Comparison Centre

Two compounds, the same questions, no cherry-picking

Marketing compares compounds on whichever measure flatters them. This compares them on the same fields every time — including the awkward ones like how much human safety data exists. Every score here rates the evidence, not the compound: a higher number means stronger or more mature research, not that something is safer or works better.

Compound A

Compound B

Sharing keeps the two compounds you picked.

How to read these scores

Every number here rates the evidence, not the compound. They are editorial 0-100 strength ratings, not percentages, and not a rating out of five stars.

Human efficacy evidence strength — Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
Preclinical evidence strength — Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
Human safety evidence strength — Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number. A score of 80 does not mean “80% safe”.
Evidence level (L0-L5) — the strongest type of study behind the compound, from anecdote (L0) to large replicated human trials (L5). It is a description of the study evidence, not a quality, safety or recommendation rating.
Confidence — how likely we think it is that this rating changes as new research lands. Low confidence means the picture is unsettled, not that the compound is bad.

None of these ratings is medical advice, a safety guarantee, or a recommendation to use anything. How we grade evidence.

Tirzepatide

A dual GIP and GLP-1 receptor agonist with strong Phase 3 weight and glycaemic data.

L5Repeated human trialsApproved medicine (jurisdiction-specific) · FDA (US)

Full profile

Retatrutide

An investigational GIP/GLP-1/glucagon triple agonist with positive pivotal Phase 3 results and no approval anywhere.

L4Good human trialsIn clinical trials

Full profile

How far human research has progressed

Tirzepatide

Approved, large completed Phase 3 programme

Retatrutide

Pivotal Phase 3 results reported (2026); investigational, not approved

Claim-specific benefit evidence

A human exposure study or trial registration does not establish that the claimed benefit occurs.

Tirzepatide

Not separately assessed; see the full profile.

Retatrutide

Not separately assessed; see the full profile.

Human research context

Tirzepatide

Approved, large completed Phase 3 programme

Retatrutide

Pivotal Phase 3 results reported (2026); investigational, not approved

Human efficacy evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Tirzepatide

Strength of the human efficacy evidence92 of 100 evidence strength

Retatrutide

Strength of the human efficacy evidence82 of 100 evidence strength

Preclinical (animal / lab) evidence strength

Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.

Tirzepatide

Strength of the animal and lab evidence85 of 100 evidence strength

Retatrutide

Strength of the animal and lab evidence82 of 100 evidence strength

Human safety evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

Tirzepatide

Strength of the human safety evidence80 of 100 evidence strength

Retatrutide

Strength of the human safety evidence45 of 100 evidence strength

Regulatory status (legal position, not proof it works)

Tirzepatide

Named regulators: FDA (US)

Approved in multiple regions for type 2 diabetes (Mounjaro) and, under a separate brand (Zepbound), for chronic weight management. In December 2024 the FDA approved Zepbound as the first medication for obstructive sleep apnoea in adults with obesity. Additional indications vary by regulator. On 27 August 2026 the US Court of Appeals for the Fifth Circuit upheld FDA's determination that tirzepatide is no longer in shortage, rejecting a challenge brought by compounding interests. The practical effect is to reinforce the shortage delisting and the end of shortage-based routine copying of the approved product; it does not mean every form of individually tailored compounding is categorically unlawful, since narrow statutory exceptions can still apply. This is legal and regulatory evidence about US supply routes, not efficacy or safety evidence about the molecule.

Retatrutide

Check jurisdiction-specific details in the profile.

Not approved in any region. Pivotal Phase 3 results from the TRIUMPH programme were reported in 2026, but positive trial results are not an approval: no regulator has yet licensed it and long-term safety data are still accumulating. Anything sold to the public as 'retatrutide' today is outside approved medical supply. On 24 August 2026 the FDA issued warning letters to US vendors — Royal Peptides LLC, Peptide Partners LLC and TXP Innovations LLC (Tex Peptides) — identifying products marketed as retatrutide as unapproved new drugs, and noting that injectable products sold this way are especially concerning because injection bypasses key body defences. This is regulatory and supply-chain evidence, not evidence that pharmaceutical-grade retatrutide has developed a new toxicity signal. FDA also states explicitly that retatrutide cannot be used in compounding under US federal law, because it is not an FDA-approved drug and is not on a bulk drug substances list permitted for compounding. Again, that is a legal and compounding-status point, not a finding about efficacy or intrinsic toxicity.

Common claims

Tirzepatide

· Greater average weight loss than single-agonist GLP-1s
· Strong glycaemic control
· Improves obstructive sleep apnoea severity in people with obesity

Retatrutide

· The largest weight loss yet seen in an incretin-class trial programme
· Improvements in liver fat
· Better body composition outcomes

How settled our evidence rating is

Tirzepatide

High confidence in ratingL5Repeated human trials

Retatrutide

High confidence in ratingL4Good human trials

Cancer-related questions raised by the biology

These are theoretical or monitored questions raised by how a compound works. They are not evidence that it causes cancer.

Tirzepatide

Carries the same rodent-derived precautionary thyroid labelling as other incretin drugs in several regions. No demonstrated human cancer causation; long-term surveillance is ongoing.

Retatrutide

No demonstrated human cancer signal. Class-level precautionary considerations from incretin pharmacology apply and remain under trial surveillance.

What this adds up to, in plain English

Tirzepatide

Repeated large human trials support specific uses in the groups studied. That is strong evidence something works there — not proof it suits everyone or is free of risk.

Retatrutide

Real controlled human trials exist, but questions about approval, how long benefits last, or long-term safety are still open.

A comparison is not a recommendation

Neither column here is an endorsement, and the compound with the higher numbers is not the “better” or “safer” one — it is simply the one with more or better-quality research behind it. Two compounds can both be poorly evidenced, and better-evidenced says nothing about whether either is a sensible idea for a specific person. That is a conversation for a qualified clinician.