Peptide FAQ — Dose Calculator, Safety, Legality, Storage

Question 1

What are peptides?

Accepted Answer

Peptides are short chains of amino acids — typically between 2 and 50 residues — linked by peptide bonds. They occupy the middle ground between single amino acids and full proteins, and act as signaling molecules (hormones, growth factors, neuropeptides) or as research tools that mimic portions of larger endogenous proteins.

Question 2

What's the difference between a peptide and a protein?

Accepted Answer

The distinction is size and structure. Peptides are short (typically <50 amino acids) and often lack stable tertiary folding. Proteins are longer (typically >50 residues) and fold into defined three-dimensional structures. The boundary is conventional rather than biochemically absolute — there is no precise molecular-weight cutoff.

Question 3

How do I use the peptide calculator?

Accepted Answer

Enter three numbers: (1) the peptide content per vial in mg, (2) the volume of bacteriostatic water you are reconstituting with, and (3) your target dose. The calculator returns the draw volume in milliliters and the equivalent number of units on a U-100 insulin syringe.

Question 4

How are peptides injected?

Accepted Answer

Most peptides are administered subcutaneously using an insulin syringe — the fat layer of the abdomen, thigh, or buttock is the standard site. Draw the calculated volume, inject at a 45–90° angle, and rotate sites to avoid local tissue changes.

Question 5

Are peptides legal?

Accepted Answer

It depends on the peptide and jurisdiction. FDA-approved peptides (semaglutide, tirzepatide, tesamorelin) are prescription drugs. Research peptides (BPC-157, TB-500, CJC-1295) are legally sold for laboratory research use only in most countries; self-administration for human use is not FDA-approved. Regulations vary by country and continue to evolve — in 2023 the FDA added several peptides to its section 503A compounding list.

Question 6

Are peptides safe for people under 18?

Accepted Answer

Peptide use in minors is outside the clinical-evidence base for virtually every peptide discussed on this site. Endogenous growth-hormone axis amplification during natural growth years can produce unintended consequences; GLP-1 approvals for adolescents exist but are limited to specific clinical indications. Peptide use by minors without medical supervision is not supported by evidence.

Question 7

How important is sterility when handling peptides?

Accepted Answer

Critical. Any injection bypasses your skin's immune barrier. Poor technique can introduce bacteria, fungi, or particulates into the bloodstream or subcutaneous space — causing abscesses at best, systemic infection at worst. Always use fresh needles, wipe vial stoppers with alcohol, and discard solutions that appear cloudy, discolored, or particulate.

Question 8

How should I store peptides?

Accepted Answer

Lyophilized (powder) peptides are typically stable at room temperature for months, but refrigeration extends shelf life. Once reconstituted with bacteriostatic water, most peptides are stable for 21–30 days at 2–8°C. For longer storage of reconstituted peptide, aliquot into small single-use vials and freeze at −20°C or below.

Question 9

Do GLP-1 drugs cause muscle loss?

Accepted Answer

All rapid weight loss — whether from GLP-1s, VLCDs, or bariatric surgery — involves some lean-mass reduction. DEXA analyses of GLP-1 trials report roughly 25–40% of weight lost is lean mass, in line with other forms of caloric deficit. Adequate protein intake (1.6–2.2 g/kg body weight) and resistance training attenuate this effect substantially.

How do I use the peptide calculator?

How are peptides injected?

How should I store peptides?

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