Semax vs Selank
There is no winner on this page. What is set side by side is the published record behind each one, which is the part the two are rarely compared on.
Both in Cognitive and neuro
They are usually bought together and the pairing has never been studied. Search both names and eleven articles come back, and in none of them did researchers give both peptides to the same subjects. The one study containing both names does the opposite of what a stack implies: 52 healthy people scanned in three separate arms, one given Semax, one given Selank, one given nothing. They share the last three of their seven building blocks, which is a plausible route to a shared mechanism, and a reason two compounds acting alike may not add up rather than an argument for combining them. Selank also has no dose to compare against, because none of its three trials reports one.
| Field | Semax | Selank |
|---|---|---|
| What a trial gave | 800 to 8,000 mcg, up the noseThe Russian 0.1 percent label | No trial has ever reported a doseThree Russian trials, 192 patients, no dose in any of them |
| What circulates | 500 to 3,000 mcg, usually injected | 900 mcg a day from the drops, 1,350 quoted by vendors |
| The gap | Below the studied dose | No studied dose to compare |
| How long it lasts | I could not find a measurement of this in a person, by any route, nose or needle. | No half life has been published in a person. The only figure of that kind anywhere in the record is on the Russian label, which describes the substance clearing the blood within about five minutes. |
| Route studied | Up the nose, as drops | Up the nose, as drops. Every documented human use is by that route. |
| Route used | Injected under the skin, at home | Injected. The injectable solution that is actually sold has never been compared with the nose drops in a clinical study. |
| Vial sizes | 30 mg | 5, 10, 20 mg |
The distance, stated
Below the studied dose
Semax
Below the label range and by a different route. Almost everything sold here is injected; every published study went intranasally.
No studied dose to compare
Selank
There is nothing to compare against. None of the three trials reports a dose or a treatment length, so both circulating numbers came from somewhere other than a study: 900 mcg per day is a derivation from assuming 20 drops to a millilitre of the Russian nasal drops, and the 1,350 mcg per day that vendors attribute to the 2008 trial is absent from every primary source.
What people get wrong
Semax
The expensive mistake is treating N Acetyl Semax and N Acetyl Semax Amidate as upgraded, stronger versions of the original. Nothing at all has been published on them, and the one study that looked at adding that acetyl group found it wiped out a protective effect the plain version had on cells, which is the opposite of what the marketing claims.
Selank
The costly mistake is the Semax pairing, because it is not a stack anybody has studied. Search for both names and you get 11 articles, and in none of them did researchers give both peptides to the same subjects. The one study that contains both names does the opposite of what a stack implies: Panikratova 2020 scanned 52 healthy people in three separate arms, one given Semax, one given Selank and one given nothing. The two are chemically related, sharing the last three of their seven building blocks, and that shared tail is a plausible route to a shared mechanism, which is a reason two compounds that act alike may not add up to more when taken together rather than an argument for combining them. I could find nobody who has checked.
Every figure above is carried across from each compound’s entry, which is where the citations live.
All 65 compounds on one page at what circulates vs what was studied, or pick another two to compare.