Hormonal FDA-approved medicineControlled substance

Testosterone Cypionate

Test C · Test Cyp · Depo-Testosterone

Evidence: Approved label. Example dose: finalize with a provider. Not a fact-check stamp.

100-200mg – 15-25 mg SubQ Every 1-2 weeks (IM) or 2x weekly (SubQ)

50-70 mg per dose – 100-200 mg IM 2x Weekly

Testosterone cypionate is a synthetic esterified form of testosterone, the primary male androgen. The cypionate ester (cyclopentylpropionate) is attached to the 17-beta hydroxyl group, creating a depot formulation that slowly releases testosterone after intramuscular or subcutaneous injection. It was first introduced in the 1950s and has been a mainstay of testosterone replacement therapy (TRT) for decades.

Quick Start

Route

Intramuscular (IM) or Subcutaneous (SubQ)

Start low

100-200mg SubQ

Frequency

Every 1-2 weeks (IM) or 2x weekly (SubQ)

Timing

No specific requirement

IM or SubQ injection. Consistent timing (same days each week). Many prefer morning injection. Pin alone.

❋

Start here. Every protocol below is ordered lowest-first. Begin at the smallest effective dose, hold about a week to assess tolerance, and step up only if needed.

Tiered Protocols · lowest first

Conservative start

100-200mg · Intramuscular (IM) or Subcutaneous (SubQ) · Every 1-2 weeks (IM) or 2x weekly (SubQ)

conservative starter

100-200mg

Every 1-2 weeks (IM) or 2x weekly (SubQ)

Intermediate

Split TRT (Stable Levels)

50-70 mg per dose · IM · 2x Weekly

anecdotal · community

Splitting flattens peak/trough swings, reducing aromatization and hematocrit spikes vs a single weekly shot.

50-70 mg per dose

2x Weekly

Standard

Standard TRT (Weekly IM)

100-200 mg · IM · Weekly

human study · Endocrine Society guideline (Bhasin et al. 2018, J Clin Endocrinol Metab)

Check trough before the next shot. Monitor hematocrit, estradiol, PSA, lipids.

100-200 mg

Weekly

Expert

SubQ Micro-dose

15-25 mg · SubQ · Every other day

human study · Al-Futaisi et al. 2006 (Saudi Med J)

Frequent small SubQ doses give very stable serum levels and often lower hematocrit/estradiol. Uses insulin syringes.

15-25 mg

Every other day

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How it works

Binds to intracellular androgen receptors, translocating to the nucleus to activate transcription of androgen-responsive genes governing muscle protein synthesis, bone mineralization, erythropoietin production, and secondary sexual characteristics.

Aromatized to estradiol via aromatase enzyme, contributing to bone density maintenance, lipid metabolism, and CNS function. Also 5-alpha reduced to dihydrotestosterone (DHT) in peripheral tissues, mediating androgenic effects on skin, hair, and prostate.

Suppresses hypothalamic GnRH and pituitary LH/FSH secretion via negative feedback, which is why exogenous testosterone suppresses endogenous production and spermatogenesis.

What to expect

Early

Days 1–7

Days 1-14: Initial mood and energy improvements; libido may increase. Testosterone levels peak 24-48 hours post-injection then gradually decline.

Evidence

HumanStrong

AnimalPresent

In-vitroPresent

References for this compound are being re-checked against their source records. We are not showing them until each one is confirmed to support the claim it sits under.

Interactions & stacking

Two different questions: what is documented about running these together, and what is documented about drawing them into the same syringe. A good pharmacological partner can still have to be pinned separately.

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Pin alone. Testosterone Cypionate must not share a syringe with anything else, whatever the pharmacology says. Oil-based depot - never mix in same syringe with aqueous peptides. Always use separate syringes and needles.

Documented together

AnastrozoleAromatase inhibitor manages estrogen levels during TRT. Titrate to E2 lab values.

EnclomipheneSERM can be used alongside low-dose TRT to maintain LH/FSH. Not for concurrent high-dose use.

GHK-CuGHK-Cu supports collagen and tissue repair. Separate syringes (oil vs aqueous).

IpamorelinGH secretagogue complements testosterone for body composition. Separate syringes.

Keep separate

TriptorelinGnRH agonist used for PCT after steroid cessation, not during active TRT.

Check any specific pair in the Stack & Interaction Checker, which answers both questions separately. Absence of a documented conflict is not evidence of safety.

Pharmacokinetics

Illustrative plasma concentration · 34 d

Half-life

~8 days

Ester

Peak · Tmax

24-48 hours

IM; 12-24 hours SubQ

Elimination

~40 days

~5x half-life

Bioavailability

~100%

IM/SubQ (oil depot, complete absorption)

Duration of action

10-14 days

Per injection (supports weekly or biweekly dosing)

Clearance

Hepatic (CYP3A4, CYP2C9); ester cleaved by tissue esterases releasing free testosterone

Storage. Store at controlled room temperature 20-25C (68-77F). Protect from light. Do not refrigerate or freeze (may crystallize in oil). Warming the vial before injection can ease administration.

Regulatory status

FDA-approved (Schedule III controlled substance). Indicated for testosterone replacement in males with conditions associated with deficiency or absence of endogenous testosterone.

Put it to work

Calculate, log & track

Open Testosterone Cypionate straight into OnePin with your vial and dose pre-filled, then let it handle the syringe math and remind you before the vial runs out.

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Go deeper

The guide & community

The complete Testosterone Cypionate walkthrough, real protocol discussion and coaching live inside the BlessUp community on Skool.

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