For instance, tesamorelin, the RCTs look good until you realize that a GLP-1 does the same thing and better (at least based on my research).
Bremelanotide is great if you have hypoactive sexual desire, but I’d probably do trt to treat this instead.
Abaloparatide and Teriparatide are great for women trying to prevent osteoarthritic fractures.
They all have their uses, but, unfortunately, not for me. None of these moves the needle for me. It seems like they all have a fairly narrow use case, unlike Rapamycin or an SGLT2I which has varied and broadly applicable uses.
My feeling is that peptides are great for specific purposes, but aren’t so great as a broad-based longevity treatment that everyone should be injecting. That’s the point I’m trying to make. I also think that influencers are taking these narrow use case peptides and trying to broaden their scope, which isn’t a good thing IMHO.
Role: Longevity Research Analyst To: Biohacking & Clinical Community
Executive Summary
This briefing analyzes five high-profile peptides currently circulating in both clinical and gray-market longevity protocols. While some (Teriparatide, Abaloparatide) have solid Level A evidence for specific pathologies, others (HGH for anti-aging) rely on outdated hypotheses that modern data has largely refuted. Note the critical regulatory divergence between Teriparatide and Abaloparatide regarding osteosarcoma risks.
1. HGH (Human Growth Hormone)
Status: FDA-approved for GH deficiency; widely abused for “anti-aging.”
Claim
Evidence Level
Verdict
Translational Notes
“Reverses biological aging / extends lifespan”
Level A (Refuted)
False
Translational Gap: While GH-deficient mice live shorter lives, GH-resistant (Laron dwarf) mice live longer. In humans, high GH is correlated with increased mortality (cancer/diabetes).
“Increases lean muscle mass in healthy adults”
Level A
Supported
Increases lean body mass (mostly water retention/connective tissue), but does not increase strength or exercise capacity in healthy adults.
“Significantly reduces body fat”
Level A
Supported
Lipolytic effect is confirmed, but risk-benefit ratio is poor compared to GLP-1 agonists.
Key Studies:
Liu et al. (2007):Systematic review: the safety and efficacy of growth hormone in the healthy elderly.Ann Intern Med. (Found small body comp changes but high rates of adverse events like edema and joint pain).
Meinhardt et al. (2010):Systematic review: the effects of growth hormone on athletic performance.Ann Intern Med. (No improvement in strength/Vo2 max).
Safety Profile:
High Risk: Increases insulin resistance (diabetes risk), fluid retention (carpal tunnel, edema), and joint pain.
Cancer Concern: Long-term sustained IGF-1 elevation is associated with increased cancer risk in observational data.
2. Tesamorelin (Egrifta)
Status: FDA-approved for HIV-associated lipodystrophy. GHRH analog.
Consistent reduction (~15-18%) in VAT in HIV populations; distinct from generalized weight loss.
“Improves Cognitive Function (MCI)”
Level B
Promising
A robust RCT showed improved executive function and verbal memory in older adults with Mild Cognitive Impairment (MCI).
“Improves Liver Health (NAFLD)”
Level B
Supported
Reduces liver fat and prevents fibrosis progression in HIV-associated NAFLD.
Key Studies:
Baker et al. (2012):Effects of growth hormone-releasing hormone on cognitive function in adults with mild cognitive impairment and healthy older adults.Arch Neurol. (The primary “biohacker” citation for nootropic use).
Stanley et al. (2014):Reduction in visceral adiposity is associated with improved metabolic profile…Clin Infect Dis.
Safety Profile:
Moderate Risk: Can induce hyperglycemia and increase HbA1c (monitor glucose). Less water retention than HGH due to pulsatile release mechanism.
Contraindications: Active malignancy, pregnancy.
3. Bremelanotide (Vyleesi)
Status: FDA-approved for Hypoactive Sexual Desire Disorder (HSDD) in premenopausal women. Melanocortin agonist.
Claim
Evidence Level
Verdict
Translational Notes
“Increases libido in women (HSDD)”
Level A
Supported
Statistically significant increase in desire and decrease in distress vs. placebo.
“Effective for Erectile Dysfunction / Male Libido”
Level C/E
Uncertain
Off-label use in men is common in gray markets (often as PT-141). Small studies show efficacy, but high rates of side effects.
“Works via CNS, not vascular flow”
Level B
Supported
distinct from PDE5 inhibitors (Viagra); creates “central” arousal rather than just mechanical facilitation.
Key Studies:
Kingsberg et al. (2019):Bremelanotide for the Treatment of Hypoactive Sexual Desire Disorder…Obstet Gynecol.
Safarinejad et al. (2008):Salvage of sildenafil failures with bremelanotide…J Urol. (Male data).
Safety Profile:
Side Effects: High incidence of nausea (40% in some trials), flushing, and headache.
Blood Pressure: Transient increase in systolic BP after injection; contraindicated in uncontrolled hypertension.
4. Abaloparatide (Tymlos) vs. 5. Teriparatide (Forteo)
Status: Both are FDA-approved bone anabolic agents (PTH/PTHrP analogs). Critical Distinction: Regulatory safety warnings have diverged recently.
Claim
Evidence Level
Verdict
Translational Notes
“Increases Bone Mineral Density (BMD) & Reduces Fractures”
Level A
Supported
Both are highly effective. Abaloparatide may have a slight edge in lumbar spine BMD increases.
“Accelerates Fracture Healing (Off-Label)”
Level B
Plausible
Often used off-label for non-unions or acute sports fractures. Data is mixed but generally supportive of faster callus formation.
Miller et al. (2016):Effect of Abaloparatide vs Placebo on New Vertebral Fractures in Postmenopausal Women…JAMA.
Gilsenan et al. (2021):Teriparatide Did Not Increase Adult Osteosarcoma Incidence in a 15-Year US Postmarketing Surveillance Study.J Bone Miner Res. (The study that likely led to the label change).
Safety Check:
Osteosarcoma: Rat studies showed dose-dependent bone cancer with both. Long-term human surveillance cleared Teriparatide, leading the FDA to remove its “Black Box” warning in Nov 2020. Abaloparatide still carries this warning on its label as of late 2025/early 2026.
Hypercalcemia: Abaloparatide has a lower incidence of hypercalcemia compared to Teriparatide.
Final Analyst Note
The “Translational Gap” Warning:
Be extremely wary of protocols mixing HGH with longevity. The data suggests that while it improves cosmetic metrics (skin, muscle size), it likely accelerates cellular aging pathways (mTOR, IGF-1) and contradicts the “low IGF-1” longevity phenotype observed in centenarians.
Winner for Body Comp/Metabolism: Tesamorelin (Lower side effect profile than HGH).
Winner for Bone Health: Teriparatide (proven long-term safety, warning removed) or Abaloparatide (lower hypercalcemia risk).
I"m going to be a little pedantic here but HGH is not a peptide. It’s 191 amino acids long so that clearly puts it into the protein territory. The definition and boundary is a bit blurred but most peptides are <20 amino acids long.
Insulin, at only 51 amino acids, is a classic example that gets classified as both a long peptide and a small protein.
But these are just human classifications…