Cost per milligram: how to compare peptide suppliers fairly

The formula

1. Price per vial = kit price ÷ vials per kit.
2. Landed cost per vial = price per vial + (shipping + duties + other costs on the order) ÷ total vials on the order.
3. Cost per mg = landed cost per vial ÷ mg per vial.

Example: a $44 kit of ten 10 mg vials is $4.40 per vial. If shipping and duties add $60 to an order of 100 vials, that is $0.60 more per vial, so $5.00 landed, or $0.50 per mg. The cost-per-mg calculator does this for any sheet line.

Why per-mg changes the answer

Suppliers price strengths very differently. Some charge almost the same for a 5 mg and a 10 mg vial, which makes their larger vials far cheaper per mg. Others price almost linearly. Comparing by vial hides that; comparing by mg exposes it.

In this example B is cheaper for 5 mg and A is cheaper for 10 mg. The practical rule many suppliers land on is to buy each product and strength from whoever is cheapest for that exact line, not to pick one supplier for everything.

Normalise the price sheet before you compare

• Separate blends from single compounds. A blend line that contains a compound's name is not the same product.
• Watch the unit column. IU, mcg and ml lines cannot be compared per mg without a conversion, so keep them in their own group.
• Confirm the currency. Sheets without a currency printed are a common source of 7x mistakes.
• Check whether the listed price is already discounted, and against what.
• Keep old prices when a new sheet arrives, so you can see what changed.

Price is not the only column

The cheapest line is only a good buy if the batch passes testing. Track, per supplier:

• Share of batches that passed your release rule the first time.
• Average purity on your own lab reports versus the supplier's paperwork.
• Lead time from order to arrival.
• Whether they answer questions and fix problems.

A supplier who is 10 percent cheaper but fails one batch in five is not cheaper. See building a lab report library.

Turning the comparison into purchase orders

1. Build a board: every product and strength, every supplier, cheapest landed cost first.
2. Build a cart across suppliers from the board.
3. Split it into one purchase order per supplier.
4. Record shipping and duties when you know them, so landed cost per vial is accurate.
5. When the order arrives, receive it as new batches in quarantine with the cost already filled in.

A worked comparison

Three sheets quote the same compound at 10 mg:

On headline price C looks most expensive and B cheapest, and here that holds. Change the order size and the shipping share changes with it, which is why landed cost has to be calculated per order, not assumed.

One more habit worth keeping

Run the numbers in the currency you sell in, on the day you place the order, and keep a note of the exchange rate used. When a supplier quotes in another currency, the rate on the day the payment clears is the one that counts, and a move of a few percent can erase the gap between two close quotes. Build that uncertainty into the comparison rather than discovering it afterwards.

Blends and multi-compound vials

Vials that contain more than one compound cannot be compared on a single per-mg figure. Compare them against the cost of buying each compound separately at the same amounts, and against other blends with identical contents. Never let a blend sit in the same comparison row as a single compound, because the per-mg number will look cheaper than it is.

Worked example with shipping and duties

A supplier quotes $60 per kit of 10 vials at 5 mg. You order 20 kits. Shipping is $85 and duties and brokerage come to $65, so $150 of order costs over 200 vials.

• Price per vial: $60 divided by 10 = $6.00.
• Order costs per vial: $150 divided by 200 = $0.75.
• Landed cost per vial: $6.75.
• Landed cost per mg: $6.75 divided by 5 = $1.35.

Order 10 kits instead and the same $150 is spread over 100 vials, adding $1.50 per vial, and the per-mg cost rises to $1.50. Order size can move the answer as much as the quote does, which is why the comparison should be run on the order you actually plan to place. The cost-per-mg calculator does this arithmetic for you.

Mistakes that make a sheet look cheaper than it is

• Reading a kit price as a vial price, or the other way around.
• Comparing a 5 mg vial price with a 10 mg vial price without converting.
• Leaving out shipping because it is quoted separately.
• Forgetting duties and brokerage fees on imported orders.
• Ignoring minimum order quantities that force you to buy more than you can sell before retest.
• Comparing prices in different currencies without converting at the day's rate.

Setting a sell price from landed cost

Once you know landed cost per vial, price each product from it, not from what a competitor charges. Decide the margin you need to cover testing, packaging, payment fees and your time, then check that the result is a price buyers will pay. If it is not, that product may not be worth stocking from that supplier.

Recalculate when a supplier changes price or shipping costs move. A price that was right six months ago can quietly turn into a loss.

Keep the history

Save every sheet you receive with its date. Over a few months you will see which suppliers hold prices, which raise them after a first order, and what a fair price for each compound looks like. That history is your leverage in the next negotiation.

Doing it in Purity

Purity imports supplier price sheets, converts every line to cost per vial and per mg, keeps price history, and shows a board with every supplier cheapest-first for each product and strength. One cart becomes a purchase order per supplier, landed costs are spread across vials, and received orders arrive as quarantined batches. See it on a demo.