The best peptides for longevity research

The six most studied longevity peptides available for research in 2026 are Epitalon, GHK-Cu, MOTS-c, NAD+, tesamorelin and somatropin, each mapped to specific hallmarks of ageing according to López-Otín's hallmarks framework [3].

Longevity peptides: the essentials

• In 2026 no peptide is authorised as a longevity or anti-ageing medicine; every compound discussed here is for research use only [1]
• López-Otín's hallmarks framework (telomere biology, mitochondrial dysfunction, epigenetic alterations, senescence, inflammaging and others) provides the mechanistic anchor for choosing which peptide to study [3]
• NAD+ and MOTS-c converge on the AMPK/NAD+/SIRT1/PGC-1α axis; GHK-Cu modulates more than 4,000 genes; Epitalon targets telomerase; tesamorelin and somatropin act on the somatotropic axis [2][4][5][6]
• Human data on longevity endpoints (epigenetic age, all-cause mortality) are lacking for every compound in the 2024–2026 source corpus
• Combine peptides across hallmarks, not within a single hallmark, to avoid redundancy; NAD+ + MOTS-c and GHK-Cu + NAD+ are mechanistically plausible pairings [3]

What this guide covers

This guide deals with:

• A mechanism-by-mechanism breakdown of each compound following López-Otín's hallmarks framework [3]
• The current regulatory position: no peptide is authorised as a longevity or anti-ageing medicine in 2026 [1]
• A comparison table of signalling-pathway target, level of evidence and purchasing considerations for research
• Honest pointers to where human data are missing, including MOTS-c metabolic outcomes and independent replication of Khavinson's work on Epitalon and telomerase [6]

We have written this for people evaluating compounds in 2026, not for clinical self-administration.

Top picks: best longevity peptides for research (2026)

Ranked by the strength and breadth of their mechanistic mapping to López-Otín's hallmarks of ageing, these are the compounds we rate most highly in 2026 for longevity research. Each pick is a research compound from the Body Pharm catalogue, for laboratory and analytical purposes only; none is authorised as a longevity or anti-ageing medicine [1].

• Best overall / broadest mechanism: GHK-Cu. The copper tripeptide modulates the expression of more than 4,000 genes and shows a documented decline in plasma with age; it spans the epigenetic alterations and inflammaging hallmarks and has the broadest transcriptional footprint of the group.
• Best for mitochondrial-axis research: MOTS-c. The mitochondrially encoded peptide explicitly mapped to AMPK/NAD+/SIRT1/PGC-1α signalling and the mitochondrial dysfunction hallmark, with a clear age-related decline curve in mice.
• Best cofactor pairing / redox baseline: NAD+. A redox coenzyme central to sirtuin and PARP activity; the standard companion to MOTS-c on the shared AMPK/NAD+/SIRT1/PGC-1α axis. (Strictly speaking, it is a nucleotide, not a peptide.)
• Best tool for the somatotropic axis: Tesamorelin 32 mg. The best clinically validated GHRH analogue, restoring pulsatile GH architecture without supraphysiological exposure; mapped to the loss of proteostasis hallmark.
• Best direct GH reference: somatropin. Recombinant GH for protocols that set the somatotropic axis directly; the downstream comparator for GHRH analogue work. Not currently available in the Body Pharm catalogue.

In 2026, human data on longevity endpoints (epigenetic age, all-cause mortality) are lacking for all of these compounds; choose according to the hallmark your protocol is studying. The full mechanism-by-mechanism breakdown follows below.

What are longevity peptides? (2026 definition)

Longevity peptides are short amino-acid sequences, typically 3 to 40 residues, or synthetic analogues, that modulate one or more biological pathways of ageing as defined by López-Otín's hallmarks framework [3]. They are distinct from generic "anti-ageing" cosmetic marketing because their classification rests on a measurable mechanistic target, such as telomere maintenance, mitochondrial biogenesis, autophagy, sirtuin signalling or senescent-cell clearance, and not on a downstream cosmetic claim [3].

The current scientific anchor is López-Otín's 2023 update in Cell, which expands the original 2013 list of hallmarks to twelve, adding disabled macroautophagy, chronic inflammation (inflammaging) and dysbiosis to the initial nine. This guide organises peptide biology directly onto that framework, mapping each compound to telomere biology, mTOR/autophagy, NAD+/sirtuin signalling, senescence/SASP, mitochondrial biogenesis, mitophagy, proteostasis and inflammaging [3].

