Semax / Selank: focus and calm, paired.

What is the Semax / Selank stack?

Semax and Selank are short synthetic peptides originally developed in Russia for cognitive and anxiolytic use. Semax is a fragment of ACTH modified for stability, studied for attention, mental stamina, and neuroprotection. Selank is derived from tuftsin, a naturally occurring immune-modulating peptide, and is studied for anxiety reduction and stress resilience without sedation.

Stacked, they cover two halves of the same problem. Semax addresses the depleted, foggy, hard-to-focus state. Selank addresses the wired, anxious, over-activated state. Together they are used by clients whose cognitive complaint is a mix of both — the familiar pattern of being simultaneously exhausted and unable to settle.

How Semax and Selank work

Semax appears to increase BDNF (brain-derived neurotrophic factor) and modulate dopamine and serotonin signaling. BDNF supports the maintenance and plasticity of neurons, which is the mechanistic basis for the reported effects on attention, learning, and recovery from cognitive fatigue.

Selank appears to influence GABAergic signaling and the expression of enkephalins — the body's own calming peptides — without acting as a sedative or producing dependence the way benzodiazepines can. Clients typically describe the effect as a lower baseline of reactivity rather than being medicated.

Researched benefits

Most published research on Semax and Selank comes from Russian clinical and preclinical literature; Western trial data is limited. We describe this stack as promising and closely supervised, not proven or guaranteed.

How the Semax/Selank stack is dosed

There is no single correct dose. Semax and Selank are typically used in short cycles rather than continuously, with dose and frequency matched to the demand you are managing and your response over the first two weeks.

At Origin Wellness, both peptides are prescribed as subcutaneous injections. They may be given together or on separate schedules depending on whether focus or anxiety is the primary complaint.

• Injectable (subcutaneous)

  Injected into fatty tissue, typically the abdomen, on a daily or near-daily schedule during a cycle of two to four weeks. Your clinician sets the dose, ratio between the two peptides, and cycle length, then adjusts at follow-up.

At Origin Wellness, dosing is never self-directed. Your protocol is written by a licensed physician after reviewing your assessment, and it is adjusted at follow-up based on your response. Read more about how that review works on our approach page.

Safety, side effects, and who should avoid it

Reported side effects are generally mild: injection-site irritation, transient headache, or mild changes in sleep or mood in the first days of a cycle. The larger caution is the limited long-term human data outside Russian literature, which is why these peptides belong in a supervised protocol with follow-up.

Because both peptides affect neurotransmitter signaling, interactions with psychiatric medications must be reviewed before starting.

• • Not appropriate during pregnancy or breastfeeding.
• • Requires clinician review if you take antidepressants, anxiolytics, stimulants, or other psychiatric medications.
• • Not a substitute for treatment of a diagnosed psychiatric condition.
• • Should be disclosed to any other treating physician alongside your current medications.

How the Semax/Selank stack fits into a full protocol

Cognitive peptides are most useful when the foundations are already addressed. Sleep debt, unmanaged blood sugar, and chronic under-recovery will out-argue any nootropic. We look at those first, then use Semax and Selank to raise the ceiling rather than patch the floor.

This stack is often run alongside a metabolic or recovery protocol and a coaching program — Origin Balance for women or Origin Peak for men — so that focus gains are supported by training, nutrition, and sleep structure.

Frequently asked questions