Evidence-led, not sales-led
Most of what you read about peptides is written by someone selling them.
We explain what these ingredients do, what they don't, and how strong the evidence actually is — in plain English, with the sources attached. We don't take money from anyone we write about.
Or pick a starting point below — no account, no email required to read anything.
Learn
Learn about a peptide or ingredient
What it does, what the research shows, and how strong that evidence is (graded A to D), with sources. This is about the ingredient, not any one product.
Check
Check a specific product
See which products we checked against our published standard, what each one passed, and when we last source-checked it. One product named, review incomplete; most of the market, checked against the same bar, does not.
Two different questions. An evidence grade says how strong the research is for an ingredient. It is not a safety or quality verdict on any product. A copper peptide serum, a prescription injection and a "research use only" vial each sit in a different legal category (see Are peptides legal?). Looking for a quick answer? Do copper peptides actually work?
We grade the evidence
The Library rates each ingredient's human-trial evidence A (strong) to D (animal/lab only) — the science, independent of any product.
We check the product
The Register checks whether a specific, real product actually meets a published, verifiable standard — labelling, testing, and marketing claims.
Start here
All ingredients →New to peptides
Peptide skincare for beginners
Start with one peptide, at a stated percentage, for twelve weeks. Almost every mistake is starting with too many products at once.
Most asked
Do copper peptides actually work?
Short answer: yes for firmness and fine lines. No for hair, acne, or anything injected.
Buying guide
What percentage of peptide should a serum contain?
3% for Matrixyl, 10% for Argireline in the trial that produced its headline result. Most brands won't tell you either.
Recently updated
Legal status tracker →11 September 2026
Copper peptides vs retinol
You don't have to choose. We also say plainly where the published advice contradicts itself.
11 September 2026
How to use copper peptides
One real incompatibility, and it isn't the one most articles warn you about.
8 September 2026
FDA status: what changed in 2026
Twelve peptides left Category 2 in April. That is not the same as becoming legal, and the difference matters.
New to the whole topic
All ingredients →Start here
What is a peptide?
A short chain of amino acids — the same building blocks as proteins, just fewer of them. The plain answer, without the jargon.
The closest thing to a verdict
Are peptides worth it?
Yes, for two or three specific things. No, for most of what's loudly marketed under the same word. Which is which, by name.
Ingestible
Do collagen peptides actually work?
Genuinely better evidence than most supplements — with the honest caveat about who funded the trials.
Matrixyl and Argireline
All ingredients →Grade A evidence
Matrixyl 3000
Around 20% reduction in wrinkle depth at 3% — but most of the testing behind that figure is the manufacturer's own.
Grade B evidence
Argireline
Marketed as "Botox in a bottle." At the tested 10% it has a real effect. Most products use far less.
Comparison
Matrixyl vs Argireline
Different jobs, not competing products — one for collagen loss, one for expression lines.
One email a week
A new ingredient page, what moved in the regulatory picture, and what we found when we checked a brand's paperwork. No launch hype, no affiliate blasts, unsubscribe in one click.