How this differs from "anti-ageing" cosmetic peptides

A topical matrikine in a cosmetic serum and a research-grade mitochondrial peptide share the word "peptide" and almost nothing else. Longevity peptides, in the sense used here, are assessed on:

• A specific hallmark or pathway with peer-reviewed mechanistic data (for example, MOTS-c → AMPK/NAD+/SIRT1/PGC-1α) [2]
• A defined molecular target or receptor interaction, not a generic "skin rejuvenation" claim
• Preclinical or, where they exist, human biomarker endpoints, rather than consumer perception scores
• A documented sequence and synthesis route suitable for analytical characterisation

Regulatory classification

In 2026 no peptide is authorised as a longevity or anti-ageing medicine [1]. The compounds discussed here are sold solely for laboratory research; they are not authorised medicines for human use, and a supplier's "research use" labelling does not confer medicinal status [1]. Practical protocol resources, such as our NAD+ dosing protocol and the MOTS-c dosing guide, are written within that same in vitro research framework.

The 2026 hallmarks framework: how to choose a compound

Choose a peptide by matching its primary mechanism to the hallmark of ageing you want to study, not by the marketing claim. Each compound below has been mapped to López-Otín's list of hallmarks, whose axes include telomere biology, mTOR/autophagy, NAD+/sirtuin signalling, senescence, mitochondrial biogenesis, mitophagy, proteostasis and inflammaging [3].

The practical question for a 2026 research protocol is: which axis am I studying, and does the chosen peptide have a documented mechanism on that axis? A compound positioned on mitochondrial dysfunction (MOTS-c) is not interchangeable with one positioned on telomere attrition (Epitalon), even if both appear in the same supplier catalogue.

Mechanism and supply comparison table

The six most studied and available longevity peptides in 2026, mapped to their primary and secondary hallmark targets:

How to read the table for protocol design

Read it by row, not by column. If the research question concerns mitochondrial biogenesis under a metabolic-stress model, both NAD+ and MOTS-c are candidates; the AMPK/NAD+/SIRT1/PGC-1α axis is the shared mechanistic substrate [2][3]. If the question concerns telomerase activity in cultured cells, Epitalon is the only row that maps cleanly to telomere attrition, although no independent replication of Khavinson's original telomerase findings has been identified in the 2026 source corpus [6].

Pairing across hallmarks (for example, working with NAD+ precursors alongside MOTS-c) is a frequently discussed research hypothesis, because both converge on the same signalling cascade. No direct controlled study of the combination with ageing endpoints has been found in the 2026 literature reviewed here.

NAD+: mitochondrial research in 2026

NAD+ is a redox coenzyme central to sirtuin and PARP activity, mitochondrial biogenesis and the AMPK/NAD+/SIRT1/PGC-1α axis, which López-Otín's hallmarks framework places at the centre of the deregulated nutrient sensing and mitochondrial dysfunction hallmarks [3]. Strictly speaking it is a nucleotide and not a peptide, but it appears in almost every serious longevity research stack, because it shares its signalling substrate with MOTS-c and with the GH-axis peptides discussed below [2].

Core mechanistic anchors for research design in 2026:

• Sirtuin activation: SIRT1 and SIRT3 are NAD+-dependent deacetylases. Intracellular NAD+ availability limits their activity on PGC-1α and FOXO targets [3].
• PARP competition: DNA damage-driven PARP1 activity consumes NAD+ and creates a substrate sink that worsens the age-associated decline [3].
• Mitochondrial biogenesis: PGC-1α, downstream of SIRT1, drives mitochondrial DNA transcription and respiratory-chain assembly, the same endpoint on which MOTS-c converges [2][3].
• NAD+ decline with age: circulating and tissue NAD+ falls across the human lifespan, a finding López-Otín's 2023 review treats as established basic biology rather than a contested claim [3].

Human evidence 2024–2026

Human data from 2024 to 2026 on oral NAD+ precursors consistently describe increases in circulating NAD-related metabolites. They do not yet show a reproducible change in validated biological age clocks or in telomere endpoints. The defensible reading in 2026: NAD+ interventions are biomarker-active at the metabolite level and mechanistically tied to the sirtuin axis [3]. They have not been shown clinically to slow human ageing.

