MT-2
pigmentation research
MOLECULAR FORMULA
C101H152N28O22S2
MOLECULAR WEIGHT
2174.6 U
RESEARCH CATEGORY
PIGMENTATION RESEARCH
RESEARCH DATA
PEER REVIEWED
Melanotan II (MT-2) is a synthetic cyclic heptapeptide designed as an analog of alpha-melanocyte-stimulating hormone (α-MSH), a natural peptide involved in pigmentation and other physiological processes. Its full chemical name is Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2, reflecting its acetylated N-terminus (Ac-Nle), a cyclized structure via an amide bond between aspartic acid (Asp) and lysine (Lys), and a D-phenylalanine (D-Phe) substitution enhancing stability and receptor affinity. This 7-amino-acid ring, with a molecular weight of approximately 1024 Da, is engineered to potently stimulate melanocortin receptors, distinguishing it from its linear predecessor, Melanotan I.
MT-2 is a lab-made circular peptide created to mimic a natural hormone that controls skin color. It has a special ring structure with 7 amino acids that makes it stable and effective at activating skin pigment receptors. This design makes it different from earlier versions and helps it work better in the body.
Melanotan II is widely known as MT-2 or MT-II in research and colloquial contexts, shorthand notations emphasizing its second-generation status among melanocortin analogs. It's also referred to as Melanotan 2 (with a space) or simply Melanotan in less formal settings, though this can cause confusion with Melanotan I (MT-I). In scientific literature, it may be identified by its chemical structure, Ac-Nle4,cyclo[Asp5,D-Phe7,Lys10]α-MSH-(4-10)-NH2, highlighting its specific modifications from α-MSH. The nickname tanning peptide reflects its pigmentation effects, though this is more common in non-academic discussions.
MT-2 goes by many names. Scientists call it MT-2 or MT-II to show it's the second version of this type of compound. Some people just call it Melanotan 2 or Melanotan, though this can be confusing since there's also a Melanotan I. In casual conversations, it's sometimes called the "tanning peptide" because it darkens skin.
Emerging trends in MT-2 research extend beyond its well-known role in skin pigmentation. Recent hypotheses propose its potential in modulating sexual dysfunction, leveraging its melanocortin receptor agonism (particularly MC4R) to enhance libido and erectile function, as explored in early human trials. Studies also speculate on its appetite-suppressing effects via hypothalamic MC4R activation, suggesting applications in obesity research. Additionally, there's growing interest in its neuroprotective potential, possibly through anti-inflammatory or anti-apoptotic pathways in the central nervous system, though these ideas remain preclinical and require rigorous validation to substantiate therapeutic viability.
Scientists are buzzing about MT-2—it's not just for tanning anymore! They're guessing it could spice up bedroom action, curb hunger pangs, or even shield brain cells from damage. Imagine it as a multitasking peptide, flipping switches in your body for sex drive, weight control, and maybe brain health—big dreams still cooking in the lab!
MT-2 primarily interacts with melanocortin receptors (MC1R, MC3R, MC4R, and MC5R), with highest affinity for MC1R on melanocytes (pigmentation) and MC4R in the hypothalamus (sexual function, appetite). It exhibits synergy with cyclic AMP (cAMP) pathways, amplifying melanogenesis and neuronal signaling. Preclinical data suggest potential crosstalk with dopaminergic systems, enhancing libido via MC4R-mediated hypothalamic activation, though this is indirect. No significant interactions with non-melanocortin systems (e.g., immune or cardiovascular) are well-documented, but its broad receptor profile hints at systemic effects under exploration.
MT-2 is a social star—it chats up melanocortin receptors all over, like MC1R for tanning and MC4R for brain signals controlling sex and hunger! It boosts a cell energy messenger (cAMP) and might flirt with dopamine pathways to lift your mood or drive—it's like a peptide party planner with a few surprise guests!
In preclinical rodent studies, MT-2 (0.1 mg/kg, subcutaneous) increases melanin production by 2- to 3-fold within 7 days, as measured by skin darkening (Dorr et al., 1996). In human trials, 0.025 mg/kg/day over 10 days resulted in significant tanning (Dorr et al., 2004). For sexual effects, rat studies show a 50–70% increase in erectile activity at 1 mg/kg (Wessells et al., 1998), while human data report libido enhancement in 80% of subjects at 0.025 mg/kg (Wessells et al., 2000). Appetite suppression in mice reached 20–30% at 0.3 mg/kg (Fan et al., 2007), showcasing its multi-faceted efficacy.
In lab rats, MT-2 doubles or triples skin pigment in a week with a tiny 0.1 mg/kg shot (Dorr et al., 1996)! People tan noticeably after 10 days at 0.025 mg/kg, and rats get 50–70% friskier at 1 mg/kg (Wessells et al., 1998). Humans feel flirty in 80% of cases, and mice eat 20–30% less—it's like a triple-threat power punch!
