TB-500 + Ipamorelin Stack: Complete Protocol, Dosing, and Evidence Review

What Are TB-500 and Ipamorelin, and Why Are They Stacked?

TB-500 is a 43-amino-acid synthetic analogue of the actin-sequestering region of thymosin beta-4 (TB4). Ipamorelin is a pentapeptide that selectively binds the ghrelin receptor (GHS-R1a) to stimulate pulsatile growth hormone release. Practitioners combine them because they act on distinct biological pathways that converge on tissue repair, with TB-500 targeting cellular migration and Ipamorelin amplifying the anabolic GH-IGF-1 axis.

Thymosin Beta-4 and Its Active Fragment

Thymosin beta-4 is an endogenous 43-amino-acid peptide found at high concentrations in platelets and wound fluid. Its primary biological role is sequestering G-actin monomers to control cytoskeletal dynamics, which directly affects cell migration, angiogenesis, and inflammatory modulation. Researchers identified the tetrapeptide Ac-SDKP as one bioactive region responsible for many of TB4's anti-fibrotic and pro-angiogenic effects.

The synthetic fragment marketed as TB-500 corresponds to amino acids 17 to 23 of the full TB4 sequence. In a murine cardiac injury model, thymosin beta-4 promoted cardiomyocyte survival and reduced infarct size, findings that have driven interest in its tissue-repair applications despite the absence of human trials in most indications.

Ipamorelin as a Fifth-Generation GHRP

Growth hormone-releasing peptides (GHRPs) have progressed through several generations. Ipamorelin, developed in the late 1990s, stands out because it produces a clean GH pulse with minimal cortisol or prolactin co-secretion compared to earlier compounds like GHRP-2 or GHRP-6. A pharmacological characterization published in the European Journal of Endocrinology confirmed that Ipamorelin stimulated GH release in rats with a selectivity profile superior to GHRP-6, including negligible ACTH stimulation at therapeutic doses.

Pulsatile GH release triggers hepatic IGF-1 production, which drives protein synthesis, satellite cell activation, and collagen deposition, all processes relevant to musculoskeletal recovery.

The Mechanistic Rationale for Combining Them

TB-500 acts primarily at the level of actin dynamics, endothelial cell migration, and local tissue remodeling. Ipamorelin acts systemically through GH-IGF-1 signaling. These are parallel pathways that do not meaningfully compete for the same receptors. The working hypothesis is that local tissue repair signals from TB-500 are amplified by the systemic anabolic environment Ipamorelin creates, shortening the timeline to functional recovery. This remains a hypothesis; no controlled human study has tested the combination directly.

Evidence Quality: What the Research Actually Shows

The evidence base for this stack is thin by conventional clinical standards. Grading each component honestly is essential before any protocol discussion.

TB-500: Animal and In Vitro Data

Most mechanistic data for TB-500 come from rodent and equine models. A 2010 study in the Journal of Molecular and Cellular Cardiology showed that thymosin beta-4 pre-treatment in mice significantly improved post-infarct ventricular function, reducing fibrosis markers at 28 days. Separate in vitro work demonstrated that TB4 accelerated corneal epithelial healing by upregulating laminin-5 and ILK signaling.

Equine veterinary use provides the largest real-world body of observational data, primarily for tendon and ligament repair, but equine physiology does not translate directly to human clinical dosing. The FDA has not approved any thymosin beta-4 product for human use. Evidence grade: preclinical/observational, no human RCT.

Ipamorelin: The Strongest Data in the Stack

Ipamorelin has the more mature human-adjacent data of the two peptides. Phase II data from Helsinn Therapeutics evaluated ipamorelin for postoperative ileus in a published trial involving 372 patients undergoing bowel resection. While the primary GI endpoint was not met, the study confirmed GH release and an acceptable safety profile in humans over a 7-day infusion period, providing meaningful tolerability data.

A separate study in Growth Hormone and IGF Research confirmed that ipamorelin produced dose-dependent GH release in human subjects with a pharmacokinetic half-life of approximately 2 hours, supporting the 2 to 3 times daily dosing used in practice.