To date no NAD+ intervention has shown a reduction in epigenetic age in humans.

Sourcing NAD+ for research (2026)

Body Pharm lists NAD+ 1000 in its 2026 catalogue as a research compound, alongside MOTS-c in the mitochondrial pathway category. The NAD+ 1000 pen carries 1,000 mg in total in a 3 ml cartridge, and the dose dial reads directly in milligrams. For protocol design, the NAD+ dosing protocol covers dialled doses and the frequency considerations specific to direct NAD+. The MOTS-c dosing guide is the logical complement when setting up studies around the shared AMPK/SIRT1/PGC-1α cascade [2]. No NAD+ product is authorised as a longevity or anti-ageing medicine; a supply labelled as a research product is not equivalent to medicinal status [1].

MOTS-c: the mitochondrially encoded peptide

MOTS-c is a 16-amino-acid mitochondrial-derived peptide (MDP) located in the 12S rRNA region of mitochondrial DNA, which sets it apart biologically from the synthetic and nuclear-encoded peptides that dominate the longevity research field [2]. Lee et al. first identified MOTS-c in 2015 in Cell Metabolism and characterised its role in regulating insulin sensitivity and metabolic homeostasis via AMPK activation. Reynolds et al. (Nature Communications, 2021) then showed that circulating MOTS-c rises acutely with exercise in humans [7]; the decline of its levels with age has been documented in mice [2]. That is why the compound is often described as a candidate endogenous exercise mimetic [7].

What MOTS-c actually does at the cellular level

The mechanistic profile that makes MOTS-c interesting to longevity researchers in 2026 includes four functions:

• AMPK activation, which drives glucose uptake and fatty-acid oxidation in skeletal muscle (Lee et al., 2015) [2]
• Insulin sensitisation in mouse models of diet-induced obesity, independent of weight changes (Lee et al., 2015) [2]
• Exercise-mimetic signalling: circulating MOTS-c rises in humans with acute exercise (Reynolds et al., 2021) [7] and declines with age in mice (Lee et al., 2015) [2]
• Nuclear translocation under metabolic stress, in which MOTS-c regulates nuclear gene expression for antioxidant and metabolic responses (Kim et al., 2018) [10]

Its integration into the NAD+/SIRT1/PGC-1α axis explains why MOTS-c and NAD+ come up again and again in the same protocol discussions. MOTS-c activates AMPK, upstream of NAD+/SIRT1/PGC-1α signalling, which places it alongside (not as redundant with) direct NAD+ administration [2].

State of the human data in 2026

Human efficacy data for exogenous MOTS-c administration remain sparse. In the source corpus used for this guide we have identified no human clinical study published between 2024 and 2026 on exogenous MOTS-c with metabolic or ageing endpoints. The defensible position in 2026: MOTS-c is a high-interest research compound with compelling preclinical biology and a clear age-related decline curve in mice [2]. The efficacy of dosing in humans has not yet been demonstrated.

The endogenous decline curve in mice (Lee et al., 2015) provides a mechanistic rationale for studying it, even without proof of exogenous benefit [2].

Research supply and protocol design

Interest in MOTS-c is low in volume but high in intent: almost exclusively serious researchers and longevity-focused clinical staff designing protocols. For the practical considerations of dialled dose and frequency, the MOTS-c dosing guide is the companion resource. The NAD+ dosing protocol is the logical complement for any study built around the shared AMPK/SIRT1/PGC-1α cascade [2].

GHK-Cu: copper tripeptide and gene expression

GHK-Cu is a naturally occurring plasma tripeptide (glycyl-L-histidyl-L-lysine bound to copper) that modulates the expression of more than 4,000 human genes, making it the broadest transcriptional regulator in the longevity peptide group [4]. Pickart first isolated GHK in 1973 as a plasma factor with activity on liver-cell survival [11]. The copper-complex form is the one most 2026 research protocols take as their reference.

The age-related decline curve is steep and well documented: plasma GHK averages around 200 ng/ml at age 20 and falls to around 80 ng/ml by age 60 (Pickart, 2008) [12]. That drop coincides with the documented decline in wound-healing capacity and in tissue regenerative signalling, which is why GHK-Cu is positioned on the proteostasis and inflammaging arms of the hallmarks framework [3].

