Reviewed by: TRT Locator's Medical Advisory Board.
> This article summarizes and credits content from the Dr. Alex Tatem YouTube channel video on peptide rankings. All tier rankings, clinical assessments, and specific claims featured here are drawn from that video. We strongly recommend watching the original for Dr. Tatem's full commentary.
Not all peptides are created equal, and most online coverage treats them as if they are. Dr. Alex Tatem — a board-certified, fellowship-trained urologist specializing in men's health, performance enhancement, and sexual health — published a comprehensive tier list ranking popular peptides by actual clinical evidence, from the gold standard compounds that genuinely work to the F-tier products he considers dangerous or outright fraudulent. Here is what that ranking looks like and why it matters for men evaluating peptide therapy.
S-Tier: the compounds with the strongest evidence
Growth Hormone (Somatotropin) sits at the top of Dr. Tatem's list as the "gold standard" for the somatotropic pathway. Backed by decades of literature, growth hormone is well established for cutting fat, building lean mass, and supporting recovery through tissue and collagen repair. Tatem's position is direct: GH is superior to every secretagogue and IGF-1 derivative on the market — the alternatives exist largely because of legal restrictions, not because they outperform the real thing (Dr. Alex Tatem, 2024).
That legal context matters. In 1993, an amendment to the Food, Drug, and Cosmetics Act restricted growth hormone prescribing to specific disease states, inadvertently creating the massive market for "secretagogues" designed to stimulate GH release without triggering those restrictions. The secretagogue market, in other words, is a workaround for a regulatory constraint — not a scientific improvement.
Retatrutide is the second S-tier compound. It is a next-generation triple agonist (GLP-1, GIP, and glucagon receptors), and what sets it apart from earlier GLP-1 drugs is its glucagon activity. That mechanism allows users to burn more fat than caloric restriction alone would produce, leading Tatem to call it the "GOAT of cutting agents." It remains in clinical trials, but gray market access already exists — which Tatem flags as a significant sourcing risk given the contamination and heavy metal concerns with Chinese-manufactured compounds (Dr. Alex Tatem, 2024).
A-Tier: strong with legitimate use cases
GHK-Cu (a complex of glycine, histidine, lysine, and copper) earns A-tier. Its most established use is topical — skin hydration, collagen repair, and anti-aging skincare. Where it gets more interesting is injectable use for systemic effects including hair thinning, where anecdotal reports are described by Tatem as "universally positive." The honest caveat: high-quality clinical trial evidence for injectable GHK-Cu is sparse, and the positive data is largely anecdotal rather than randomized-controlled-trial-grade (Dr. Alex Tatem, 2024).
B-Tier: effective in specific contexts
Tesamorelin is a growth hormone-releasing hormone (GHRH) analog that is FDA-approved for treating lipodystrophy — the accumulation of visceral belly fat — in HIV patients. Tatem rates it effective for reducing central fat in a way that is clinically meaningful. The practical problem is cost: pharma-grade tesamorelin is expensive, making it less accessible than alternatives that achieve similar metabolic results at lower price points.
IGF-1 LR3 is a long-release version of insulin-like growth factor 1, and Tatem identifies it as the only "new wave" peptide that can actually stimulate hypertrophy — direct muscle growth — rather than just facilitating recovery or fat loss. It ranks below growth hormone because GH remains more available and cost-effective for most users. There is a meaningful side effect to flag: IGF-1 LR3 can cause acute drops in blood sugar, producing sweating and insulin-shock-like reactions, particularly around the injection time (Dr. Alex Tatem, 2024).
C-Tier: limited human evidence, split results
BPC-157 is derived from gastric juice and is designed to speed healing by organizing fibroblasts at injury sites. Despite bold anecdotal reports — including claims of curing spinal stenosis — Tatem places it in C-tier because the evidence is overwhelmingly drawn from animal and benchtop models, not human clinical trials. The FDA moved it to Category 2 (ineligible for compounding) in 2023 citing this exact gap.
TB-500 (a derivative of Thymosin Beta-4) aids cell movement during wound repair. Tatem describes user reports as split roughly 50/50 — half of users find it transformative, the other half see no effect whatsoever. That pattern is consistent with limited and variable human data.
The "Glow Stack" — a combination of BPC-157, TB-500, and GHK-Cu — is popular on social media and longevity forums. Tatem gives it C-tier using a straightforward principle: a stack is only as strong as its weakest component. Combining two C-tier compounds with one A-tier compound does not elevate the stack above C.
D-Tier: less effective than its alternatives
Ipamorelin is a growth hormone secretagogue that targets the ghrelin receptor to stimulate GH release. Clinical trials for its original intended use (gut healing) returned equivocal results, and when assessed on its primary off-label uses, the math works against it: it is less effective for weight loss than GLP-1 drugs, and less effective for boosting IGF-1 and GH than actual growth hormone. It is not dangerous, but Tatem's view is that there are better tools for every application Ipamorelin is typically used for (Dr. Alex Tatem, 2024).
