Hi Aplrt
I agree with Jiberish that some premenopausal women can grow while taking PM for 3 weeks or more per cycle without BC, but I'm personally only aware of one. There may be others, but they must be very much in the minority if I haven't come across them. Usually premenopausal women mess up their cycles, get estrogen dominance symptoms, and don't grow at all when they attempt to take PM for 3 weeks or more per cycle.
Of course, you could just forget about the PC and take PM continuously, all month long, with a BC that's high in estrogen and progestin. It's cheap, it's easy, and it worked extremely well for Jiberish's partner, as well as MydreamisGcup and IdreamofD. They were also some of this boards fastest growers. It's not yet clear if this method works for all healthy young women, but what on earth does? If you decide to try their method, than you can ignore everything else that I'm about to say, since it'll be completely irrelevant.
Typically, premenopausal women who are not on BC will cycle PM by taking it internally only until ovulation. It might be even better to stop taking it internally one or two days prior to ovulation. The cream is usually used twice per day throughout the entire cycle, but you should probably start with the minimum dose. There are also a lot of women who take PM pills even less then 13 days per month. In that case, they normally don't take it during their period, or at least not during the first half of their period, usually because of increased cramping or bleeding, but not everyone gets these side effects.
If you decide to use progesterone, you should use it in the form of a bio-identical progesterone cream, aka PC. Avoid all the creams that don't say "bio-identical" or that don't list the number of milligrams of actual progesterone on their packaging or site. Emerita Pro-gest is a popular brand of PC, but I don't know if you can get it in your country. Keep in mind that it's MUCH worse to use too much PC than it is to use too little, and it's very easy to accidentally take too much. If you overdose on it severely (which is apparently not difficult to do), it can stop your growth for anywhere from a few months to a year, mainly because large amounts of excess PC can get stored in fat tissue and continue releasing into your blood stream like a time release capsule for a very long time.
You have 2 options when it comes to PC dosing, but neither has been tried by enough women to be considered a "sure thing". Option one was tried by a member named Ginie who grew very well by taking PC during her entire luteal phase, but only when her BBT charts and cycle length indicated that it was needed. It's worth pointing out that Ginie had a real, diagnosed progesterone deficiency, which means that it would have been difficult for her to take too much progesterone. That puts her in a very different position than most healthy young women. Option 2 was tried by an apparently healthy young woman who did not have any hormonal issues that she was aware of. She did not keep track of her hormones at all, and she used PC for only 2 or 3 days per month. I don't remember her username, and her program ended a very, very long time ago. The fact that I had to dig so deep into the past should tell you how rare it is for a completely healthy women to succeed while using PC. On the other hand it's also extremely rare for a premenopausal women who is not on BC to successfully grow and keep her growth while taking PM alone, without having to continue taking a "maintenance" dose of PM. Most don't even get to the stage where they would need to take a maintenance dose of PM, because their swelling disappears after every single period, without increasing from month to month.
To sum it up, you can either take a tiny amount of PC every month or you can use BBT (basal body temperature charting), possibly along with blood tests, to figure out when to use PC cream. The second option is probably trickier and more likely to fail, mainly because even if you know EXACTLY what your hormone balance is like, unless you have a progresterone deficiency, it won't be at all clear how much PC you should take to balance out the PM. I myself am taking a huge risk by trying to use BBT to figure out when and how to take PC.
People often point out that there are some women who grew while using large amounts of PC for long periods of time, either with or without PM. However, as far as I know, every last one of these women had a diagnosed hormonal disorder known to cause progesterone deficiency. Even some women with a diagnosed progesterone deficiency did not grow at all on PC, or stalled out after an extremely small amount of growth.
You could also avoid PC entirely, and instead just cycle PM with herbs during the second half of your cycle. Chiyomilk is the poster girl for this method. She may be the most successful biologically female grower this board has ever scene, although she was not actually a member of this board. She used a low dose herbal pill called B-up during luteal phase. It probably worked mainly by raising progesterone and/or prolactin, and it contained only a small amount of phytoestrogens. Rather than using B-up, which is extremely expensive and not available to all countries, some people are now experimenting with using the Greenbush combo during their luteal phase. If you want to play it safe you can take only a low dose of herbs, but it's not clear how much of the Greenbush combo you can take while cycling it with PM. It's possible that a larger dose would work even better, but it might also cause stalling, and B-up contains only a very small amount of similar herbs.
I never meant for this post to be so long
On the other hand, putting it all in writing really cleared up a lot of lingering confusion in my own mind, so thanks!