Mechanistic profile

Four mechanisms recur across Pickart and Margolina's 2018 synthesis in the International Journal of Molecular Sciences [4]:

• Tissue remodelling and collagen synthesis, through upregulation of decorin, fibroblast activation and modulation of matrix metalloproteinases
• Anti-inflammatory gene modulation, with downregulation of NF-κB-coupled inflammatory transcripts, relevant to inflammaging [4]
• Upregulation of antioxidant enzymes, including support for the SOD and catalase pathways
• Broad transcriptional reset, where the 4,000-plus gene signature includes DNA-repair and stem cell-associated programmes [4]

Research contexts in 2026

Research interest in GHK-Cu splits into two lines. The dermal research line uses topical or low-dose subcutaneous protocols to study collagen and barrier outcomes. The systemic line, more relevant to longevity researchers, studies subcutaneous administration for inflammaging and proteostasis endpoints and often combines GHK-Cu with mitochondrial-axis or NAD+ compounds in the protocol design. Human studies on longevity endpoints are missing from the 2024–2026 source corpus used here.

The documented plasma decline with age (Pickart, 2008) offers a mechanistic entry point for study [12]. GHK-Cu is one of only two compounds in this guide (together with Epitalon) with a clearly documented age-associated plasma decline measured in nanograms per millilitre. That is the single strongest argument for including it in any longevity research panel in 2026.

If you are combining GHK-Cu with mitochondrial work, the MOTS-c dosing guide and the NAD+ dosing protocol are the complementary methodological references.

Tesamorelin: research with GHRH analogues

Tesamorelin is an analogue of human growth hormone-releasing hormone (GHRH) modified with trans-3-hexenoic acid, designed to achieve serum stability beyond the sub-10-minute half-life of endogenous GHRH. The N-terminal acyl modification resists cleavage by dipeptidyl peptidase IV, so the 44-amino-acid peptide reaches the pituitary somatotroph cells intact and stimulates pulsatile GH secretion rather than introducing exogenous GH directly.

This mechanistic distinction matters to longevity researchers. Unlike somatropin, which bypasses pituitary feedback and sets the somatotropic axis in open loop, tesamorelin preserves the negative feedback from somatostatin and IGF-1. That produces GH pulses closer to youthful endogenous secretion patterns. The subsequent rise in IGF-1 is the measured biomarker, and visceral adipose tissue (VAT) is the most cited functional endpoint.

Clinical evidence base

The reference citation remains Falutz and colleagues in the New England Journal of Medicine (2007), a 26-week randomised controlled trial in HIV-associated abdominal fat accumulation that reported a 15.2% reduction in VAT versus a 5.0% increase on placebo, with IGF-1 increases [8]. No 2024–2026 study in the source corpus used here replaces that trial as the primary clinical reference. No human studies on longevity endpoints (epigenetic age, all-cause mortality) have been published with tesamorelin.

The Corpas et al. review places GHRH analogues within the decline of the somatotropic axis that accompanies ageing, with reduced GH pulse amplitude being one component of the broader endocrine senescence phenotype [5]. Tesamorelin is the best clinically validated tool for restoring that pulse architecture without supraphysiological GH exposure.

The VAT reduction in the Falutz study (2007) provides a functional biomarker relevant to metabolic ageing, even without direct epigenetic age data [8].

Supply in 2026

Body Pharm supplies tesamorelin as a pre-filled multi-dose pen of 32 mg in total, with a 3 ml cartridge that covers extended research protocols without changing units. The dose dial reads directly in milligrams. If you are comparing GHRH analogues with GHRH-plus-GHRP combinations, see the CJC-1295 vs. ipamorelin guide for the mechanistic contrasts. The tesamorelin dosing guide covers titration methodology.

If you are designing protocols that combine somatotropic work with mitochondrial work, pairing tesamorelin research with the MOTS-c dosing guide covers the intersection between the GH axis and mitochondrial biogenesis. Tesamorelin remains for research use only; there is no authorisation for longevity or anti-ageing indications [1].

Somatropin (HGH): growth hormone in longevity research

Somatropin is recombinant human growth hormone, a 191-amino-acid polypeptide whose sequence is identical to endogenous pituitary GH. It sits one step below the secretagogues already discussed: where tesamorelin stimulates the pituitary via the GHRH receptor and ipamorelin acts via the ghrelin/GHSR axis, somatropin bypasses pulsatile control entirely and delivers exogenous GH straight into the circulation. That distinction matters for protocol design, because the endogenous pulsatile architecture is lost and the IGF-1 elevation tends to be flatter and more sustained.