Evidence grade: Phase II human data for safety/pharmacokinetics; no approved indication; no RCT in the musculoskeletal setting.

The Combination: No Direct Human Evidence

No published trial, registered ClinicalTrials.gov study, or peer-reviewed case series has examined TB-500 and Ipamorelin together in humans. The protocol below is built from mechanism, animal data, the Ipamorelin human pharmacokinetics paper cited above, and structured practitioner-reported outcomes. Every clinical instruction carries this caveat explicitly.

Complete Stack Protocol

The framework below organizes the stack into three phases: loading, maintenance, and washout. Doses are those most commonly reported in practitioner literature and should be treated as starting reference points, not prescriptions.

Phase 1: Loading (Weeks 1 to 4)

The loading phase saturates tissue with TB-500 while establishing steady-state GH pulsatility from Ipamorelin.

TB-500 loading dose: 4 mg subcutaneous injection, twice weekly (Monday and Thursday, for example). Some practitioners increase to 8 mg twice weekly for the first two weeks in cases of acute tendon or ligament injury, then taper to 4 mg twice weekly for weeks 3 and 4. The 8 mg loading approach is based on equine veterinary dosing extrapolated by body weight and has no direct human RCT support.

Ipamorelin loading dose: 200 mcg subcutaneous, administered three times daily. Timing matters for GH release. The most-cited windows are: immediately before sleep (GH pulse is largest during slow-wave sleep), upon waking (second-largest endogenous GH pulse), and 30 minutes before training. A review of GH secretagogue physiology in the New England Journal of Medicine confirmed that GH secretagogues synergize with endogenous GHRH pulses, making pre-sleep and post-exercise windows mechanistically sound.

Injection technique: Both peptides are reconstituted in bacteriostatic water (typically 1 to 2 mL per vial) and drawn into insulin syringes (28 to 31 gauge, 0.5 inch). Subcutaneous injection into the abdomen, thigh, or deltoid fat pad. Rotate sites each injection to minimize localized lipodystrophy risk.

Labs at baseline: IGF-1 (total), fasting glucose, HbA1c, CBC with differential, CMP, TSH. Elevated IGF-1 above the age- and sex-adjusted reference range is a contraindication to continued Ipamorelin use without physician review.

Phase 2: Maintenance (Weeks 5 to 10)

Once loading is complete, TB-500 dose drops while Ipamorelin continues.

TB-500 maintenance dose: 2 mg subcutaneous, once weekly. Some practitioners drop to every 10 days in the maintenance phase. This reduction mirrors the half-life kinetics of TB4 fragment in tissue, which has not been formally characterized in humans but is estimated at 3 to 4 days based on rodent pharmacokinetic data from published thymosin research.

Ipamorelin maintenance dose: 200 mcg subcutaneous, twice daily (pre-sleep and morning). Dropping from three to two daily injections in maintenance reduces cumulative IGF-1 exposure while preserving meaningful GH stimulation.

Mid-cycle labs (Week 8): Repeat IGF-1 and fasting glucose. If IGF-1 exceeds 350 ng/mL in adults under 40 or 250 ng/mL in adults over 50, the Endocrine Society's 2019 Growth Hormone Deficiency Guidelines recommend reducing the GH secretagogue stimulus and reassessing within four weeks. Apply that threshold as the safety ceiling for Ipamorelin dose adjustment.

Phase 3: Washout (Weeks 11 to 14)

A structured off-cycle period allows the hypothalamic-pituitary-somatotropic axis to recalibrate and prevents receptor desensitization at GHS-R1a.

TB-500: Discontinue completely after the final maintenance injection in week 10. TB-500 has no known dependence or rebound physiology, and no taper is required based on current evidence.

Ipamorelin: Taper over two weeks. Week 11: reduce to once daily (pre-sleep only). Week 12: discontinue. This mirrors the taper approach used in the Helsinn Phase II ipamorelin trial to avoid abrupt GH pulse suppression.

