What is Test/Deca Mix 500?
Test/Deca Mix 500 is a ready-made oil solution with 300mg testosterone enanthate and 200mg nandrolone decanoate (Deca) per ml, 500mg/ml in total. One vial holds 10 ml and needs no mixing. Both esters are long, so two injections per week are enough for steady levels.
The pairing is one of the oldest in strength sports: testosterone as the base, nandrolone as a second building compound. Nandrolone decanoate was approved as a medicine against muscle wasting and anemia. The 3:2 ratio in the blend means there is always more testosterone than nandrolone in play.
This information is for research and educational purposes only. No medical advice.
Comparison
Two esters in one oil
Components and related blends at the same receptor, as stated in the TPD lexicon. Tap a card to open its entry.
Simplified: both esters are long, so the blend keeps acting for a long time. The amounts of both compounds are locked together. 1011
How it works
Both compounds activate the androgen receptor in muscle and drive protein synthesis, nitrogen retention and recovery. Nandrolone lacks one methyl group (a 19-nor steroid), which makes it strongly anabolic but weaker on the androgenic side in tissue than testosterone. Many users also report fewer joint complaints, though that has not been studied properly.
Nandrolone acts noticeably on the progesterone receptor and can raise prolactin, while testosterone aromatizes to estradiol. Enanthate has a half-life of about 4 to 5 days, decanoate about 6 to 12 days. Nandrolone metabolites remain detectable for many months after the last dose.
Where it acts
Where the components acted in studies
Tap a point or a card. Grey = observed in studies, data from studies with one component or with users.
- Hypothalamus and pituitary
LH and FSH fell quickly after the first testosterone injection7
Observed in trials - Skeletal muscle
Muscle size and strength rose, most with training1
Observed in trials - Heart
Weaker pumping function and more plaque in long-term users5
Observed in trials - Liver and blood lipids
HDL fell sharply on several steroids, barely on nandrolone alone4
Observed in trials - Testes
Sperm production stopped in 65 percent on testosterone, recovered within months after stopping6
Observed in trials
Targets in the ChEMBL database10
Compound CHEMBL1200335, CHEMBL1200946: one recorded mechanism, Agonist, direct binding (both compounds).
- Gene
- AR
- UniProt
- P10275
- ChEMBL
- CHEMBL1871
- Action
- Agonist, direct binding (both compounds)
Use and dosing
Dosing
Dosing, titration and syringe
Loading the dosing information …
- Getting started and stepping up, drawn as a staircase
- Units on the U-100 syringe for every step
- How long one vial lasts
Injection
The blend is given intramuscularly, usually into the glute, thigh or shoulder. Use a thicker needle to draw up and a thin one (23G to 25G) to inject. Disinfect the stopper and the site first and rotate sites regularly.
Both esters are long, so subcutaneous injection into belly or thigh fat is possible in principle at small volumes (up to about 0.5ml per site). The high concentration can sting a little. If redness, pain or lumps appear, go back to intramuscular injection.
What the research shows
Supraphysiologic testosterone increased muscle size and strength in healthy men within ten weeks (Bhasin, 1996). In randomized trials nandrolone decanoate raised lean body mass in dialysis patients (Johansen, 1999) and in HIV-positive women with weight loss (Mulligan, 2005), each time at low medical doses.
In strength athletes 200mg nandrolone per week on its own barely changed lipids, while several steroids at once lowered HDL sharply (Hartgens, 2004). Long-term users show weaker heart pumping function and more coronary plaque (Baggish, 2017). There is no study of the fixed combination, so expectations are derived from the single compounds.
Study results
What the trials measured
Interactive: switch tabs, tap points, show or hide arms. Arms are named relative to each other, no dosing advice.
Strength gain after 10 weeks1
43 healthy men, weekly testosterone enanthate or placebo, change in kg
The abstract gives no figure for placebo with training. Mood and behaviour did not change in any group. Study with testosterone alone, not with the blend.
Lean mass on nandrolone decanoate23
Gain in kg, randomised trials against placebo
Low medical doses, not the blend. In the dialysis patients the walking and stair test also got faster while grip strength did not change. For the women the abstract gives no placebo figure; the difference was clear.
HDL cholesterol on several steroids4
19 strength athletes, self-chosen steroids over 8 to 14 weeks, not blinded
Six weeks after stopping HDL had not yet recovered. In a second, blinded study nandrolone decanoate alone did not change HDL or the other lipids over 8 weeks.
Left ventricular pumping function5
Ejection fraction, 140 experienced weightlifters, cross-sectional
Those on steroids at the time of testing were at 49 percent, those off-drug at 58 percent. Users had more coronary plaque, more with a higher lifetime amount.
Research status
Where the research stands
There is no study of the finished blend. Shown are registered trials with nandrolone decanoate; the trials on testosterone enanthate are in its own entry. As of 25 Oct 2026. 9
- Preclinical Testosterone enanthate in an animal model (monkeys)
- Phase 1 no registered trial
- Phase 2 4 trials on components, 2 completed, 1 stopped early
- Phase 3 no registered trial
- Approval no study of the blend itself
Show all 7 trials on a timelineHide timeline
NCT00242463 · 20 participants (planned), started Oct 2005, stopped early Oct 2007.
NCT02055456 · 20 participants, started Feb 2014, primary endpoint reached Feb 2017.
Registry entry ↗ · Results not yet in PubMed
HIP-SAP · NCT03545347 · 29 participants, started Sept 2018, primary endpoint reached May 2020.
Registry entry ↗ · Results not yet in PubMed
SARKOPENIA · NCT05978206 · 168 participants (planned), started Aug 2023, primary endpoint planned Dec 2026.
Le-Na · NCT02376309 · 30 participants, started Aug 2015, primary endpoint reached Aug 2016. Tests several agents.
Registry entry ↗ · Results not yet in PubMed
NCT03263520 · 60 participants, started Feb 2016, primary endpoint reached Aug 2017. Tests several agents.
Registry entry ↗ · Results not yet in PubMed
ASCEND001 · NCT07568574 · 60 participants (planned), started Mar 2026, primary endpoint planned May 2028. Tests several agents.
Bar: start to primary endpoint (planned for running trials). Green = completed, blue = progress until 25 Oct 2026, grey = stopped early.
Side effects
- Prolactin: nandrolone can raise prolactin. Typical signs are libido and erection problems, rarely milky discharge from the nipple. Prolactin therefore belongs in the bloodwork.
- Lipids: HDL falls and LDL rises, more so together with testosterone than with nandrolone alone.
- Blood pressure and heart: water retention and rising blood pressure are common. Over the years pumping function suffers. Measure blood pressure regularly.
- Sleep and mood: some report restless sleep, night sweats or low mood, often linked to prolactin and estradiol.
- Estrogen and blood count: testosterone aromatizes, gynecomastia is possible. Hematocrit rises.
- Hormone axis: nandrolone suppresses your own axis especially strongly and for long, recovery after a cycle often takes months.
Because the blend acts for a long time, side effects cannot be switched off quickly. That is why a low start makes sense.
Storage
Store at room temperature, in the dark and in the original packaging, out of reach of children. Do not put it in the fridge, because cold makes the compounds crystallize out of the oil. If you see crystals, warm the vial in your hand or in warm water and swirl until the solution is clear again. Disinfect the stopper before every draw.
