SYNAPSE Blend (Semax / Selank / MOTS-c / Tesamorelin): What It Is, Where to Get It Prescribed, and What It Costs

SYNAPSE is not a single molecule. It is four independently studied peptides — Semax, Selank, MOTS-c and tesamorelin — dissolved together in one sterile multi-dose vial by a compounding pharmacy. Each has its own research literature, its own described mechanism and its own regulatory file at the FDA. The name is a brand name for the combination; it does not appear in any journal. That shapes everything on this page: "does SYNAPSE work" has to be broken into four questions, because the combination has never been studied as a combination.

The rationale prescribers give is a brain-and-body split. Semax and Selank come from the same Russian research programme and are described as acting on the brain's own signalling — one on attention-related growth-factor pathways, the other on the GABA system that governs the stress response. MOTS-c and tesamorelin are described as acting on metabolism — one at the cell's fuel sensing, the other through the pituitary's own growth hormone pulse. The argument for combining them is that someone who wants to think clearly and have the physical energy to act on it has two problems, not one.

The proportions are worth noticing. Tesamorelin and MOTS-c are 20 of the 30 mg in the vial, so by mass SYNAPSE is two-thirds a metabolic preparation with two smaller neuropeptide components. The ratio is fixed by the pharmacy's formulation and cannot be adjusted per component, which is the genuine trade-off of any blend.

It is not a stimulant. It is not a substitute for prescribed ADHD, anxiety or depression treatment, and it is not a treatment for stroke, dementia or mild cognitive impairment — nothing on this page is a reason to delay care for any of those. It is not growth hormone: tesamorelin delivers the instruction to the pituitary, which decides how much to release. And it is not a weight-loss product; tesamorelin's approved label states it is not indicated for weight-loss management, and MOTS-c has no human trials at all.

Semax is a heptapeptide, Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues are positions 4 to 7 of adrenocorticotropic hormone, a region studied for decades for its effects on attention and learning in animals; the Pro-Gly-Pro tail was added to slow breakdown. The literature describes it as devoid of corticotropic activity — it is not expected to raise cortisol.

The most cited mechanism is a 2006 paper in Brain Research reporting that Semax increased BDNF protein and TrkB receptor phosphorylation in the rat hippocampus, alongside more conditioned avoidance responses in treated animals. BDNF is the growth factor most closely tied to synaptic plasticity, so this is the finding the "cognitive" label rests on. Later rat work describes Semax raising neurotrophin transcription selectively in ischaemic brain tissue. A fuller treatment is on the Semax page.

Selank is also a heptapeptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro. The first four residues are tuftsin, a naturally occurring immune-signalling fragment of immunoglobulin G, with the same stabilising tail added by the same designers.

The mechanism most often cited is at the GABA-A receptor. Cell-membrane work describes Selank altering how GABA itself binds, in the manner of a positive allosteric modulator, rather than acting on the receptor directly, and a 2016 study in Frontiers in Pharmacology reported that Selank changed 45 of 84 neurotransmission genes measured in rat frontal cortex, in a pattern that correlated with what GABA itself produced. An older line of work describes Selank inhibiting the enzymes that break down enkephalins in human plasma. The picture is a peptide that modifies the brain's own inhibitory signalling rather than driving it — the basis for the Russian literature's description of anxiolytic activity without the sedation associated with benzodiazepines. The Selank page goes further.

MOTS-c is a 16-amino-acid peptide encoded in a short open reading frame inside the mitochondrial gene for 12S ribosomal RNA, identified in a 2015 paper in Cell Metabolism. It belongs to a small family of mitochondrial-derived peptides that changed the picture of mitochondria from energy factories to organelles that send their own signals back to the cell.

The central mechanism described is metabolic rather than receptor-based. In cultured cells the 2015 paper reported MOTS-c inhibiting the folate cycle, causing a metabolite called AICAR to accumulate; AICAR activates AMPK, the enzyme cells use as a low-fuel sensor and the same one exercise switches on. Skeletal muscle appeared to be the primary target. A 2021 paper in Nature Communications reported that a bout of exercise raised the body's own MOTS-c in muscle and blood in healthy young men — the one human finding, and an observational one: what the body does after exercise, not what happens when the peptide is injected. See the MOTS-c page.

