Semax Cycle: Schedules, and the Maths Beneath

Three numbers determine how long any container lasts: the usable volume in it, the volume removed per session, and the number of sessions per day. Divide usable volume by volume per session to get withdrawals, then divide withdrawals by sessions per day to get days.

That is the whole model. The interesting part is that usable volume is never the labelled volume, and the difference between the two is larger in the spray branch than most buyers expect.

Assume a bottle stated to hold 3 mL containing 3 mg, which is 1 mg per mL, fitted with a pump rated at 0.1 mL. Nominal yield is 3 divided by 0.1, which is 30 strokes of 100 mcg each.

Two subtractions follow. Assume three priming strokes to draw liquid up the tube, which is 0.3 mL, or 300 mcg spent before delivery begins. Assume 0.25 mL sitting below the reach of the dip tube at the end, another 250 mcg. Usable volume is 3 minus 0.3 minus 0.25, which is 2.45 mL. At 0.1 mL per stroke that is 24 whole actuations, and a partial 25th that will not fire cleanly.

The bottle therefore delivers about 2.4 mg of a 3 mg label. Neither subtraction is printed anywhere, and both are assumed inputs here rather than measurements.

A vial loses almost nothing to the container. A 10 mg vial reconstituted with 2 mL gives 10 divided by 2, which is 5 mg per mL, and close to the full 2 mL is retrievable with a syringe.

At 0.1 mL per session, which is 10 units on a U-100 barrel and 500 mcg of material, that vial holds 2 divided by 0.1, which is 20 withdrawals. At 0.05 mL, or 250 mcg, it holds 40. At 0.2 mL, or 1 mg, it holds 10.

The same 10 mg reconstituted with 5 mL gives 2 mg per mL and yields 50 withdrawals of 0.1 mL, but each of those now carries 200 mcg rather than 500. More withdrawals, identical total mass. Adding water never adds material, and any schedule that appears to gain days from a larger fill volume has quietly reduced the mass per session.

The bottom two rows are the ones to look at twice, because they are the rows where the container outlasts something else.

Reconstituted liquid does not keep indefinitely, and the limit is a property of the preparation rather than of any schedule written on top of it. No stability figure for this compound is asserted here. Work it instead with an assumed laboratory policy of 28 days for any reconstituted vial held refrigerated, since the assumption is the point.

Under that policy, the 40 withdrawal row fails. Forty daily sessions need 40 days, which is 12 days past the limit. Twelve withdrawals at 0.05 mL is 0.6 mL, and at 5 mg per mL that is 3 mg of a 10 mg label discarded. The 50 withdrawal row is worse: 22 days past the limit, 2.2 mL and 4.4 mg written off.

The 20 withdrawal row fits comfortably. So the fill volume that looked wasteful, because it produced fewer withdrawals, is the one that gets the most material out of the vial once the clock is applied. That inversion is the single most useful thing container arithmetic contributes to planning, and it is invisible if only mass per session is considered.

A filled spray bottle sits under whatever expiry its manufacturer states, which is a different kind of limit and one the buyer did not set.

No prices are quoted here. Ratios are enough, and they behave better than invented figures.

Let a 10 mg vial cost P. Assume a 30 mg vial is priced at 2.5 times that, so 2.5P. Per labelled mg, the small vial is P divided by 10, or 0.1P. The large one is 2.5P divided by 30, which is about 0.083P, so it looks cheaper by a sixth.

Now apply the clock. Reconstitute the 30 mg vial with 3 mL to reach 10 mg per mL, and run it at 0.05 mL a day, which is 500 mcg. Under a 28 day policy, 1.4 mL is used and 14 mg leaves the vial. Cost per used mg is 2.5P divided by 14, which is about 0.179P. The 10 mg vial at 5 mg per mL and 0.1 mL a day empties in 20 days with nothing discarded, so its cost per used mg stays at 0.1P.

Per label, the large vial wins. Per milligram that actually gets used, it costs roughly 1.8 times as much. The spray has a milder version of the same gap: a 3 mg label that delivers 2.4 mg means cost per delivered mg is the bottle price divided by 2.4, which is 1.25 times the figure a buyer would get by dividing by 3.

Nothing above says how long a course should be, and no source available to this page says it either.

Semax has no registered interventional trials, so no trial identifier is cited. It does have a real Russian regulatory history and genuine medical use, which is evidence rather than folklore. It is also evidence a Western reader cannot inspect the way a submitted registration file can be inspected, and it describes a manufactured medicine used under supervision rather than a research chemical prepared by hand. The problem is transferability, not absence, and no amount of division crosses that gap.

Animal work in rats and mice exists and reports exposure windows in animals given amounts per kilogram of body weight. Those windows are not human durations and are not converted here.

So the cycle length this page can defend is a container life. Twenty four strokes, or 20 withdrawals, or 28 days of water, are all real limits. A number of weeks for a person is not something the arithmetic can reach, and presenting one as though it followed from the maths would be a fabrication with a table behind it.