How to Read a Peptide Pen Dial

📅 June 19, 2026 ⏱️ 3 min read ✍️ Team TPS

The commonest peptide pen mistake is assuming a unit means the same thing on every pen. It does not. A unit is a volume on the dial, and what that volume contains depends entirely on the concentration of the pen you are holding.

What a unit actually is

A pen’s dial measures volume, not compound. When a manufacturer puts 10mg of a peptide into a 200 unit pen, each unit carries 10mg ÷ 200 = 50mcg. Put the same 10mg into a 300 unit pen and each unit carries 33.3mcg.

Same milligrams. Same peptide. Different amount per unit. This is why “I run 15 units” is a meaningless statement without naming the product.

Reading a product’s figures

Every SerenQ product page lists four numbers, and together they tell you everything:

Total content, the milligrams in the pen.
Total units, how many units the pen holds (200 or 300).
Dial graduation, what a common increment delivers.
Per unit, the amount in a single unit.

Work from the last one. If you know your target dose in mcg or mg, dividing by the per-unit figure gives you the number to dial. Do not carry a unit count across from a different product.

A worked example

Take SerenQ BPC-157 10mg, 10mg across a 200 unit pen, so 50mcg per unit. A 250mcg target is 250 ÷ 50 = 5 units.

Now SerenQ Tesamorelin 10mg: the same 10mg, but across 300 units, so 33.3mcg per unit. The same 250mcg target is 250 ÷ 33.3 = roughly 7.5 units.

Identical milligrams in the pen, and a 50% difference in the number you dial.

Blends complicate the arithmetic

In a blended pen every unit delivers all the components at once, in the ratio set at manufacture. SerenQ GLOW carries BPC-157 10mg, TB500 10mg and GHK-Cu 50mg in a 300 unit pen, so one unit delivers 33.3mcg, 33.3mcg and 167mcg respectively.

You cannot dose one component of a blend independently. If you need to, run the singles instead.

Why pens are still simpler than vials

All of the above sounds like maths, but it is arithmetic you do once, from figures printed on the page. With a vial you also choose the dilution, which means the per-unit figure is something you create rather than read, and an error there silently affects every dose after it. See peptide pens vs vials.

Supplied for research purposes only. This article is informational and is not medical advice.