Tesamorelin is the full 44-amino-acid sequence of growth-hormone-releasing hormone with a trans-3-hexenoic acid cap that protects it from the enzyme DPP-4, so it survives a subcutaneous injection long enough to reach the pituitary. It binds the GHRH receptor and prompts a pulse of the body's own growth hormone; because the pituitary is doing the releasing, the feedback loops involving somatostatin and IGF-1 still apply, and IGF-1 is the marker a physician tracks.

Unlike the other three components, each step has been measured in humans. In the 2007 New England Journal of Medicine trial IGF-1 rose by 81% over 26 weeks; in the 2012 Archives of Neurology trial in older adults it rose by 117% and stayed within the physiological range. Growth hormone is lipolytic and visceral fat is particularly responsive to it, which is why every tesamorelin trial has reported a reduction in visceral fat with no significant change in subcutaneous fat. The tesamorelin page covers the approved product in full.

The map below is the clinical rationale for the blend. It is a rationale, not a finding — no study has confirmed that the four act in concert when injected together.

Semax's animal literature is coherent: more BDNF and TrkB signalling in the hippocampus, better performance on avoidance-learning tasks, neurotrophin changes in the ischaemic cortex. Its human literature is Russian and clinical: trials published in the Korsakov Journal of Neurology and Psychiatry between 1997 and 2018 describe intranasal Semax in patients with acute ischaemic stroke and chronic cerebrovascular disease, reporting faster recovery of neurological scores. Those are real human studies, but they are in stroke patients, by the intranasal route, run by the groups that developed the molecule. There is no randomised trial of Semax for attention or focus in healthy adults.

Selank has more human data than most compounded peptides, all of it from Russia. A 2008 paper in the Korsakov Journal reported Selank in patients with generalised anxiety disorder and neurasthenia, with anxiety-score improvement and a change in a blood enkephalin marker that tracked the clinical effect. A 2014 paper in the same journal compared Selank with phenazepam, a benzodiazepine, and reported comparable anxiolytic effect with fewer sedation-type complaints. These were intranasal, comparator-controlled designs in diagnosed patients, not placebo-controlled trials in healthy people.

MOTS-c's evidence is mouse and cell work. The 2015 Cell Metabolism paper reported less diet-induced weight gain and better insulin sensitivity in treated mice; the 2021 Nature Communications paper reported better physical performance across ages in mice. In humans the data is observational only. Nobody has given MOTS-c to people in a controlled trial and measured what happened.

Tesamorelin is the component with the strongest human evidence. Two phase 3 randomised, placebo-controlled trials in over 800 adults with HIV-associated abdominal fat accumulation, pooled in a 2010 paper in the Journal of Clinical Endocrinology and Metabolism, reported a roughly 15% reduction in visceral adipose tissue on CT over 26 weeks at 2 mg daily, with no significant change in subcutaneous fat. That is what the FDA approval rests on.

The cognition trial deserves an accurate description, because it is the reason tesamorelin is in a blend with this name. The 2012 Archives of Neurology trial randomised 152 adults aged 55 to 87 — 66 with mild cognitive impairment, the rest cognitively healthy — to tesamorelin 1 mg or placebo, self-injected 30 minutes before bedtime for 20 weeks. The intent-to-treat analysis reported a favourable effect on a cognitive composite, comparable in the MCI and healthy groups and driven mainly by executive function, with a trend in verbal memory that did not reach significance. IGF-1 rose 117% and stayed within the physiological range; body fat fell 7.4%. Adverse events were mild but more frequent on the drug, 68% versus 36%. A 2013 substudy in JAMA Neurology reported higher brain GABA levels on spectroscopy in 30 of those participants, without a demonstrated link to the cognitive changes. The authors concluded that longer trials were needed. It is a single 20-week trial of tesamorelin alone, in older adults, at 1 mg every day — an interesting signal, not an established use, and not evidence about this blend.

This is the honest part, and the part worth understanding before starting.

