Browser extension
Price Comparison
Vendor prices per mg or per unit, by product form, with shipping to your country.
Price Comparison brings the Peptide Library Shop to your toolbar. Search a compound, pick a product form, and compare every vendor offer on price, price per mg (or per capsule or bottle), size, rating and whether the vendor ships to your country.
Offers are compared only within one form: a nasal spray, a vial and a bottle of capsules of the same compound are different products, and a price per mg does not make them equal.
Coming soon to Chrome, Edge, Firefox, Opera and Safari
Account: No.
What it does
Price per mg or per unit
After the vendor’s own coupon where it states one, so offers of different sizes line up.
Forms kept apart
Vials, solutions, pens, nasal and oral sprays, capsules and tablets each get their own comparison.
Shipping to you
Pick your country once; offers from vendors that ship there come first, and the vendor’s stated shipping cost shows when it states one.
Freshness
Every offer shows when its price was last checked. Prices not seen for a week say so.
Ratings
Vendor ratings and review counts from the Peptide Library vendor directory, where they exist.
How it works
Prices come from vendors’ own sites, collected daily by Peptide Library. No currency is converted and no price is estimated.
Ranking puts shipping eligibility first, then value and rating. Whether a link earns a commission never changes the order.
A vendor page opens only when you click “Visit vendor”. The extension never changes links on other websites.
Privacy
- • Your shipping country stays on your device and is sent only to check which vendors ship there.
- • No access to the sites you browse. Clicks and offer views are counted (without any id) only if you agree to share usage counts.
Full details: privacy policy · support
Browser support
| Browser | Needs | Get it |
|---|---|---|
| Google Chrome | Chrome 116 or later | Coming soon |
| Microsoft Edge | Edge 116 or later | Coming soon |
| Mozilla Firefox | Firefox 140 or later | Coming soon |
| Opera | Opera 102 or later | Coming soon |
| Safari | Safari 17 or later | Coming soon |
On peptidelibrary.app
- Peptide Shop · The full Shop with vendor profiles and coupons.
- Peptide price index · Typical prices per mg across vendors.
- How rankings work · Why offers are ordered the way they are.
Frequently asked questions
Are these affiliate links?
Some are. Peptide Library may earn a commission when you buy through a “Visit vendor” link, at no extra cost to you. Each affiliate link is labeled, and commissions never change the ranking.
Does the extension change links on other websites?
No. It has no access to the pages you visit. A vendor page opens only when you click “Visit vendor” in the extension.
How current are the prices?
Vendor catalogs are checked daily. Each offer shows when its price was last seen; offers not seen for 30 days are removed.
Why can’t I compare a spray with a vial?
They are different products with different amounts per use. The extension compares offers only within one product form.
Does Peptide Library sell peptides?
No. It lists offers vendors publish so researchers can compare them. It does not sell anything or recommend a product or amount.
More Peptide Library extensions
Research and educational use only. Not medical advice. Peptide Library does not sell peptides.