Somatopause, the age-associated decline in GH pulse amplitude and 24-hour GH production, was characterised in Corpas et al., Endocrine Reviews, 1993 [5], and remains the mechanistic rationale for studying GH restoration in older cohorts. López-Otín's hallmarks framework groups the decline of the GH/IGF-1 axis under deregulated nutrient sensing, which overlaps with mitochondrial and NAD+/sirtuin signalling [3].

Evidence base and historical context

Rudman et al., NEJM, 1990, described increases in lean mass [9] and decreases in adipose tissue in men over 60 who received recombinant GH for six months. That study is the most cited entry point in discussions of HGH and ageing, but it is 1990 data from a small cohort. Research in the decades since has been considerably more nuanced about the adverse-effect burden, the insulin-resistance signal and the absence of validated longevity endpoints. No 2024–2026 study in the source corpus used here shows a reduction in epigenetic age or an all-cause mortality benefit with exogenous somatropin.

The Rudman study (1990) remains the primary reference for functional outcomes, despite its age and limitations [9].

Supply in 2026

Somatropin is not currently available in the Body Pharm catalogue. If you are running mitochondrial or NAD+-axis work in parallel, cross-check dosing against the MOTS-c dosing guide and the NAD+ dosing protocol. The GH-IGF-1 axis interacts directly with the sirtuin and PGC-1α signalling described in the López-Otín review [3]. Somatropin has no authorisation for longevity or anti-ageing indications [1].

Epitalon: telomere research and epigenetic targets

Epitalon is a synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly, derived from the bovine pineal gland extract epithalamin, and is studied chiefly for telomerase activation and telomere lengthening in somatic cell models. It is mapped to the telomere attrition hallmark of the López-Otín framework [3].

The foundational in vitro work is Khavinson et al., Bulletin of Experimental Biology and Medicine, 2003, which describes telomerase activity and telomere elongation in human fetal fibroblasts exposed to the tetrapeptide [6]. Anisimov et al., 2003, described in mice treated with Epitalon an increase in maximum (not mean) lifespan, with no change in total spontaneous tumour incidence but less leukaemia development [13]. Both lines of evidence come largely from the Saint Petersburg Institute of Bioregulation and Gerontology, Khavinson's group. In the 2024–2026 source corpus reviewed for this guide, no replication by independent laboratories with human-relevant telomerase endpoints has been established.

What the evidence base actually shows in 2026

The Khavinson and Anisimov papers describe Epitalon as a telomere-targeting research peptide and as a tool for studying TERT/telomerase [6][13]. They stop short of presenting it as a validated geroprotector in humans. There is no authorisation of Epitalon as a longevity or anti-ageing medicine, and in 2026 no peptide holds any such authorisation [1].

Khavinson's original findings (2003) remain the primary mechanistic reference, with no confirmatory work from other laboratories in the current source corpus [6].

Supply note (October 2026)

As of October 2026, Body Pharm does not offer Epitalon. Anyone wanting to work with adjacent-pathway tools in the meantime can turn to the NAD+ dosing protocol and the MOTS-c dosing guide. Both sit on the sirtuin-mitochondrial axis, which overlaps with the telomere-maintenance biology described in the López-Otín review [3].

Longevity peptide stacks: considerations for the research protocol

Combining longevity peptides in research models is a hallmark-driven strategy: each compound is chosen to act on a different ageing axis, so that the combination covers more of the López-Otín framework than any single active compound could [3]. The López-Otín framework covers telomere maintenance, mTOR/autophagy, NAD+/sirtuin signalling, senescence/SASP, mitochondrial biogenesis, mitophagy, proteostasis and inflammaging. That is the conceptual basis used when designing multi-compound protocols [3].

Three pairings recur most often in the 2024–2026 literature reviewed for this guide:

NAD+ + MOTS-c (mitochondrial axis). Lee et al. describe MOTS-c as acting on AMPK signalling, upstream of the NAD+/SIRT1/PGC-1α axis, that is, the same signalling space occupied by NAD+ precursors [2]. Mechanistic plausibility is high. No direct controlled study of the combination with ageing endpoints has been identified in the source corpus reviewed. Protocol depth for each compound is in the NAD+ dosing protocol and the MOTS-c dosing guide.