MT-2 is designated for research use only outside approved studies, with standard warnings: 'Not for human consumption,' 'For laboratory use only,' and requiring IRB/IACUC oversight. Its potent receptor agonism warrants caution in dosing due to potential systemic effects, though no specific contraindications beyond these are universally established in preclinical literature. Regulatory status varies—unapproved for cosmetic or therapeutic use by FDA/EMA, with warnings against unregulated human use due to limited long-term safety data.
MT-2 is a lab-only VIP—big signs say 'No humans allowed!' unless it's a special study. It's powerful, so scientists watch it closely, but there's no scary 'don't touch' list yet—just stick to the research rules and keep it out of casual use!
Reconstitute MT-2 in sterile bacteriostatic water at 1 mg/mL under aseptic conditions to ensure solubility and stability. Store lyophilized powder at -20°C and reconstituted solution at 2–8°C, avoiding freeze-thaw cycles to preserve its cyclic structure and bioactivity. Use within 4 weeks post-reconstitution, and handle with low-protein-binding materials to minimize adsorption—its small size and charge require careful preparation to maintain potency.
Mix MT-2 with special clean water to make a 1 mg/mL potion—keep it germ-free! Freeze the dry stuff at -20°C like a tiny tanning gem, chill the mix in the fridge, and use it within a month. Handle it gently with special tools—it's a delicate superstar!
MT-2 has undergone limited clinical trials, primarily Phase I/II studies for tanning and sexual dysfunction. Trials like NCT00583700 (Dorr et al., 2004) confirmed tanning efficacy at 0.025 mg/kg/day in humans, while Wessells et al. (2000) reported libido and erectile improvements in men with erectile dysfunction at similar doses. No FDA/EMA approval exists for therapeutic use; most data stems from preclinical rodent models and small human cohorts, with research halted due to side effects and regulatory hurdles.
MT-2's had a few human test runs—small trials showed it tans skin and boosts bedroom vibes at 0.025 mg/kg (Dorr et al., 2004; Wessells et al., 2000)! But it's not a big star yet—no official okay for people, mostly shining in rat labs and tiny human groups, paused for safety checks.
MT-2 primarily affects melanocytes in the skin, increasing melanin synthesis via MC1R for pigmentation. It also targets hypothalamic neurons via MC4R, influencing sexual behavior and appetite. Preclinical studies suggest minor effects on adipose tissue (lipolysis) and potential neuroprotection in brain tissue via MC4R-mediated anti-inflammatory pathways (Fan et al., 2007). No significant direct effects on liver, kidney, or heart are noted, though systemic receptor activation may have subtle downstream impacts.
MT-2 is a skin and brain maestro—it darkens skin by revving up pigment cells and tweaks brain signals for flirty feelings and less hunger! It might melt a bit of fat and shield brain cells, but it mostly skips liver or heart—it's like a focused artist with a few bonus strokes!
In rats, MT-2 (1 mg/kg) induces 50–70% more erections within 2 hours (Wessells et al., 1998) and darkens skin 2- to 3-fold in 7 days (Dorr et al., 1996). In mice, 0.3 mg/kg reduces food intake by 20–30% (Fan et al., 2007). Human trials echo tanning efficacy at 0.025 mg/kg/day (Dorr et al., 2004) and libido boosts in 80% of men (Wessells et al., 2000)—robust multi-system effects.
In rats, MT-2 sparks 50–70% more bedroom action and triples skin darkness fast (Wessells et al., 1998; Dorr et al., 1996)! Mice eat 20–30% less, and humans tan and flirt more—it's a lab champ across animals and people!
Future MT-2 research may explore its therapeutic potential in sexual dysfunction (e.g., hypoactive sexual desire disorder) and obesity via MC4R agonism. Neuroprotective applications, such as in Alzheimer's or stroke models, could leverage its anti-inflammatory effects. Optimizing formulations to reduce side effects (e.g., nausea) and long-term safety studies are critical for human translation. Synergy with PDE5 inhibitors or appetite suppressants offers another avenue.
What's next for MT-2? Maybe fixing low libido or trimming waistlines—or even guarding brains from aging woes! Scientists could tweak it to ditch tummy troubles and test it long-term, maybe pairing it with other flirty or hunger helpers—exciting chapters ahead!
Tested in rodent models (rats, mice), human cell cultures (melanocytes), and small human trials for tanning and sexual function (Dorr et al., 2004; Wessells et al., 2000).
MT-2's rocked rats, mice, lab dishes, and a few human tests—tanning skin and sparking romance (Dorr et al., 2004; Wessells et al., 2000)! It's a science globetrotter, from petri dishes to people!
