Skip to content

Semax vs TB-500: side-by-side comparison

Peptide

ACTH(4-7)-PGP · N-Acetyl Semax · NASA (N-Acetyl Semax Amidate)

A synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from ACTH(4-10) with a Pro-Gly-Pro tail for stability. Primary nootropic with cognitive enhancement, focus, and neuroprotection. Significantly upregulates BDNF (1.4x protein, up to 3x mRNA per Dolotov et al. 2006) and modulates NGF expression. Unlike full ACTH, it lacks steroidogenic (adrenal) and melanocyte-stimulating activity, so it does not produce cortisol/HPA stimulation or tanning; some more recent reviews suggest it may still interact with central MC4/MC5 melanocortin receptors, so "no melanocortin activity at all" overstates current evidence. Available as standard Semax, N-Acetyl Semax, and NASA (Amidate) - each progressively more stable.

1.0/10 natty
Full breakdown →
VS
Peptide

Thymosin Beta-4 · TB4 · TB 500

Focuses on systemic healing, cell migration, and flexibility. A naturally occurring peptide present in almost all human cells that plays a key role in tissue repair and regeneration.

1.0/10 natty
Full breakdown →

1 / 10 natty scale / 1

Same lane

Both sit in the same class and are run for health. This is a like-for-like comparison: read the gaps as real trade-offs.

The tape

Core ratings

The same three rulers every entry on the site is scored with, read head to head.

SemaxTB-500
1.0

Natty scale

1 natural · 10 heavy

1.0
3.5

Effectiveness

Documented effect · of 5Δ1

4.5
1.5

Side-effect severity

Documented burden · of 5Δ0.5

1.0

Cost side

Body-load fingerprint

Where each one actually lands its strain, on the calculator's thirteen channels. Tap a row for what it means and which labs track it.

SemaxTB-500

Systemic

Injection & site care

Bars show strain at each one's typical protocol, not your dose. ≈ marks values inferred from side-effect data or category rather than hand-graded. For your numbers, run the calculator.

Logistics

The vitals

SemaxTB-500
Peptide
Classmatch
Peptide
Nasal Spray
Route
Subcutaneous
200-900 mcg/dayIntranasal 1-3x daily divided doses. Morning/early afternoon to avoid sleep disruption.
Typical dose
2-6 mg/week2x/week during a 4-6 week loading phase, then often reduced to 1x/week for maintenance
~2-8 minutes
Half-life
~2-3 hours
2-4 weeks
Typical run
6-12 weeks
Research chemical
Legal statusmatch
Research chemical
UnclearS2. Peptide Hormones, Growth Factors, Related Substances and Mimetics (potential overlap with S2.4 Corticotrophins)
WADA
ProhibitedS2. Peptide Hormones, Growth Factors, Related Substances and Mimetics

Benefit side

What each is for

Shared goals carry both dots; a goal with one dot belongs to that side alone.

SemaxTB-500
HealthRecovery

Run for

Cognitive EnhancementImproves spatial and working memory, learning acquisition/retention, sustained attention, mental clarity. BDNF-mediated neuroplasticity effects.
NeuroprotectionDecreases cortical infarction volume and improves post-ischemic learning/memory retention in rodent stroke models (Romanova et al. 2006); protects against glutamate excitotoxicity. Underlies its Russian clinical approval for stroke and cognitive disorders.
Focus and Mental EnergyMild stimulant profile via dopamine modulation. Enhanced motivation and drive. Does not cause jitteriness like traditional stimulants.
Training SupportMaintains mental clarity during caloric deficit. May enhance mind-muscle connection (anecdotal). Supports motor learning and skill acquisition.

Documented upside

  • Upregulates BDNF (1.4x protein, up to 3x mRNA) and modulates NGF expression
  • Improved memory, learning, and attention
  • Neuroprotective effects demonstrated in stroke models
  • Lacks the steroidogenic/melanocyte-stimulating activity of full ACTH (no tanning, no cortisol/HPA stimulation)
  • Russian clinical approval with human study data
+3 more on the full page

Run for

Systemic HealingPromotes healing throughout the body, not just at injection site.
FlexibilityImproves tissue flexibility and reduces adhesions.
Inflammation ReductionPowerful anti-inflammatory effects.

Documented upside

  • Systemic healing effects
  • Reduced inflammation
  • Improved flexibility
  • Enhanced wound healing
  • Promotes new blood vessel formation
+1 more on the full page

The downsides

Side effects, aligned

Each entry's documented side effects, sorted onto the same body systems so the gaps and the overlaps are visible. Tap any effect for the detail.

SemaxTB-500
Mood, sleep & CNS

None documented

Other documented effects

The exit

Hormonal fallout & recovery

What each does to your own hormone axis while on, and what leaving it costs.

SemaxTB-500
Not required
PCT
Not required
While-on only
What sticks
While-on only

Semax

Does not affect HPT axis. No HPA axis suppression documented. No PCT required. No interference with hormone panels.

TB-500

Does not affect hormones. No PCT required.

Read-out

How they separate

  1. 01

    Enhancement

    They land at almost the same point on the natty scale (1/10 vs 1/10): a similar distance beyond natural.

  2. 02

    Side-effect bill

    Semax's documented side-effect severity is heavier (1.5/5 vs 1/5). The body-load fingerprint above shows where that weight actually lands.

  3. 03

    Body load

    The widest gap at typical protocols is mood & sleep (Semax 2.2/10 vs 0/10).

  4. 04

    Coming off

    Neither requires PCT: both leave the natural testosterone axis running.

  5. 05

    Logistics

    Semax runs as nasal spray, TB-500 as subcutaneous; typical runs are 2-4 weeks vs 6-12 weeks.

Generated from each entry's data file. Descriptive, not a recommendation; nothing here is medical advice.

Full breakdownSemax→Full breakdownTB-500→

More matchups

BPC-157 vs TB-500Noopept vs SemaxSemax vs BPC-157Semax vs GHK-CuTB-500 vs GHK-Cu