people. It also does not establish a safe amount, long-term effects, or the quality of products sold with this name. Tests in human-derived cells happen in a lab. They are not studies in people.
This record cannot check a package, seller, batch, or personal treatment. It does not provide sport clearance.
Approval fact checks
“A P21 substance record means P21 is FDA-approved.”
Misleading. FDA says a Unique Ingredient Identifier, or UNII, helps identify a substance. It does not mean that FDA reviewed or approved a drug. No FDA-approved P21 product was found under the reviewed names.
Applies to: United States drug-approval status as checked for P21, P021, and P-21 on August 30, 2026.
Products in this review
These are selected records, not every product or form.
No product label record is included here. That is not a separate approval decision. Read the status and sources above.
What the research shows
A 2010 mouse study reported changes in learning, memory, and the growth of new brain cells. Later mouse studies reported changes in memory, nerve-cell connections, tau, or amyloid. Tau and amyloid are proteins studied in Alzheimer’s disease. An aged-rat study measured lower tau after P021 treatment. A cell study and another mouse study had mixed results. None of these studies tested P21 in people.
Read all P21 peptide fact checksSources used in this review
A source may support some statements, not all of them. Use the links above or this review to see what each source supports.
Show 9 sources
- FDA substance record for P-21, P021, and P21
U.S. Food and Drug Administration · Reference · 2026
Source accessed
- P21 learning, memory, and nerve-cell study in normal mice
PubMed · FEBS Letters · Preclinical · 2010
Source accessed
- Chronic P021 study in an Alzheimer-like mouse model
PubMed · Neurobiology of Disease · Preclinical · 2014
Source accessed
- Early P021 study in an Alzheimer-like mouse model
PubMed · Alzheimer’s Research & Therapy · Preclinical · 2017
Source accessed
- P021 tau study in aged rats
PubMed · Journal of Alzheimer’s Disease · Preclinical · 2015
Source accessed
- P021 study in lab-grown human nerve cells and a mouse model
PubMed · Journal of Neurodevelopmental Disorders · Preclinical · 2024
Source accessed
- ClinicalTrials.gov intervention search for P021
ClinicalTrials.gov · Trial registry · 2026
Source accessed
- NCBI Gene record for human CDKN1A, also called p21
National Center for Biotechnology Information · Reference · 2026
Source accessed
- Drugs@FDA approved-drug search
U.S. Food and Drug Administration · Regulatory · 2026
Source accessed