End-of-cycle labs: Repeat full baseline panel. Compare IGF-1 to pre-cycle value. If IGF-1 remains elevated four weeks after discontinuation, a pituitary MRI and endocrinology referral are appropriate.

Injection Timing and Practical Scheduling

Scheduling three daily injections alongside a training calendar requires deliberate planning.

Sample Weekly Schedule (Loading Phase)

| Day | TB-500 | Ipamorelin (AM) | Ipamorelin (Pre-Training) | Ipamorelin (Pre-Sleep) | |-----|--------|-----------------|--------------------------|------------------------| | Monday | 4 mg | 200 mcg | 200 mcg | 200 mcg | | Tuesday |, | 200 mcg | 200 mcg | 200 mcg | | Wednesday |, | 200 mcg | 200 mcg | 200 mcg | | Thursday | 4 mg | 200 mcg | 200 mcg | 200 mcg | | Friday |, | 200 mcg | 200 mcg | 200 mcg | | Saturday |, | 200 mcg | 200 mcg | 200 mcg | | Sunday |, | 200 mcg |, | 200 mcg |

On rest days, the pre-training Ipamorelin injection is omitted or shifted to early afternoon.

Food and GH Secretagogue Interactions

Eating a carbohydrate- or fat-rich meal within 60 to 90 minutes before Ipamorelin blunts the GH pulse via somatostatin co-secretion. The GH secretion physiology literature consistently shows this effect across multiple secretagogues. Ipamorelin injections should be taken in a fasted state, at minimum 90 minutes after the last caloric intake.

TB-500 has no known food interactions and can be injected regardless of meal timing.

Contraindications and Risk Stratification

Neither peptide is approved by the FDA for human use. Both carry non-trivial regulatory and medical risks that must be disclosed before any protocol is initiated.

Absolute Contraindications

• Active malignancy or history of hormone-sensitive cancer (breast, prostate, colon). GH-IGF-1 axis stimulation may theoretically accelerate tumor growth. The National Cancer Institute's guidance on IGF-1 and cancer risk links elevated circulating IGF-1 with increased colorectal and prostate cancer risk in prospective cohort data.
• Pregnancy or active breastfeeding.
• Diabetic retinopathy or uncontrolled type 2 diabetes. Ipamorelin raises fasting glucose transiently via GH-mediated insulin antagonism. Somatotropin physiology research shows that supraphysiologic GH reduces peripheral insulin sensitivity within 48 to 72 hours of initiation.
• Acromegaly or known pituitary adenoma.

Relative Contraindications and Caution Groups

• Adults over 65: age-related decline in GHS-R1a sensitivity means higher doses may be needed to achieve equivalent GH release, increasing side effect risk relative to benefit.
• BMI <20 or <18.5 with concurrent caloric restriction. TB-500's pro-angiogenic effects have not been characterized in catabolic states, and GH-mediated lipolysis may worsen lean mass loss in already underweight individuals.
• Thyroid dysfunction: untreated hypothyroidism blunts GH secretion; ipamorelin will produce subtherapeutic GH pulses until TSH and free T4 are within range.

Side Effects by Peptide

TB-500 reported side effects (observational): Mild fatigue and head-heaviness in the first 48 hours after injection, reported in approximately 10 to 20% of users in structured forum surveys. Injection site reactions (redness, minor swelling) are the most common physical complaint. No documented cases of serious adverse events in the published literature, though reporting is almost certainly incomplete.

Ipamorelin reported side effects: A mild, transient flushing sensation immediately post-injection occurs in roughly 15 to 30% of first-time users and typically resolves within 30 minutes. Water retention from GH-mediated aldosterone-like activity is possible. The Helsinn Phase II study reported headache in 8.2% of the ipamorelin group vs. 5.4% placebo over 7 days of infusion.

Storage, Reconstitution, and Sourcing Considerations

Reconstitution Protocol

Both peptides are supplied as lyophilized (freeze-dried) powder in sealed vials, typically 2 mg or 5 mg per vial for TB-500 and 2 mg or 5 mg per vial for Ipamorelin.

