[Go to the reading](#ntp-main) [Neurotech](/)Menu [The signals](/neuropeptides/)[The blend](/semax-selank/)[DSIP](/dsip/)[Evidence](/evidence/)[Compare](/compare/) [Neurotech](/) /Compare # Three histories, different missing pieces This comparison puts the three molecules beside one another without turning them into a ranking. Their origins, experimental settings and unanswered questions are more useful than a claim that one is strongest. [Explore the Semax and Selank blend at Promise Peptides](https://mypromise.com/products/semax-selank?utm_source=neurotech&utm_medium=affiliate&utm_campaign=comparison&utm_content=compare-opening) Neurotech Peptides may earn money when readers become Promise patients. On this frequency - [Compare the three](/compare/) - [Research context](/evidence/) In this reading - [The molecules at a glance](#ntp-section-1) - [Compare origins without inferring outcomes](#ntp-section-2) - [Compare measurements before comparing reputations](#ntp-section-3) - [Human comparisons have narrow boundaries](#ntp-section-4) - [Safety is not a leaderboard](#ntp-section-5) - [Compare the actual care routes](#ntp-section-6) ## The molecules at a glance Three molecules: origin, research setting and the gap | Molecule | Starting point | Research setting | Still missing | | --- | --- | --- | --- | | Semax | Part of a stress-response hormone, with extra building blocks added to slow breakdown | Rat nerve-cell support proteins; small human illness and imaging studies | Everyday cognitive outcomes and long-term safety | | Selank | Tuftsin, a short immune-system peptide, with extra building blocks added | Rat gene studies of GABA, a signal that reduces nerve-cell firing; small Russian anxiety comparisons | Independent clinical confirmation and long-term interactions | | DSIP | Nine-part peptide characterized in rabbit experiments | Sleep-related recordings and unresolved receptor biology | A confirmed specific receptor and strong modern clinical evidence | These three molecules correspond to two products in the care route described here. Promise Peptides offers Semax and Selank together as one blend, alongside a distinct DSIP product. The [blend explanation](/semax-selank/) addresses why evidence on an ingredient cannot establish the effects of that combination. ## Compare origins without inferring outcomes Semax extends a fragment of ACTH, a hormone involved in the stress response. Selank extends tuftsin, an immune-related fragment released from an antibody. Both are synthetic chains of seven amino acids. Similar length and a shared extension do not establish the same biological effects. DSIP is a nine-amino-acid peptide first characterized through rabbit sleep experiments. It has been reported in biological samples, yet the way it is produced and the identity of a specific receptor remain unresolved. “Natural” and “synthetic” describe different facts about origin; neither word supplies a safety conclusion. ## Compare measurements before comparing reputations For Semax, [rat BDNF research](https://pubmed.ncbi.nlm.nih.gov/16635254/) concerns a protein involved in nerve-cell survival and connections. For Selank, [rat gene research](https://pubmed.ncbi.nlm.nih.gov/26924987/) concerns GABA signaling, which generally dampens nerve-cell firing. These experiments measure different things in animals. Neither establishes how a healthy reader performs at work. DSIP’s [critical review](https://pubmed.ncbi.nlm.nih.gov/16539679/) highlights a more basic uncertainty: its proposed sleep role is not well established and its specific receptor remains unidentified. That makes a confident account of exactly what it does in people especially difficult. A longer history does not automatically provide a firmer mechanism. ## Human comparisons have narrow boundaries There is no large human trial establishing which of these compounds is best for a healthy person’s focus, memory or calm. Small Russian Semax studies concern neurological illness or brain activity. Selank’s [62-patient anxiety comparison](https://pubmed.ncbi.nlm.nih.gov/18454096/) lacked a placebo group and does not state randomization or blinding in its abstract. [A double-blind DSIP study](https://pubmed.ncbi.nlm.nih.gov/1299794/) in people with chronic insomnia reported modest effects of limited clinical importance. Its participants and research questions differed from those in the anxiety studies. ## Safety is not a leaderboard None of the three has the large, long-term human safety record needed for confident estimates across many health situations. Inadequate adverse-effect reporting can hide uncertainty. Other medicines and existing conditions can matter even when a proposed mechanism sounds gentle. ### Anecdotal, not clinical evidence People online may favor one name for clarity, another for calm and another for sleep. Reports also include discomfort and no apparent change. Such preferences cannot separate expectation, product differences or concurrent substances, and they do not rank clinical effectiveness. ## Compare the actual care routes Each request through Promise Peptides reaches a licensed U.S. provider for an individual decision. The assessment can find that a person is not eligible. The route serves U.S. patients, and availability varies with state and treatment. When prescribed, the blend or DSIP is prepared by a licensed U.S. compounding pharmacy. The medicines described here are compounded and are not FDA-approved. A live product page establishes an access route, rather than a comparative clinical advantage. Our [process guide](/how-it-works/) explains the next step and why a provider may decide against prescribing. ## Compare evidence before considering access Promise Peptides offers review for the combined Semax and Selank product and for DSIP. Which, if either, is appropriate depends on a licensed U.S. provider’s assessment. [Explore DSIP’s provider route at Promise Peptides](https://mypromise.com/products/dsip?utm_source=neurotech&utm_medium=affiliate&utm_campaign=comparison&utm_content=compare-closing) Neurotech Peptides Neurotech is a reading guide, with no clinic, pharmacy or storefront behind its name. [Questions](/faq/)[About Neurotech](/about/)[Contact](/contact/)[References](/references/) © 2026 Neurotech Peptides Neurotech Peptides may earn money when readers become Promise patients. Neurotech Peptides is an independent guide and is not Promise Peptides. [Explore Promise Peptides](https://mypromise.com/?utm_source=neurotech&utm_medium=affiliate&utm_campaign=comparison&utm_content=compare-footer) Medical decisions need a licensed provider’s assessment; an article cannot assess your health.