How to Compare Peptide Prices Per Milligram

By Editorial team. Updated Oct 15, 2026. Awaiting editor sign-off

Sticker prices for research peptides are hard to compare. One shop sells 5 mg vials and another sells 10 mg. One sells kits of ten vials and another sells singles. Some charge flat shipping and some ship free above a threshold. The only fair comparison is price per milligram. Even that needs care, because the milligrams on a label aren’t always the milligrams of peptide in the vial.

This guide covers price comparison only. It isn’t guidance on using any product.

Step 1: Price per labeled milligram

The basic formula:

cost per mg = price ÷ (mg per vial × number of vials)

Larger vials and kits usually cost less per mg, but only compare like with like: the same peptide, the same form, and prices in the same currency.

Step 2: Add what you actually pay

Shipping and fees change the answer, especially on small orders.

Free-shipping thresholds, payment surcharges and discount codes all shift the effective price. Work it out on the final checkout total, not the product page.

Step 3: Watch for blends

Blends combine two or more peptides in one vial. “Cost per mg” of a blend is ambiguous: per mg of the whole blend, or per mg of one component? Comparing a blend with a single peptide on total milligrams flatters the blend whenever the components cost different amounts. Compare blends with blends of the same ratio, or price each component separately. Our price index lists blends such as BPC-157 + TB-500 as their own products for this reason.

Step 4: Adjust for what is really in the vial

Two corrections can change the true price of a milligram of peptide.

Peptide content

A label of “10 mg” may refer to the weight of the freeze-dried powder (gross weight) rather than the peptide itself. One supplier, for example, says its peptides may be supplied by either gross or net peptide weight, and that its certificate of analysis shows which [1]. That powder also contains residual moisture and counter-ions such as trifluoroacetate and acetate. As a result, peptide content typically falls around 70–90% [1]. At 80% peptide content, a vial with 10 mg of powder holds about 8 mg of peptide, so a $4.90/mg price is really about $6.13 per mg of peptide.

cost per mg of peptide = cost per mg ÷ peptide content

Most vendors don’t publish peptide content. If two products differ by a few percent on price, unknown peptide content can easily outweigh that difference.

Measured quantity

Independent tests often report the measured amount in a vial as “mg per vial” [2], and it doesn’t always match the label. In one 2024 study of semaglutide bought from illegal online sellers, the measured content was 28.56–38.69% above the label [3]. Under-filled vials are the costlier problem for a buyer. If a test shows 9.2 mg in a “10 mg” vial, the real cost per mg is about 9% higher than the label price suggests. Overfill isn’t a bargain either: it means the label is wrong.

Common pricing traps

• Size ranges in the product name. A title like “BPC-157 5mg–10mg” often defaults to the smaller size. Check which variant the headline price belongs to before you compare.
• Bundles with extras. Kits that include accessories or “free” add-ons make the peptide look cheaper or dearer than it is. Price the peptide on its own where you can.
• Discounts that don’t apply. A sitewide code can exclude the products you want, or stop applying above a quantity limit. Check the discount on the checkout page, not the banner.
• Fees added at checkout. Card surcharges, “processing” fees or required shipping insurance can add several percent. Use the final total.
• Different forms of the same peptide. Some peptides are sold in more than one form or salt, or as modified versions, under similar names. Make sure two listings are the same compound before comparing prices. A cheaper “equivalent” may be a different molecule.
• Out-of-stock bargains. The cheapest listing is sometimes the one you can’t buy. Our index shows stock status so these don’t skew comparisons.

Step 5: Treat outliers with suspicion

A price far below everyone else’s usually has a reason: a mislabeled or under-filled product, old stock, or a store that takes payment and never ships. The FDA lists “deep discounts or prices that seem too good to be true” among the warning signs of an unsafe online pharmacy [4]. Before buying an outlier, run the six vendor checks and pay with a method you can dispute.

How our price index works

• Sources. Our price index reads the public product data that stores publish, such as the product feeds built into common e-commerce platforms. We read the product name, size, price and stock status the same way a shopper would. We never log in, add to cart or check out.
• Refresh. Prices are refreshed daily. Every offer shows the time we last fetched it.
• Parsing. We work out milligrams per vial and vials per pack from product names. Each offer carries a confidence flag (high, medium or low) so you can see when a listing was ambiguous.
• Currency. We calculate cost per mg in US dollars only for listings priced in US dollars. Other listings are shown in their original currency.
• Excluded. Prices exclude shipping, taxes, discount codes and peptide content, because we can’t observe them reliably for every store.
• Sorting. Offers are sorted by cost per mg. Affiliate relationships never change which offers appear or their order. See our disclosure and methodology.

To compare whole vendors rather than single products, see our cheapest vendors ranking, which sets each vendor’s typical price against the market median.

Price isn’t quality. The cheapest offer for a peptide may still be the wrong product, and the dearest may be no better. Pair prices with each vendor’s transparency checks and its batch COAs: third-party tested vendors lists who publishes them.