Test and primo are a great combo.
Would adjust the ratio based on bloodwork.
Primo has an AI effect so you may need to raise your test dose to have E2 in desired range.
Generally recommended to run at around a 1:1 ratio.
Sarms like MK would be pointless, it's weaker in its effects and may outcompete with AR receptors with your other compounds & even at 25mg it will likely skew your blood work and lipids so it's not benign.
Var would be a much better choice if you need a pre workout boost.
It also has benefits for collagen synthesis and anti cortisol effects so it will help with joints.
Lower doses like 10-20mg can be effective and at that dose can be run for longer with less negative effects.
With higher doses just might need to limit the duration if you want to keep all your health markers in check.
Cardarine is okay also.

I’m practically doing the same cycle minus the Mk. But I will run mine for 20 weeks.

Not sure if you are stuck on primo… but subbing it with NPP and upping the test could be fun and you could stay at the 12 week range… then run the var on the back end. The world is your oyster if diet is good.

I dont want to hijack the thread but since you are asking about similar compound that i plan this summer, might as well ask here. Does anyone have experience with test-c, anavar cycle? I never tried anavar, and i thought about doing test-c 500 mg/week, anavar 210-350 mg a week? I will be starting cycle as single digit bf and looking to get lean gains with strength added. I tried masteron in past but not winstrol, thought about winnie but my joints are already dry as it is, so i want to avoid it. Hairloss doesnt happen to me so its a non issue.

• I’d drop the var completely unless you’re using it on the back end of a deep cut where you get to real low body fat. Otherwise, it’s an overrated drug with how much it trashes your lipids. I mean it absolutely wrecks them. People also say use var because it’s “liver safe” since it’s metabolized through the kidneys instead of liver. Well the liver can regenerate from damn near anything, but your kidneys not so much. Protect those kidneys man no one wants to be on dialysis. Take your organ support supplements when running your cycles and especially on orals.
• I’m not in the camp of saying you have to run X mg of Y compound to see any benefits. You get extra muscle growth from any amount of extra gear in your system if your diet and training is sufficient. So I have no problem with 300 test and 400 primo as your first cycle with multiple compounds. It’s safe dosages and, being your first cycle, the point is lowest dose to achieve results. As was said below though, I would suggest pushing a test/primo cycle to the 16-20 week mark.
• I never got joint benefits from ostarine/mk-2866. Had slightly higher free test from it though. Once you’re running legit gear, I don’t really see the point of throwing in SARMs too. I’d spend the money on more gear like proviron. But if you like it, then go for it. Not a big deal on this one.
• No issues with cardarine. Helps lower LDL and raise HDL. Gives an insane boost to endurance. Some cancer studies on it that could cause some folks to be weary.

Good luck and have fun with the cycle.

primo is a waste at 12 weeks, run it out to 16. its extremely slow acting. it doesnt start to get good until week 12. your leaving alot on the table stopping that short. also up the primo, its from what I gathered 1/3 strength of test. 400 will yield little other than a hole in the wallet, I'd recommend at least 350 test 600 primo because 600 is too high for 300 test, you'll have low e2. also if you switch to 16 just move your anavar start week much later which I'm sure you know