There are no randomised controlled trials of SYNAPSE, or of any four-peptide combination of these components, in humans. The blend has never been studied as a blend. Evidence is per component, and it is uneven:

• Tesamorelin has randomised, placebo-controlled trials: the phase 3 visceral-fat trials behind the approved product, and one 20-week cognition trial in older adults, all at 1–2 mg daily of the approved product.
• Selank has Russian clinical trials in diagnosed anxiety disorders, intranasal and comparator-controlled. None outside Russia, none placebo-controlled, none of the injectable form.
• Semax has Russian clinical trials in ischaemic stroke, intranasal. No randomised trials for attention or cognition in healthy adults.
• MOTS-c has no human trials of any kind.

Much of medicine rests on mechanism plus clinical experience, and that is the basis physicians prescribe SYNAPSE on. But the accurate framing is "one component with human trials for other indications, two with foreign clinical data in patient populations, one with animal data only," not "proven in people."

• That four peptides together do more than any one alone. No study has compared the blend with its components.
• Any cognitive outcome for the blend. The one cognition trial is of tesamorelin alone, at 1 mg daily for 20 weeks, in adults aged 55 to 87; it does not transfer to a 0.5 mg weekday dose inside a four-peptide vial, or to younger adults.
• An effect size for any indication, because those trials have not been run.
• A timeline in humans. Timelines given by prescribers are clinical experience, not trial endpoints.
• Long-term safety over years of continuous use. Tesamorelin's own label states that long-term cardiovascular safety has not been established and that the effects of prolonged IGF-1 elevation are unknown.
• Efficacy for any condition as an FDA-approved treatment. SYNAPSE is not approved for anything; the approved tesamorelin product is approved for one indication that is not the reason anyone takes this blend.

Semax was placed in Category 2 of the FDA's 503A bulk drug substances list in 2023, the category for nominated substances with identified safety concerns; the concern recorded was potential immunogenicity for certain routes. It is no longer in Category 2. The FDA's safety-risks page, current as of 22 April 2026, lists "Semax (heptapeptide)" among bulk drug substances nominated but withdrawn, and the 503A categories document updated 14 May 2026 does not carry it in Category 1, 2 or 3.

On 24 July 2026 the FDA's Pharmacy Compounding Advisory Committee considered Semax (free base and acetate) for the 503A Bulks List, for the nominated uses of cerebral ischaemia, migraine and trigeminal neuralgia. FDA scientists recommended against inclusion, citing insufficient safety, efficacy and characterisation information; the committee voted 8–5, with one abstention, to recommend adding it.

Selank acetate, listed by the FDA as "Selank acetate (TP-7)," was placed in Category 2 in 2023 with the same concern. Its nomination was later withdrawn; the FDA's safety-risks page now lists it among substances nominated but withdrawn, and it does not appear in Category 1, 2 or 3 of the 14 May 2026 document. It was not on the agenda of the July 2026 advisory committee meeting, and it is not among the five substances the committee is scheduled to consider before the end of February 2027. So: not flagged as a safety risk, never evaluated by the committee, no active nomination.

MOTS-c was placed in Category 2 in 2023; the FDA's recorded concern was immunogenicity risk with no human exposure data. On 15 April 2026 the FDA removed MOTS-c from Category 2, one of twelve peptides removed after their original nominations were withdrawn; it now sits in the nominated-but-withdrawn list and in no active category.

On 23 July 2026 the advisory committee reviewed MOTS-c (free base and acetate) for the nominated uses of obesity and osteoporosis and voted 7–5, with two abstentions, to recommend adding it to the 503A Bulks List — the narrowest margin of the six peptides it recommended that week, and again against the recommendation of FDA's own reviewers.

Tesamorelin's position is different and did not move in 2026. An FDA-approved tesamorelin product exists. Egrifta (tesamorelin acetate), BLA 022505, was approved on 10 November 2010 for the reduction of excess abdominal fat in HIV-infected adult patients with lipodystrophy. The current formulation, Egrifta WR, carries a label revised March 2025 with the same single indication, dosed at 1.28 mg once daily, and three limitations of use: long-term cardiovascular safety has not been established, it is not indicated for weight-loss management because its effect on weight is neutral, and there is no evidence it improves antiretroviral adherence. Because it is the active ingredient of an approved product it was never nominated for the 503A bulks list, does not appear in the 14 May 2026 categories document, and was not on the July 2026 agenda.