GHK-Cu + NAD+ (epigenetic + redox). GHK-Cu's gene-expression modulation and copper-dependent redox activity sit alongside NAD+-driven sirtuin signalling. That targets two distinct hallmarks rather than duplicating one [3].

Tesamorelin + somatropin (GH axis, risk of redundancy). This pairing deserves an explicit warning. Tesamorelin is a GHRH analogue that stimulates endogenous GH release, while somatropin is recombinant GH itself. Using both at once carries a risk of redundant IGF-1 stimulation rather than additive benefit. Many guides leave that nuance out.

Stacking decisions in research call for mapping pathways before selecting compounds: pair across hallmarks, not within one, and document each endpoint independently. All references here concern in vitro and preclinical research contexts; in 2026 no peptide is authorised as a longevity medicine [1].

Buying longevity peptides: what to look for

Sourcing research-grade peptides comes down to four verifiable features: batch traceability, a per-batch HPLC purity certificate, temperature-controlled shipping and a dispatch point in Spain that avoids customs risk. If any one of them is missing, the supply should be regarded as analytically unreliable regardless of price.

Peptides sold for research and analytical purposes fall outside the medicinal product framework, provided the seller makes no medical or anti-ageing claims [1]. The compounds themselves are not authorised medicines, and in 2026 no peptide is authorised as a longevity intervention [1]. The regulatory boundary runs through the marketing language and the intended purpose, not through the molecule.

The supply format

Every compound in the Body Pharm catalogue is supplied as a sterile, pre-filled multi-dose pen for subcutaneous injection, with a 3 ml cartridge and a dose dial that reads directly in milligrams. They arrive ready to use. That matters when you are running a multi-week protocol and want every administration to be quantitatively identical: the figure you dial is the figure that gets recorded, from the first dose to the last. If a compound interests you and it does not exist in pen format, it is not in this catalogue.

What to check before buying

• Certificate of analysis (HPLC) tied to the specific batch number of the pen, not a generic product-level certificate
• Storage and shipping conditions: between 2 and 8 °C protected from light, 24 months unopened and 12 months from the first puncture, with up to 30 days at room temperature (30 °C maximum) if no fridge is available; let it reach room temperature before injecting and do not freeze. The supplier should state storage conditions, shipping route and transit time transparently
• Delivery address in Spain: domestic shipping avoids the customs and import risks that affect orders from third countries
• No medical claims in the listing: compliant sellers describe research purposes only and do not promise anti-ageing results in humans [1]

Body Pharm's 2026 catalogue is built on the sealed multi-dose pen model for NAD+ 1000, MOTS-c, GHK-Cu and Tesamorelin 32 mg. Batch-traceable HPLC documentation and shipping to Spain are the standard. Protocol details for the two most frequently combined compounds are in the NAD+ dosing protocol and the MOTS-c dosing guide.

Frequently Asked Questions: longevity peptides

Which is the best-studied longevity peptide?

Epitalon is among the most cited longevity peptides in the gerontology literature, with a research history going back to Khavinson's work with pineal gland extract and with Khavinson et al.'s 2003 telomerase work as the mechanistic reference [6]. No replication of the original telomerase findings by independent laboratories has been established in the current source corpus, so "best studied" should not be read as "best proven".

Is NAD+ a peptide?

No. NAD+ (nicotinamide adenine dinucleotide) is a coenzyme, not a peptide. It is grouped with longevity peptides in research catalogues because it sits on the same NAD+/sirtuin signalling axis that MOTS-c, Epitalon and other peptides modulate via AMPK/SIRT1/PGC-1α [3]. Practical dosing details are in the NAD+ dosing protocol.

Can I buy GHK-Cu in Spain?

Yes, in 2026 GHK-Cu is available from research-material suppliers, including Body Pharm, which offers it alongside MOTS-c, NAD+ 1000 and Tesamorelin 32 mg with research labelling. No GHK-Cu product is authorised as a medicine, so its lawful supply depends on its classification as a research product and not on therapeutic claims [1].

What is the difference between tesamorelin and somatropin?

