Primo ratio question

I'd go with a 2:1 Test to Primo ratio.

Primo generally needs to be run fairly high. Everyone's different, but I'd recommend Test at 500 mg/wk and Primo 500–600 mg/wk. I wouldn't start low and ramp up — Primo really needs at least 16 weeks to shine, and starting low just delays the results you're after.

It's not cut-and-dry since people aromatize differently. Some guys do 1:1 Test:Primo and feel fine; others need Primo closer to half their Test dose or they get low-E2 sides. Factors include your aromatization rate, body fat, total androgen load, and bloodwork. Also, there's a pro bodybuilder, Paul Barnett, who sells a cycle design cheat sheet for around $30 — could be worth picking up if you want more clarity on ratios and cycle structure.

Thanks — I actually have that cheat sheet. I'm mostly trying to get a ballpark of what others run. I'll experiment, then get bloods.

Yeah, I'm leaning toward that ratio. Thanks for the tip.

I'd mirror the EQ ratio you used and tweak from there based on how you feel and labs.

I'm another high Test-to-E2 converter. I began at 1.5:1 Test to Primo to see how I'd react, then settled at 1.25:1. That kept my E2 in the low 50s, which I prefer.

Exactly — that approach works.

Makes a lot of sense and keeps me below a 1:1 split. Good plan.

Thanks everyone, that's helpful. Good to hear other people's experiences.

I wouldn't call myself a hardcore Primo user but I've run maybe 10–15 vials. Never finished a full bulking Primo cycle — I stopped around week nine at roughly 700 mg/wk and didn't notice much. I figure if I'd stuck with it longer I'd have seen results; I probably quit right when it was starting to act. Life and money got in the way so I won't half-ass it again. I ran Test at 500 mg/wk and felt great. Next time I'll try Primo around 1000 mg/wk with Test at 750 mg. People aren't lying about how mild and slow it is. That said, it's exceptional for cutting and preserving muscle on a calorie deficit — nothing else I've used beats it for that, in my opinion.

Nice — I'm using Primo for a cut. EQ served me well for the bulk. I'm going to start 1:1 Test to Primo and see how it goes, then adjust after I get bloods. Thanks for the input.

It's fantastic for cutting. During a half-hearted bulk attempt I went a week on stimulants and barely ate — missed the gym — and still didn't lose muscle. Strength barely dropped, if at all. I kept Primo dosing even while neglecting diet/training. I tried a low maintenance dose once (about 350 mg/wk) to see how little I needed and that seemed to hold muscle in a deficit. I'm stocking some for the summer and plan to run 350 mg/wk; there will be slack days but it still works great. I have a fast metabolism and usually shed mass quickly if I stop eating/training — Primo felt like a muscle preservative.

I agree — start at the doses you plan to run. I'm on my second Primo cycle. First time I did 1:1 (700 Test / 700 Primo) at about 12% BF and an ultrasensitive E2 test showed my E2 crashed to 12. Switched to 2:1 and that corrected it, though it's hard to say how much muscle that added. On my current cycle I'm at 850 Test, 280 Primo, and 450 Deca — week three and things feel like they're kicking in. Planning to run up to 24 weeks. Unless I bump Test way higher, Primo is a safe pick for keeping E2 manageable and adds a bit of anabolism to the stack.

A 1:1 split wrecked my E2 — I'm a big aromatizer. I preferred Primo at around 80% of my Test. 750 Test / 600 Primo was perfect for me (about 1.25:1), I could even run 1.3:1. Primo's my go-to secondary. With EQ I had similar issues: unless I ran EQ high alongside high Test, I'd convert too much to E2. Low Test and low EQ pushed my E2 up.