Compounded tesamorelin is not Egrifta. The tesamorelin in SYNAPSE is prepared by a state-licensed pharmacy to a physician's prescription, has not been reviewed by the FDA as a finished product, and is prescribed off-label — a physician's decision and common across medicine, but it should be understood as such.

None of the four components is restricted. Semax and MOTS-c were recommended for the positive 503A list by the advisory committee in July 2026 and await the FDA's own determination, which is still pending as of September 2026. Selank has no active nomination. Tesamorelin is the active ingredient of an approved biologic and sits outside the bulks-list process entirely. SYNAPSE itself is not an FDA-approved drug product, and compounded medications never are. See are peptides FDA approved.

Most people notice little beyond injection-site tenderness. Where anything else is described early, it tends to be the Selank side — a lower background stress level — rather than focus or energy. Noticing nothing in this window is normal and is not a sign the course is not working.

The window one vial covers on a weekday schedule. Prescribers most often describe subjective changes here: attention feeling steadier through the working day, or deeper sleep, which is consistent with tesamorelin being described as amplifying the growth hormone pulse of slow-wave sleep. These are reports, not measurements.

Where physical change is described, it is described here, and it typically takes a second and third vial to reach. Tesamorelin's own trials measured visceral fat at 26 weeks; nothing about body composition is expected inside a month. This is also when a physician will usually want a repeat IGF-1 and glucose, the two numbers the approved tesamorelin product's label says to watch.

There is no withdrawal and no rebound described for any component. Tesamorelin's effect on the growth hormone pulse stops when dosing stops, and the phase 3 trials reported visceral fat returning toward baseline after discontinuation. Whether anything on the neuropeptide side persists is not something the research answers.

The directions are written in millilitres and in insulin-syringe units because that is what you can actually read off the barrel. 0.25 mL is 25 units on a U-100 syringe. You are not calculating anything — the number is printed on your medication. Because the four are in fixed proportion, every dose delivers the same split: 0.25 mg Semax, 0.25 mg Selank, 0.5 mg MOTS-c and 0.5 mg tesamorelin; you cannot take more of one and less of another. If your directions and syringe markings appear to disagree, ask before dosing.

Subcutaneous means into the fat layer, not the muscle. The abdomen is the usual site, rotated so the same spot is not used repeatedly. Some prescribers direct the dose in the evening, because tesamorelin is described as amplifying the growth hormone pulse of early sleep and the 2012 cognition trial dosed at bedtime; others direct morning dosing because of the Semax and Selank components. Follow what is printed on your vial.

20 doses at five per week is four weeks of weekday dosing, which is why refills run on a monthly cycle. Weekends off is part of the schedule, not a missed dose. One vial per fill, always — not a stockpile.

Refrigerated, and it ships that way in insulated packaging with ice packs. Beyond-use dating runs from first puncture and is on the label; a multi-peptide vial is not something to keep past it.

The two-peptide preparation is the brain-only version. It omits tesamorelin — the component with human trial evidence, but also the one that raises IGF-1 and brings glucose and fluid-retention considerations — and MOTS-c. For someone whose goal is focus and stress alone, it is the more targeted prescription and a physician may reasonably prefer it.

The ELEVATE blend keeps Semax and Selank and swaps the metabolic pair for BPC-157 and KPV, so it is the choice when the second problem is gut, tissue or inflammation rather than energy. The SERENITY blend shares only Selank, pairing it with DSIP and the CJC-1295 / ipamorelin secretagogues, aimed at sleep and calm rather than attention. If the complaint is "wired and tired," SERENITY is the usual conversation; if it is "flat and unfocused," SYNAPSE.

The FUSION blend and the PHYSIQ blend both carry tesamorelin and MOTS-c without Semax or Selank — the body-only versions of the same metabolic pair. SYNAPSE is supplied as a vial only; there is no Pen cartridge for this blend.