Just finished a 20-week test and Deca blast, here is whether the extra 4 weeks actually did anything

[Davo]

Ran test E 500mg plus Deca 350mg for the full 20 weeks this time. Previous two blasts were 16 weeks with the same stack. Honest assessment: yes, weeks 17-20 added something. Not dramatic but real. Conditioning improved noticeably in that final month and joint improvement from the Deca kept building. Recovery is the trade-off - adding 4 weeks to the blast added roughly 3-4 weeks to full recovery. Worth it if your calendar has space for it, not if you're trying to get PCT done before a specific deadline.

[Beantown Rick]

The extra weeks are compound-specific, not universal. Deca and EQ are the two where extending to 20 weeks is clearly justified because they're still producing changes through weeks 16-18. Test E at 16 or 20 makes minimal difference since it reaches steady state early and you're not gaining anything from the extra weeks on test alone. If Deca is your primary anabolic the maths strongly support running it longer.

[CapeTown CT]

Ran a 20-week test and Deca cycle last year, first time extending past 16. The final 4 weeks were still productive - not dramatically so but the joint improvement from the Deca kept building and conditioning continued to improve. Recovery was the trade-off. Adding 4 weeks to the blast added roughly 3-4 weeks to full recovery which pushed my PCT timing into a period I hadn't planned for. Worth it if the calendar allows, not if you have a fixed end date.

[TEXMEX]

20 weeks with Deca is right, 16 weeks you're basically cutting it off just as the compound hits its best window. I've run both and the difference in final conditioning at week 20 versus week 16 on the same stack is visible. The longer clearance time post-blast is the only real cost and if you plan for it it's manageable. 20 weeks with test E plus Deca, 3 weeks after last pin before PCT starts, 4 weeks PCT. Total timeline is about 27 weeks from first pin to PCT complete.

[Geoff K]

This answers a question I've had for a while. I've always run 16 weeks with test only and wondered if I was missing something by not going longer. The answer is no for test-only, yes if you're running Deca or EQ. That distinction makes the whole debate make sense now.

[ScouseLad]

this is way too advanced for me right now but bookmarking it for when i get to that stage. good to know deca needs the longer run to do its thing properly. explains why some lads say their first deca cycle did nothing - probably bailed too early

[NYCgains]

20 weeks is right if Deca is in the stack. The math on effective weeks is compelling - at 16 you're getting maybe 11-12 effective weeks after the build-up period. The extra 4 weeks is a real difference in compound output not just time served. Recovery planning around the longer clearance is the main adjustment.

[CaliBro]

20 weeks with Deca is the right call. West coast competitors who've been doing this for years are mostly running 20 minimum when Deca or EQ is in the stack. The 16-week habit came from people running short ester cycles where it makes sense - applied to long ester slow compounds it's just cutting the cycle off before you get the best of it.

[OhioStrong]

Saving this thread for when I get to planning cycles with Deca. The compound-specific logic for going longer makes total sense. Wouldn't have known to run Deca for 20 weeks without reading this - would probably have stopped at 16 and wondered why it underperformed versus what people report.

[BERLINER]

The argument for 20 weeks with slow compounds is supported by the pharmacokinetic data. Undecylenate and decanoate esters both require 4-6 weeks to reach true steady state. A 16-week blast with Deca gives approximately 10-11 weeks at peak blood levels. A 20-week blast gives 14-15 weeks. The additional suppression recovery time is the real cost - this must be factored into cycle planning.

[MunichMarc]

The 20-week argument is convincing for Deca cycles. In Germany I can plan cycle timing more flexibly so the extended recovery period is manageable. Will apply this on my next Deca run rather than cutting at 16 weeks as I did previously.

[SWE LIFTS]

The pharmacokinetic argument for 20 weeks on Deca or EQ is solid and matches my experience. Ran a 20-week EQ cycle and the compound was still visibly working in weeks 16-18. Cutting at 16 would have missed the best conditioning weeks. Recovery planning is the key variable - I book the 3-week clearance period into my calendar before I even start.

[OsloFit]

This explains a lot. I was planning a first Deca cycle at 16 weeks without understanding that the compound needs more time than that to produce its best effects. Will adjust the plan to 18-20 weeks. The recovery timeline extension is something I will build into the schedule from the start.

[Paris GH]

The argument for 20 weeks on slow compounds is well made. I have typically run 16 weeks out of habit but the pharmacokinetic case for extending when Deca is the primary anabolic is convincing. Will apply this on my next cycle. The recovery timeline is something I can plan around with enough advance preparation.

[HighAltitude]

The effective weeks calculation is really helpful for planning. At 16 weeks with Deca you're basically getting 11-12 weeks of peak levels after the build-up period. At 20 weeks you're getting 15-16. That's a 30-40% increase in effective compound exposure just by extending 4 weeks. Will plan my first Deca cycle at 20 weeks from the start rather than learning this after.