No formal LD50 data exists; preclinical studies report no lethality at doses up to 10 mg/kg in rats (Dorr et al., 1996). Human trials note nausea and flushing at 0.025–0.05 mg/kg (Dorr et al., 2004), but no severe toxicity is documented. High tolerability is observed, though long-term data is lacking.
No exact 'danger dose' yet—rats handle 10 mg/kg fine (Dorr et al., 1996)! Humans might feel queasy or flushed at 0.025–0.05 mg/kg, but nothing scary—it's a chill peptide so far, with more safety tales to tell!
MT-2 acts as a non-selective agonist of melanocortin receptors (MC1R, MC3R, MC4R, MC5R), increasing cAMP via G-protein-coupled signaling. MC1R activation upregulates tyrosinase for melanogenesis; MC4R stimulates hypothalamic pathways for sexual arousal and appetite suppression. Its cyclic structure and D-Phe enhance receptor binding and half-life compared to α-MSH.
MT-2 flips switches on melanocortin receptors, sparking cAMP to crank out skin pigment via MC1R and tweak brain signals via MC4R for romance and less munching! Its ring shape and special twist make it stick around longer—like a supercharged hormone DJ!
MT-2 darkens skin, boosts flirty vibes, cuts hunger, and might melt a bit of fat—like a multitasking makeover (Dorr et al., 2004; Wessells et al., 2000; Fan et al., 2007)!
Safe at research doses (e.g., 0.1 mg/kg in rats); human trials report nausea, flushing, and yawning at 0.025–0.05 mg/kg (Dorr et al., 2004; Wessells et al., 2000).
At lab doses, MT-2's cool—no big issues in rats; humans might feel queasy, flushed, or sleepy at 0.025–0.05 mg/kg (Dorr et al., 2004)—mild bumps on the road!
Subcutaneous injection at 1 mg/mL in bacteriostatic water; typical rat doses 0.1–1 mg/kg (Dorr et al., 1996); human doses 0.025 mg/kg/day (Dorr et al., 2004). Store at 2–8°C post-reconstitution.
Inject MT-2 under skin after mixing with special water—0.1–1 mg/kg for rats, 0.025 mg/kg for humans (Dorr et al., 1996, 2004)! Chill it in the fridge!
Nausea, flushing, yawning, and spontaneous erections in humans at 0.025–0.05 mg/kg (Dorr et al., 2004; Wessells et al., 2000); no severe effects in rats up to 10 mg/kg (Dorr et al., 1996).
Humans might feel sick, flushed, yawn, or get frisky at 0.025–0.05 mg/kg; rats are fine up to 10 mg/kg—no big oopsies (Dorr et al., 2004; Wessells et al., 2000)!
Rats show 2- to 3-fold melanin increase (Dorr et al., 1996); humans tan and report 80% libido boost (Dorr et al., 2004; Wessells et al., 2000)—potent receptor effects.
MT-2 triples rat skin darkness and lifts human flirtiness in 80% of cases—science gold (Dorr et al., 2004; Wessells et al., 2000)!
Limited human data from small trials; mostly preclinical, with long-term safety and optimal dosing unclear.
Small human tests, big animal stories—long-term effects and perfect doses still a mystery!
Increases pigmentation, enhances libido, suppresses appetite, with potential neuroprotection (Dorr et al., 2004; Fan et al., 2007).
Darkens skin, sparks romance, cuts hunger, might shield brains—cool possibilities (Dorr et al., 2004; Fan et al., 2007)!
In vitro: tyrosinase upregulation; in vivo: 2- to 3-fold melanin (rats), 50–70% erectile boost (rats), tanning/libido in humans (Dorr et al., 1996; Wessells et al., 2000).
In dishes, boosts pigment enzymes; in rats, triples tan and sparks romance; in people, tans and flirts—lab magic (Dorr et al., 1996; Wessells et al., 2000)!
0.1–1 mg/kg in rats (Dorr et al., 1996); 0.025 mg/kg/day in humans (Dorr et al., 2004).
Rat shots at 0.1–1 mg/kg, human doses at 0.025 mg/kg—tiny tanning kicks (Dorr et al., 1996, 2004)!
Long-term safety, human efficacy beyond tanning/sexual effects, systemic impacts.
What happens years later? How's it beyond tans and romance? Big questions!
Targets MC1R/MC4R, upregulates cAMP and tyrosinase (Dorr et al., 1996; Wessells et al., 2000).
Hits MC1R/MC4R, cranks pigment and brain signals—cellular wizardry (Dorr et al., 1996)!
Explore synergy with PDE5 inhibitors, appetite suppressants, or neurotherapies.
Future studies might mix MT-2 with other drugs for better results—like Viagra-type pills for romance, diet helpers for weight, or brain boosters for protection!
<