Tesamorelin is a GHRH analogue that stimulates endogenous growth hormone release from the pituitary, whereas somatropin is recombinant human growth hormone itself, administered exogenously [5]. Tesamorelin preserves pulsatile GH signalling; somatropin produces direct, supraphysiological serum GH levels.

Are longevity peptides legal in Spain?

In 2026 no peptide is authorised as a longevity or anti-ageing medicine [1]. Compounds sold as research or analytical products may be supplied for non-medical research purposes. Marketing them for anti-ageing results in humans is incompatible with their status as unauthorised products [1].

What does "research use only" mean?

It means the product is supplied for in vitro or analytical work and is not authorised as a medicine for human use [1]. The regulatory boundary runs through intended purpose and marketing language, not through the molecule itself. Protocol context for one widely used research compound is in the MOTS-c dosing guide.

Next steps for your research

Start by identifying the hallmark of ageing your protocol targets. Use the mechanism and supply comparison table to choose a primary compound, then turn to the corresponding dosing guide (NAD+, MOTS-c or tesamorelin) for dialled-dose and administration details. If you are combining compounds, pair across hallmarks rather than within one, to avoid redundancy. Before buying, check batch traceability and HPLC certification and make sure your supplier ships to Spain and states storage and shipping conditions transparently. For any multi-compound protocol, the NAD+ dosing protocol and the MOTS-c dosing guide provide the mechanistic and practical grounding for the compounds most often combined in longevity research in 2026.

Sources

1. Directive 2001/83/EC, Article 1: definition of a medicinal product by presentation and by function; consolidated text on EUR-Lex. eur-lex.europa.eu — legal basis for a reagent labelled "research use only" remaining subject to pharmaceutical regulation if it is presented for human use.
2. Lee C, et al. The Mitochondrial-Derived Peptide MOTS-c Promotes Metabolic Homeostasis and Reduces Obesity and Insulin Resistance. Cell Metab. 2015. pubmed.ncbi.nlm.nih.gov/25738459
3. López-Otín C, et al. Hallmarks of aging: an expanding universe. Cell. 2023. pubmed.ncbi.nlm.nih.gov/36599349
4. Pickart L, Margolina A. Regenerative and Protective Actions of the GHK-Cu Peptide in the Light of the New Gene Data. Int J Mol Sci. 2018;19(7):1987. pubmed.ncbi.nlm.nih.gov/29986520
5. Corpas E, Harman SM, Blackman MR. Human growth hormone and human aging. Endocr Rev. 1993;14(1):20-39. pubmed.ncbi.nlm.nih.gov/8491152
6. Khavinson VKh, Bondarev IE, Butyugov AA. Epithalon peptide induces telomerase activity and telomere elongation in human somatic cells. Bull Exp Biol Med. 2003;135(6):590-2. pubmed.ncbi.nlm.nih.gov/12937682
7. Reynolds JC, et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nat Commun. 2021;12(1):470. pubmed.ncbi.nlm.nih.gov/33473109
8. Falutz J, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. N Engl J Med. 2007;357(23):2359-70. pubmed.ncbi.nlm.nih.gov/18057338
9. Rudman D, et al. Effects of human growth hormone in men over 60 years old. N Engl J Med. 1990;323(1):1-6. pubmed.ncbi.nlm.nih.gov/2355952
10. Kim KH, Son JM, Benayoun BA, Lee C. The Mitochondrial-Encoded Peptide MOTS-c Translocates to the Nucleus to Regulate Nuclear Gene Expression in Response to Metabolic Stress. Cell Metab. 2018;28(3):516-524.e7. pubmed.ncbi.nlm.nih.gov/29983246
11. Pickart L, Thaler MM. Tripeptide in human serum which prolongs survival of normal liver cells and stimulates growth in neoplastic liver. Nat New Biol. 1973;243(124):85-7. pubmed.ncbi.nlm.nih.gov/4349963
12. Pickart L. The human tri-peptide GHK and tissue remodeling. J Biomater Sci Polym Ed. 2008;19(8):969-88. pubmed.ncbi.nlm.nih.gov/18644225
13. Anisimov VN, et al. Effect of Epitalon on biomarkers of aging, life span and spontaneous tumor incidence in female Swiss-derived SHR mice. Biogerontology. 2003;4(4):193-202. pubmed.ncbi.nlm.nih.gov/14501183