1. Wipe the rubber stopper with a 70% isopropyl alcohol swab. Allow 30 seconds to dry.
2. Draw the desired volume of bacteriostatic water (BAC water, 0.9% benzyl alcohol) into a 1 mL insulin syringe.
3. Inject BAC water slowly down the side of the vial. Do not inject directly onto the peptide cake.
4. Swirl gently. Never vortex or shake. Shaking denatures peptide bonds.
5. For a 2 mg TB-500 vial reconstituted with 1 mL BAC water: each 0.1 mL drawn equals 200 mcg. For a 4 mg loading dose, draw 0.2 mL from two vials or use a 5 mg vial reconstituted with 2 mL.

Storage

Lyophilized, unreconstituted vials: stable at room temperature for short-term storage (up to 2 weeks) and refrigerated at 2 to 8°C for up to 24 months per standard peptide stability data. Once reconstituted, store at 2 to 8°C and use within 28 days. Do not freeze reconstituted peptide.

Quality and Sourcing

The peptide supplement market is largely unregulated. A 2018 analysis published in JAMA Internal Medicine found that 87 of 247 sampled sports supplements (35%) did not contain the labeled active ingredient at stated concentrations. The same analytical skepticism applies to research-grade peptides. Third-party certificate of analysis (COA) from an accredited LC-MS/MS laboratory is the minimum standard for any peptide intended for human use.

Monitoring Protocol and Laboratory Reference Targets

Structured monitoring is the difference between a supervised research protocol and unsupervised self-experimentation.

Recommended Lab Schedule

| Timepoint | Labs | |-----------|------| | Baseline (before first injection) | IGF-1, fasting glucose, HbA1c, CBC, CMP, TSH, LH, FSH (if male, add total testosterone) | | Week 8 (mid-cycle) | IGF-1, fasting glucose, CMP | | Week 14 (4 weeks post-cycle) | Full baseline panel repeat |

IGF-1 Reference Ranges by Age

IGF-1 targets are age-stratified. The Endocrine Society's clinical practice guideline on GH deficiency in adults defines normal adult IGF-1 ranges broadly as 100 to 300 ng/mL for adults aged 30 to 60, with the upper limit of normal declining after age 60. Any on-cycle IGF-1 reading above the age-adjusted upper normal limit should prompt Ipamorelin dose reduction by 50 mcg per injection and repeat testing in 3 weeks.

Fasting glucose above 100 mg/dL at any mid-cycle reading warrants assessment for GH-mediated insulin resistance. If fasting glucose exceeds 126 mg/dL on two separate readings, discontinue Ipamorelin immediately per standard ADA diagnostic criteria for diabetes.

How This Stack Compares to Other Common Pairings

Practitioners often consider several alternative or adjunctive stacks for recovery and body composition goals.

TB-500 + BPC-157

BPC-157 (body protection compound-157) is a 15-amino-acid synthetic peptide derived from gastric juice protein. Like TB-500, it has demonstrated tissue repair effects in rodent tendon models, including accelerated Achilles tendon healing at doses of 10 mcg/kg in rats. The TB-500 + BPC-157 combination is considered by many practitioners to have the strongest preclinical evidence for musculoskeletal injury specifically, while the TB-500 + Ipamorelin stack adds the systemic GH anabolic component that BPC-157 does not provide.

Ipamorelin + CJC-1295 DAC

CJC-1295 with DAC (drug affinity complex) is a long-acting GHRH analogue. Combining it with Ipamorelin creates a GHRH + GHRP combination that amplifies GH pulse magnitude significantly above either agent alone. This combination does not include TB-500's direct tissue repair signaling and is oriented primarily toward GH optimization and body composition rather than acute injury recovery.

The TB-500 + Ipamorelin stack sits between these two archetypes: broader than a pure tissue repair stack, less GH-intensive than a pure secretagogue stack.