Blends & stacks

Blend versus stack

Blend

A single vial containing two or more peptides, combined by the supplier before lyophilisation. One vial, one reconstitution, one expiry — but several active components in a ratio you did not choose and cannot alter.

Stack

Two or more separately purchased compounds used over the same period. Each keeps its own vial, its own concentration, its own expiry and potentially its own schedule. Drawing two into one syringe does not make them a blend.

The distinction is not pedantry: it determines whether a change in your record is even possible. In a stack, you can change one component and see the effect against unchanged others. In a blend, every component moves together, so nothing can be attributed to any one of them.

Named blends: GLOW, KLOW and friends

The market has settled on nicknames for common combinations. GLOW is generally used for a mix built around GHK-Cu, BPC-157 and TB-500; KLOW typically adds KPV. These are supplier marketing names, not standards.

The arithmetic of a blend

A blend vial's label states a mass per component, and often a total. Reconstitution divides all of them by the same water volume, so every component's concentration is determined at once.

Worked example, arithmetic only: a vial labelled 50 mg GHK-Cu / 10 mg BPC-157 / 10 mg TB-500 reconstituted with 5 mL of bacteriostatic water yields 10 mg/mL, 2 mg/mL and 2 mg/mL respectively. One U-100 syringe unit (0.01 mL) then contains 100 mcg, 20 mcg and 20 mcg. Draw any volume and all three move together in that ratio.

That is the whole mechanic — and it is why a blend cannot be titrated component by component. Our reconstitution calculator handles multi-component vials so you can see all three figures at once instead of running the division three times.

How to log each case

If it arrived pre-blended in one vial

• Create one compound marked as a blend, with each component and its mass listed.
• Reconstitute once; the app derives every component's concentration from the same water volume.
• Each entry records one volume, and the per-component amounts are derived — not typed three times.

If they are separate vials

• Create one compound per vial, each with its own concentration and expiry.
• Log separate entries on the same date. The calendar shows them together; the data stays separable.
• Never invent a combined compound named after the pair — that is the single most damaging shortcut in peptide logging.

Most trackers force a choice: either blends are unsupported and you enter three fake compounds, or everything is one line and detail is lost. PepCycle models the blend itself, which is why the feature list calls out blends explicitly.