Base Peptide Guide - December Edition
Base Peptides: December Research Newsletter
A year-end look at high-interest research peptides across metabolism, weight loss, cognition, healing, and healthy aging — plus regulatory updates and a deep dive into a pivotal clinical trial.
Research-use only notice: All materials discussed here are for educational review of published literature. Base Peptides products are sold strictly for laboratory research use only and are not intended for human consumption, medical, diagnostic, or therapeutic use.
Research Spotlight: Key Peptides by Category
Tesamorelin
Tesamorelin is a synthetic analogue of growth hormone–releasing hormone (GHRH) that has been studied for its effects on visceral adipose tissue (VAT), body composition, and metabolic markers. In its drug form, tesamorelin is FDA-approved in the U.S. to reduce excess abdominal fat in adults with HIV-associated lipodystrophy.
Research appeal: Models investigating VAT reduction, hepatic fat, lipid profiles, and growth-hormone axis modulation in metabolic dysfunction.
Representative case uses in research settings:
- Mechanistic studies on GHRH analogues and body-fat distribution.
- Exploring effects on triglycerides, insulin resistance, or NAFLD models.
- Comparative work versus other metabolic or lipolytic interventions.
Retatrutide
Retatrutide is a next-generation triple agonist that targets GLP-1, GIP, and glucagon receptors. In a phase 2 randomized, placebo-controlled trial in adults with obesity, 48 weeks of treatment produced substantial body-weight reductions, with the highest dose arm seeing mean losses above 20% of baseline weight.
Research appeal: Multi-receptor agonism allows exploration of appetite regulation, energy expenditure, and metabolic disease endpoints beyond traditional single-agonist GLP-1 compounds.
Representative case uses in research settings:
- Preclinical obesity models comparing triple- vs dual-agonist strategies.
- Liver and cardiovascular risk-factor profiling in metabolic-syndrome models.
- Dose–response work on energy expenditure and thermogenesis pathways.
Retatrutide remains an investigational drug candidate and is not FDA-approved at this time. Any Base Peptides retatrutide products are offered solely for laboratory research use.
Semax
Semax is a synthetic peptide derived from an ACTH (4–10) fragment. It has been used in Russia and Eastern Europe as a prescription medication for cognitive and neurological indications and appears on the Russian list of vital and essential medicines.
Experimental work has shown neuroprotective and neurorestorative effects in ischemic brain models, including improved functional recovery after experimental stroke and modulation of gene expression related to inflammation and neuroplasticity.
Research appeal: Mechanistic studies in neuroinflammation, synaptic plasticity, learning and memory, and ischemia–reperfusion injury.
Representative case uses in research settings:
- Rodent models of ischemic stroke and recovery paradigms.
- Gene-expression profiling of neurotrophic and inflammatory pathways.
- Cognitive-task performance and learning assays under stress or injury.
Thymulin
Thymulin is a thymic peptide complex historically studied for its role in immune– neuroendocrine communication. Early and more recent work has linked thymulin levels to immune deficiency and autoimmune states, with evidence that it can modulate T-cell function and inflammatory signaling.
In preclinical pain and neuroinflammation models, long-term thymulin treatment has been shown to reduce microglial activation and attenuate inflammatory pain signaling.
Research appeal: Bridging innate and adaptive immunity with neuroendocrine pathways, and exploring how thymic peptides affect inflammation, tissue repair, and pain.
Representative case uses in research settings:
- Immune-reconstitution and thymic-function models.
- Chronic pain and neuroinflammation assays.
- Co-administration with other thymic peptides in combination studies.
SS-31 (Elamipretide)
SS-31 (elamipretide) is a mitochondria-targeted tetrapeptide that interacts with cardiolipin in the inner mitochondrial membrane. It has been studied for its ability to improve mitochondrial function, reduce oxidative stress, and support energetics in tissues with high metabolic demand, such as heart and skeletal muscle.
In clinical research on Barth syndrome, long-term elamipretide exposure (48 weeks) has been associated with improvements in 6-minute walk distance, symptom scores, and cardiac stroke volume in affected patients, highlighting mitochondrial modulation as a therapeutic target.
Research appeal: A tool compound for interrogating mitochondrial dysfunction, cardiolipin integrity, and age-related decline in cellular energetics.
Representative case uses in research settings:
- Cardiac and skeletal-muscle models of mitochondrial disease.
- Age-related sarcopenia and frailty research.
- Oxidative-stress and mitochondrial-biogenesis pathways.
Mainstream Peptide & Regulatory Updates
Peptides have moved firmly into the mainstream conversation, especially around GLP-1–based weight-loss drugs and online sales. Recent regulatory updates highlight how important it is to respect the boundary between research use and human-use claims:
- End of GLP-1 shortages & impact on compounding: After multi-year supply constraints, the FDA has declared shortages resolved for major branded products such as semaglutide and tirzepatide. As supply stabilizes, temporary flexibilities for compounding are being rolled back and compounders are being directed to stop producing certain GLP-1 copies.
- Guidance on peptide drug development: FDA guidance documents for peptide drug products outline expectations around immunogenicity, bioanalytical methods, and equivalence considerations for synthetic peptides, reinforcing that even “simple” peptides are regulated as drug products when intended for therapeutic use.
- Global enforcement against grey-market peptides: Regulators outside the U.S. are cracking down on influencer-driven sales of injectable peptides such as melanotan II and weight-loss compounds that are “not approved for human use,” particularly when posts include dosing advice or before-and-after photos.
Clinical Trial Spotlight: Semaglutide in Obesity (STEP 1)
Many labs working with GLP-1–related compounds look to human data to help frame their preclinical questions. One of the most influential trials in this area is the STEP 1 trial, which evaluated once-weekly semaglutide 2.4 mg as a drug for chronic weight management.
Trial Design
STEP 1 was a double-blind, randomized, placebo-controlled phase 3 trial that enrolled 1,961 adults with obesity (BMI ≥30) or overweight (BMI ≥27) with at least one weight-related comorbidity, but without diabetes. Participants were assigned to semaglutide 2.4 mg once weekly or placebo, both combined with lifestyle intervention, for 68 weeks.
Key Outcomes
- Mean body-weight change at week 68 was −14.9% with semaglutide versus −2.4% with placebo, a difference of 12.4 percentage points.
- A large majority of participants on semaglutide achieved clinically significant weight-loss thresholds (≥5%, ≥10%, ≥15% of baseline weight), with effect sizes that exceeded earlier anti-obesity medications.
- Improvements were also seen in cardiometabolic risk markers, including waist circumference, blood pressure, and selected lipid parameters.
Why It Matters for Research
STEP 1 and subsequent STEP trials helped establish GLP-1 analogues as a powerful tool for pharmacologic weight management, with magnitudes of weight loss approaching those seen with bariatric surgery in some cohorts. For laboratories, semaglutide and related incretin mimetics provide rich models to study:
- Central versus peripheral mechanisms of appetite and satiety.
- Long-term effects of GLP-1 signaling on adipose tissue biology.
- Interactions between weight loss, cardiovascular risk, and inflammatory pathways.